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SynC · SynC Standards

Engine Generators

Rev10
IssuedOct 17, 2026
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1 Scope

NOTE This standard governs the packaged engine-generator set: a reciprocating internal combustion engine, a directly coupled synchronous alternator, the governor and voltage regulator, the set-mounted controller, the starting and charging system, the cooling, fuel, and exhaust systems on the skid, and the enclosure or base, furnished as one integrated assembly listed to UL 2200. (1.1)
NOTE Several product decisions are made independently of one another and are stated as independent selections in this standard: the engine fuel, the installation configuration and enclosure, the cooling arrangement, the excitation system, the fuel storage arrangement at the set, and the starting battery type. Every combination is manufactured, and this standard does not assume that one selection implies another. (1.2)
NOTE The set is one component of a system whose classification, capacity, and transfer scheme are decided elsewhere, so the values that follow from that system, including the rating category, the runtime, the cold-start provisions, the emissions rule, and the neutral bonding at the set, are stated on the datasheet as derived values that point at their cause rather than as decisions made at the set. (1.3)
NOTE The following are governed elsewhere and are outside this standard: (1.4)
  • the classification of loads, the NFPA 110 level, type, and class of the system, the capacity the alternate source must carry at each load step, the number of sets, and the transfer scheme (Emergency And Standby PowerEmergency and Standby Power SystemsResolves to the current adopted revision.sync/emergency-and-standby-power)
  • the automatic transfer switch, its engine-start contacts, its time delays and exerciser, and the neutral treatment that decides whether the set is a separately derived system (Automatic Transfer SwitchesAutomatic Transfer SwitchesResolves to the current adopted revision.sync/automatic-transfer-switches)
  • the bulk fuel storage tank as a vessel, including a remote aboveground or underground tank and its containment, venting, overfill prevention, and leak detection (Fuel Dispensing And Storage TanksFuel Storage TanksResolves to the current adopted revision.sync/fuel-dispensing-and-storage-tanks)
  • the fuel-oil transfer pumps, the day-tank fill and overflow controls, fuel polishing, and the supply and return piping between the bulk tank and the skid connection (Fuel Oil SystemsFacility Fuel-Oil SystemsResolves to the current adopted revision.sync/fuel-oil-systems)
  • the natural gas and propane piping from the meter, regulator, or tank to the connection at the engine gas train (Fuel Gas PipingFacility Liquefied-Petroleum and Fuel Gas PipingResolves to the current adopted revision.sync/fuel-gas-piping)
  • the feeders from the set to the transfer switch and the raceways that carry them and the control wiring (Conductors And CablesConductors and CablesResolves to the current adopted revision.sync/conductors-and-cables, Raceways And ConduitRaceways and ConduitResolves to the current adopted revision.sync/raceways-and-conduit)
  • the grounding electrode system and the bonding of a separately derived system (Grounding And BondingGrounding and Bonding for Electrical SystemsResolves to the current adopted revision.sync/grounding-and-bonding)
  • the short-circuit, coordination, and arc-flash studies that establish the breaker settings and the labels (Short Circuit StudyShort-Circuit StudyResolves to the current adopted revision.sync/short-circuit-study, Protective Coordination StudyProtective Device Coordination StudyResolves to the current adopted revision.sync/protective-coordination-study, Arc Flash StudyArc-Flash Hazard AnalysisResolves to the current adopted revision.sync/arc-flash-study)
  • the concrete pad as a structure (Concrete PadsConcrete Equipment PadsResolves to the current adopted revision.sync/concrete-pads) and the room an indoor set occupies (Electrical RoomsElectrical RoomsResolves to the current adopted revision.sync/electrical-rooms)
  • paralleling switchgear and utility-interactive operation (Generator Paralleling SwitchgearGenerator Paralleling SwitchgearResolves to the current adopted revision.sync/generator-paralleling-switchgear), medium-voltage alternators, portable sets, turbines, fuel cells, and stored-energy sources
1.5 The location of the set shall be as indicated on the electrical plans.
1.6 The Contractor shall coordinate the rating category, the runtime, the neutral bonding, the engine-start interface, the fuel supply, and the annunciation of the set with the standards named in this section before the set is released for manufacture.

2 Referenced Standards

2.1 Equipment, materials, and installation shall comply with the latest adopted edition of each of the following unless a specific edition is cited.
2.2 Where the contract documents, the air permit, the Authority Having Jurisdiction, or two referenced standards impose conflicting requirements, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.
Standard Title
UL 2200 Stationary Engine Generator Assemblies
UL 1236 Battery Chargers for Charging Engine-Starter Batteries
UL 142 Steel Aboveground Tanks for Flammable and Combustible Liquids
UL 2085 Protected Aboveground Tanks for Flammable and Combustible Liquids
NFPA 70 National Electrical Code (Articles 110, 250, 445, 700, 701, 702, 705, and 708)
NFPA 70E Standard for Electrical Safety in the Workplace
NFPA 110 Standard for Emergency and Standby Power Systems
NFPA 99 Health Care Facilities Code
NFPA 37 Standard for the Installation and Use of Stationary Combustion Engines and Gas Turbines
NFPA 30 Flammable and Combustible Liquids Code
NFPA 54 National Fuel Gas Code
NFPA 58 Liquefied Petroleum Gas Code
ISO 8528-1 Reciprocating Internal Combustion Engine Driven Alternating Current Generating Sets, Part 1: Application, Ratings and Performance
ISO 8528-3 Reciprocating Internal Combustion Engine Driven Alternating Current Generating Sets, Part 3: Alternating Current Generators for Generating Sets
ISO 8528-5 Reciprocating Internal Combustion Engine Driven Alternating Current Generating Sets, Part 5: Generating Sets
ISO 8528-6 Reciprocating Internal Combustion Engine Driven Alternating Current Generating Sets, Part 6: Test Methods
ISO 8528-10 Reciprocating Internal Combustion Engine Driven Alternating Current Generating Sets, Part 10: Measurement of Airborne Noise
ISO 3046-1 Reciprocating Internal Combustion Engines, Performance, Part 1: Declarations of Power, Fuel and Lubricating Oil Consumptions, and Test Methods
NEMA MG 1 Motors and Generators
IEEE 446 Recommended Practice for Emergency and Standby Power Systems for Industrial and Commercial Applications
IEEE 1547 Standard for Interconnection and Interoperability of Distributed Energy Resources with Associated Electric Power Systems Interfaces
EGSA 100B Performance Standard for Engine Cranking Batteries Used with Engine Generator Sets
ASTM D975 Standard Specification for Diesel Fuel
40 CFR Part 60 Subpart IIII Standards of Performance for Stationary Compression Ignition Internal Combustion Engines
40 CFR Part 60 Subpart JJJJ Standards of Performance for Stationary Spark Ignition Internal Combustion Engines
40 CFR Part 63 Subpart ZZZZ National Emission Standards for Hazardous Air Pollutants for Stationary Reciprocating Internal Combustion Engines
40 CFR Part 1039 Control of Emissions from New and In-Use Nonroad Compression-Ignition Engines
ASCE 7 Minimum Design Loads and Associated Criteria for Buildings and Other Structures (Chapter 13)
ICC-ES AC156 Acceptance Criteria for Seismic Certification by Shake-Table Testing of Nonstructural Components
ANSI/NETA ATS Standard for Acceptance Testing Specifications for Electrical Power Equipment and Systems

3 Submittals

3.1 Action Submittals

3.1.1 The Contractor shall submit the following for review before the set is released for manufacture:
  • product data for the engine, the alternator, the governor and voltage regulator, the controller, the main line circuit breaker, the battery charger, the cold-start provisions, the enclosure, the sub-base tank, the silencer, the aftertreatment, and every accessory, identifying the UL 2200 listing of the complete assembly
  • the rating statement giving the standard-condition output, the site-rated output at the ambient temperature and altitude of the installation, the rating category under ISO 8528-1, and the ISO 8528-5 performance class
  • shop drawings giving plan and elevations, weight with and without fuel, the lifting points, the conduit and cable entry areas, the fuel, exhaust, and coolant connections, the cooling air intake and discharge openings, and the service clearances the manufacturer requires
  • a one-line diagram of the set showing the alternator, the neutral bonding at the set, the main line circuit breaker, the instrument transformers, and the control interfaces with the transfer switch and the remote annunciator
  • alternator data giving the reactances, the decrement curve, the sustained short-circuit current, and the temperature rise at the site-rated output
  • the step-load analysis giving the transient voltage and frequency deviation and the recovery time for the load steps established under Emergency And Standby PowerEmergency and Standby Power SystemsResolves to the current adopted revision.sync/emergency-and-standby-power, with the largest single step identified
  • the emissions certificate of the engine under the rule and tier derived under this standard, and the aftertreatment data where aftertreatment is furnished
  • sound data giving the octave-band and A-weighted sound pressure level at 7 m at full load for the configuration furnished
  • the fuel consumption table at 25, 50, 75, and 100 percent of the site-rated output, and the calculated runtime for the tank capacity furnished
  • cooling data giving the heat rejection, the air flow, the static pressure available at the radiator discharge, and the coolant and after-cooler temperatures at the site design ambient
  • the seismic certification for the set, where the datasheet requires one
  • the proposed initial value of every programmable setting and alarm set point, on a settings record the Engineer of Record will review
Action Submittalscheckbox
☑ Product data with the UL 2200 listing of the complete assembly
☑ Rating statement with the site-rated output, rating category, and performance class
☑ Shop drawings with dimensions, weights, connections, and clearances
☑ One-line diagram of the set
☑ Alternator reactance, decrement, and short-circuit data
☑ Step-load voltage and frequency analysis
☑ Emissions certificate and aftertreatment data
☑ Sound data at 7 m
☑ Fuel consumption table and runtime calculation
☑ Cooling performance data at the site design ambient
☐ Seismic certification
☑ Proposed settings record
3.1.2 The set shall not be released for manufacture until the action submittals covering it have been reviewed and returned.
NOTE The rating statement is the submittal that most often comes back wrong, because the output printed on a catalog page is the standard-condition rating at the manufacturer's reference ambient and altitude, and the output the set delivers on the project is the site-rated output after the corrections for the actual ambient, the actual altitude, and the fuel furnished. (3.1.3)

3.2 Informational Submittals

3.2.1 The Contractor shall submit the following with or before the action submittals:
  • the manufacturer's qualification statement required under Quality Assurance
  • the factory test procedure, where the datasheet selects witnessed factory testing
  • the field testing firm's qualification statement and the proposed field test procedure
  • the seismic anchorage calculation and anchor detail for the installed condition
  • the air permit application or the registration the air quality authority requires for the engine, and the permit or registration when issued
  • the manufacturer's statement of the required fuel supply pressure and full-load fuel flow at the engine connection, where the set is fueled by natural gas or propane
Informational Submittalscheckbox
☑ Manufacturer's qualification statement
☐ Factory test procedure
☑ Field testing firm qualification and test procedure
☑ Seismic anchorage calculation and detail
☑ Air permit application and permit
☐ Required gas supply pressure and flow statement

3.3 Closeout Submittals

3.3.1 The Contractor shall submit the following before the set is accepted:
  • the certified factory production test report for the set, identified by serial number
  • the manufacturer's field startup report, where the datasheet requires manufacturer startup
  • the field acceptance test report, giving every measured value, the acceptance criterion applied, and the tester's determination
  • the installation acceptance test record required by NFPA 110 Chapter 7, where the set serves a system classified under NFPA 110
  • the settings record as commissioned, giving the final value of every programmable setting and alarm set point
  • as-built drawings reflecting the installed fuel, exhaust, coolant, and cable routing and every field change
  • operation and maintenance data giving the controller programming procedure, the alarm and shutdown response procedure, the maintenance intervals and consumables, the fuel quality program, the run-hour limits of the air permit, and the torque values for every accessible connection
  • the warranty documentation for the set and for the installation, with the warranty commencement date
  • a signed receipt from the Owner for the spare parts delivered
Closeout Submittalscheckbox
☑ Certified factory production test report
☐ Manufacturer field startup report
☑ Field acceptance test report
☐ NFPA 110 installation acceptance test record
☑ Settings record as commissioned
☑ As-built drawings
☑ Operation and maintenance data
☑ Warranty documentation with commencement date
☐ Spare parts receipt
NOTE The run-hour limits of the air permit belong in the operation and maintenance data because they bind the Owner for the life of the engine, and an Owner who exercises the set under load every week without knowing the limit can exceed it within the first year. (3.3.2)

4 Quality Assurance

4.1 Manufacturer Qualifications

4.1.1 The set shall be produced by a manufacturer that has manufactured UL 2200 listed engine-generator sets of the same fuel type and output range for not less than the period indicated in the datasheet.
Manufacturer Production Experiencerange
years
351020
4.1.2 The manufacturer shall maintain a factory-authorized service organization able to reach the site, and shall state in the qualification statement the location of the nearest service center, the parts stocked there, and the number of technicians trained on the controller furnished.

4.2 Single-Source Responsibility

4.2.1 The engine, the alternator, the governor and voltage regulator, the controller, the base or sub-base tank, the enclosure, and every set-mounted accessory shall be furnished by the generator manufacturer as one integrated assembly, and the generator manufacturer shall be responsible for the matching of the engine to the alternator and for the performance of the assembly.
4.2.2 A set assembled by the installing Contractor from separately procured components shall not be furnished.

4.3 UL 2200 Listing

4.3.1 The complete set as furnished, including the enclosure and the sub-base tank where furnished, shall be listed and labeled to UL 2200 by a Nationally Recognized Testing Laboratory.
4.3.2 The sub-base tank shall be listed to UL 142 or UL 2085 as selected under Fuel Dispensing And Storage TanksFuel Storage TanksResolves to the current adopted revision.sync/fuel-dispensing-and-storage-tanks, and the battery charger shall be listed to UL 1236.
NOTE UL 2200 is a listing of the assembly and not of its parts, so a listed engine on a listed alternator inside a listed enclosure is not a listed set unless the assembly itself carries the mark. (4.3.3)

4.4 Field Testing Firm Qualifications

4.4.1 Field acceptance testing shall be performed by a testing firm qualified in accordance with Electrical Acceptance TestingElectrical Acceptance TestingResolves to the current adopted revision.sync/electrical-acceptance-testing, or by the manufacturer's factory-trained technicians where the datasheet requires manufacturer startup.
4.4.2 The technician who performs the load test and the NFPA 110 installation acceptance test shall have documented experience commissioning sets of the same fuel type and controller family.

5 Environmental and Service Conditions

5.1 Rating Basis

NOTE ISO 8528-1 states the output of a set at standard reference conditions of 25°C air temperature, 100 kPa barometric pressure, and 30 percent relative humidity, and every site departs from that basis in at least one respect; the engine loses power as the air thins and warms, and the alternator loses margin as its cooling air warms, so the output the set delivers on the project is the standard-condition output after both corrections. (5.1.1)
5.1.2 The set shall deliver the rated output selected under this standard at the ambient temperature and altitude of the installation, and the manufacturer shall state the corrections applied in the rating statement.

5.2 Ambient Temperature

5.2.1 A set installed outdoors, or in a space that follows the outdoor temperature, shall be rated for Site Ambient Temperature MaximumSite Ambient Temperature MaximumParameterEach project supplies its own value.site-ambient-temperature-maximum, and the cooling system shall hold the coolant and after-cooler temperatures within the engine manufacturer's limits at that temperature with the set carrying its rated output.
5.2.2 The design ambient temperature of the room for a set installed indoors in a ventilated room shall be as indicated in the datasheet.
Indoor Room Design Ambient Temperaturerange
°C
25303540455055
Default: Not less than 40 °C
NOTE A 40°C room ambient is the condition most manufacturers rate a set-mounted radiator for without a larger core, so it is the value at which the catalog cooling data applies; a generator room whose ventilation cannot hold that temperature at full load with the radiator discharging into the room, or a room in a hot climate, carries a higher value at the cost of a larger radiator or a reduced rating. (5.2.3)
5.2.4 The room ventilation and combustion air openings shall be sized for the radiator air flow, the combustion air, and the heat radiated from the engine and exhaust at the room design ambient, and shall be as indicated on the mechanical drawings.

5.3 Altitude

5.3.1 The engine and the alternator shall be de-rated for AltitudeAltitudeParameterEach project supplies its own value.altitude in accordance with the manufacturer's published correction factors, and the site-rated output shall reflect the correction.
NOTE A naturally aspirated engine loses power steadily with altitude because the mass of air in each cylinder falls with the barometric pressure, and a turbocharged engine holds its output to a higher altitude and then de-rates more steeply; the alternator de-rates separately for the thinner cooling air, so the two corrections are applied to the two components and the site rating is the lower of the results. (5.3.2)
5.3.3 Ambient temperature de-rating and altitude de-rating shall be applied cumulatively where both conditions apply.

5.4 Cold Weather

5.4.1 The cold-start provisions furnished on the set shall be as indicated in the datasheet.
Cold-Start Provisionscheckbox
☐ Jacket water heater
☐ Battery warmer
☐ Lube oil heater
☐ Intake air heater or glow plugs
☐ Diesel fuel heater
☐ Enclosure heater
Derived — the NFPA 110 level and type assigned under the emergency and standby power standard, and Site Ambient Temperature MinimumSite Ambient Temperature MinimumParameterEach project supplies its own value.site-ambient-temperature-minimum for a set installed outdoors or in a space that follows the outdoor temperature (by default)
5.4.2 A thermostatically controlled jacket water heater shall be furnished on every set serving a system classified as Level 1 under NFPA 110, in accordance with NFPA 110 Chapter 5, and on every set installed outdoors or in a space that follows the outdoor temperature where Site Ambient Temperature MinimumSite Ambient Temperature MinimumParameterEach project supplies its own value.site-ambient-temperature-minimum is below 4°C.
5.4.3 The jacket water heater shall hold the coolant at the temperature the engine manufacturer requires for a start and load acceptance within the type time assigned under Emergency And Standby PowerEmergency and Standby Power SystemsResolves to the current adopted revision.sync/emergency-and-standby-power, and shall be sized for the heat loss of the engine at the lowest temperature of the space.
5.4.4 A battery warmer shall be furnished on every set installed outdoors or in a space that follows the outdoor temperature where Site Ambient Temperature MinimumSite Ambient Temperature MinimumParameterEach project supplies its own value.site-ambient-temperature-minimum is at or below 0°C.
5.4.5 A lube oil heater shall be furnished on every set installed outdoors or in a space that follows the outdoor temperature where Site Ambient Temperature MinimumSite Ambient Temperature MinimumParameterEach project supplies its own value.site-ambient-temperature-minimum is at or below −18°C, and wherever the engine manufacturer requires one for the start time assigned.
5.4.6 A diesel fuel heater shall be furnished on every diesel set installed outdoors or in a space that follows the outdoor temperature where Site Ambient Temperature MinimumSite Ambient Temperature MinimumParameterEach project supplies its own value.site-ambient-temperature-minimum is below the cloud point of the fuel the Owner will stock.
NOTE Cold coolant lengthens the crank, cold lube oil raises the cranking torque, and a cold lead-acid battery loses the capacity to deliver it, so the three heaters act on the three things that decide whether a cold engine reaches rated speed within ten seconds; a diesel fuel heater addresses the separate failure in which wax crystals block the filter before the engine has warmed the fuel. (5.4.7)
5.4.8 Every heater shall be powered from a dedicated branch circuit on the normal source, so that the heater is energized whenever the engine is not running, and the heater circuits shall be as indicated on the panel schedules.

5.5 Seismic Qualification

5.5.1 The seismic certification required for the set shall be as indicated in the datasheet.
Seismic Certification Requirementselect
No seismic certification required
Anchorage design only, in accordance with ASCE 7 Chapter 13
Special certification of the set as an active component in accordance with ASCE 7 Section 13.2.2
Special certification with a state health care pre-approval listing
Derived — Seismic Design CategorySeismic Design CategoryParameterEach project supplies its own value.seismic-design-category and the component importance factor assigned to the set under ASCE 7 Chapter 13 (by default)
NOTE Anchorage keeps the set on its pad; special certification demonstrates that the set still starts and carries load after the design earthquake, which ASCE 7 requires of a component whose importance factor is above 1.0. A set serving egress lighting, fire pumps, smoke control, or another life-safety load carries an importance factor of 1.5 under ASCE 7, and so does a set needed for the continued operation of a Risk Category IV facility. (5.5.2)
5.5.3 Where special certification is required, the certification shall be by shake-table test in accordance with ICC-ES AC156 or by analysis accepted by the Authority Having Jurisdiction under the seismic provisions of Adopted Building CodeAdopted Building CodeParameterEach project supplies its own value.adopted-building-code, and the certificate shall cover the set as furnished, including the engine, the alternator, the controller, the sub-base tank, the enclosure, and the vibration isolators.

6 Rating and Application

6.1 Rating Category

6.1.1 The ISO 8528-1 rating category of the set shall be as indicated in the datasheet.
ISO 8528-1 Rating Categoryselect
Emergency standby power (ESP)
Prime rated power (PRP)
Limited-time running power (LTP)
Continuous operating power (COP)
Derived — the duty assigned to the set under the emergency and standby power standard, in accordance with ISO 8528-1 (by default)
6.1.2 A set that runs only while the normal source is lost, with a variable load and a limited number of hours in a year, shall be rated at emergency standby power.
6.1.3 A set that is the principal source for a variable load without a limit on annual hours shall be rated at prime rated power.
6.1.4 A set that is the principal source for a constant load for a limited number of hours in a year shall be rated at limited-time running power.
6.1.5 A set that carries a constant load without a limit on annual hours shall be rated at continuous operating power.
NOTE The four ratings are four outputs of the same engine, ordered from the highest to the lowest: the emergency standby rating is the most power the engine can be asked for, on the condition that it is asked rarely and the average load stays below the limit ISO 8528-1 sets; the prime and continuous ratings are lower because the engine is expected to deliver them for its life. A set rated at prime or continuous power for a duty that is standby carries a larger engine than the load needs, and a set rated at standby power for a duty that is prime wears out early. (6.1.6)

6.2 Rated Output

6.2.1 The site-rated output of the set at its rating category shall be as indicated in the datasheet.
Site-Rated Outputrange
kW
10152025304050608010012515017520025030035040050060075080010001250150017502000225025003000
Per drawings — the one-line diagram (deferred by default)
6.2.2 The rated output shall be the output at the site conditions, after the ambient and altitude corrections, and on the fuel selected under this standard; where the datasheet selects a dual-fuel engine, the rated output shall be met on each fuel unless the one-line diagram states a separate rating for each.
6.2.3 The rated power factor shall be 0.8 lagging for a three-phase set and 1.0 for a single-phase set, in accordance with ISO 8528-1, and the alternator shall carry the rated kilowatts at that power factor and at the temperature rise selected under this standard.
6.2.4 The capacity the alternate source must carry at each load step, including the starting of the largest motor and the sequence in which the transfer switches pick up their loads, is established under Emergency And Standby PowerEmergency and Standby Power SystemsResolves to the current adopted revision.sync/emergency-and-standby-power, and the rated output selected here shall be not less than that capacity.

6.3 Voltage, Phase, and Frequency

6.3.1 The rated voltage and winding configuration of the alternator shall be as indicated in the datasheet.
Rated Voltage and Configurationselect
120/240 V, 1Φ, three-wire
208Y/120 V, 3Φ, four-wire
240 V, 3Φ, three-wire
240/120 V, 3Φ, four-wire high-leg delta
480Y/277 V, 3Φ, four-wire
480 V, 3Φ, three-wire
600Y/347 V, 3Φ, four-wire
600 V, 3Φ, three-wire
Per drawings — the one-line diagram (deferred by default)
6.3.2 The rated voltage shall match the alternate-source terminals of the transfer switch selected under Automatic Transfer SwitchesAutomatic Transfer SwitchesResolves to the current adopted revision.sync/automatic-transfer-switches and the distribution the switch serves.
6.3.3 The rated frequency of the set shall be as indicated in the datasheet.
Rated Frequencyradio
● 60 Hz
○ 50 Hz
6.3.4 The rated speed of the set shall be as indicated in the datasheet.
Rated Speedrange
rpm
100012001500180030003600
6.3.5 The rated speed shall be a synchronous speed of the alternator at the rated frequency.
NOTE A four-pole alternator turns 1800 rpm at 60 Hz and 1500 rpm at 50 Hz, and a four-pole set is the construction of nearly every liquid-cooled set from a few tens of kilowatts to several megawatts, which is why 1800 rpm carries the default; a two-pole set at 3600 rpm is a small air-cooled or light-duty construction with a shorter engine life, and a six-pole set at 1200 rpm is a large, slow-speed engine bought for its life and its low sound. A project that selects 50 Hz corrects the speed to the four-pole or six-pole value at that frequency. (6.3.6)

6.4 Dynamic Performance

6.4.1 The ISO 8528-5 performance class of the set shall be as indicated in the datasheet.
ISO 8528-5 Performance Classselect
G1
G2
G3
G4
NOTE ISO 8528-5 groups the steady-state and transient voltage and frequency limits of a set into four classes: G1 for loads that need only basic voltage and frequency, G2 for loads that expect the voltage and frequency behavior of a public utility, G3 for loads that place severe demands on frequency, voltage, and waveform, including telecommunications equipment and thyristor-controlled loads, and G4 for limits agreed between the purchaser and the manufacturer. The class follows from the most sensitive load the set serves, so no class is the norm across projects. (6.4.2)
6.4.3 The maximum transient voltage deviation on the largest single load step shall be as indicated in the datasheet.
Transient Voltage Deviation on the Largest Load Steprange
% of rated voltage
510152025303540
6.4.4 The step-load analysis submitted under this standard shall demonstrate that the transient voltage deviation on the largest single step, and the recovery time to the steady-state band of the performance class, are within the limits selected, with the largest step taken from the load steps established under Emergency And Standby PowerEmergency and Standby Power SystemsResolves to the current adopted revision.sync/emergency-and-standby-power.
6.4.5 Where the analysis shows that the limits cannot be met with the alternator the manufacturer matches to the engine, the manufacturer shall propose an oversized alternator under the alternator sizing article of this standard, and shall not propose a larger engine to correct a voltage deviation.
NOTE The voltage dip on a motor start is set by the alternator's reactance and its excitation response, and the frequency dip is set by the engine's torque reserve and the governor, so a set that meets the voltage limit and misses the frequency limit needs a different engine or a smaller step, and a set that meets the frequency limit and misses the voltage limit needs a larger alternator on the same engine. (6.4.6)

7 Engine

7.1 Engine Construction

7.1.1 The engine shall be a four-stroke, liquid-cooled, reciprocating internal combustion engine, rated by the engine manufacturer for stationary generator service at the rating category selected under this standard, with its power declared in accordance with ISO 3046-1.
7.1.2 The engine aspiration shall be as indicated in the datasheet.
Engine Aspirationradio
○ Naturally aspirated
○ Turbocharged
○ Turbocharged and aftercooled
Manufacturer's standard (by default)
NOTE The aspiration is fixed by the engine the manufacturer matches to the rated output, so the manufacturer's selection is acceptable, and the field exists so that a project that needs a naturally aspirated engine for altitude or a turbocharged engine for a step-load requirement can record it. (7.1.3)
7.1.4 The engine shall be furnished with a full-flow lube oil filter with a replaceable element, a lube oil cooler where the engine manufacturer requires one, a thermostatically controlled coolant circuit, a coolant drain, an oil drain extended to the edge of the base with a valve, and a dry-type combustion air cleaner with a restriction indicator.
7.1.5 The engine shall be furnished with an electronic engine control unit that governs fuel delivery and reports oil pressure, coolant temperature, speed, and fault codes to the set controller.

7.2 Engine Fuel

7.2.1 The engine fuel shall be as indicated in the datasheet.
Engine Fuelradio
○ Diesel
○ Natural gas
○ Propane
○ Bi-fuel
○ Dual-fuel
NOTE No fuel is the norm across projects. Diesel stores its energy on the site in a tank whose contents are known, which is why it is chosen where the runtime must not depend on a gas utility and where the Authority Having Jurisdiction requires an on-site supply for a Level 1 system; natural gas needs no tank, no fuel quality program, and no spill containment, and is chosen where the gas service is reliable through the events that take the normal source down and the authority accepts it; propane stores on the site like diesel and burns like natural gas, at the cost of a vapor supply that falls with the tank temperature; bi-fuel keeps a diesel engine and displaces most of its diesel with natural gas while it runs, extending the tank; and dual-fuel is a spark-ignition engine that runs on natural gas or propane as selected at the set. (7.2.2)
7.2.3 The fuel selected shall satisfy the alternate source availability basis established under Emergency And Standby PowerEmergency and Standby Power SystemsResolves to the current adopted revision.sync/emergency-and-standby-power, and where that basis requires an on-site supply the fuel shall be diesel, propane, or bi-fuel with the runtime derived under this standard provided on the stored fuel alone.
NOTE The requirements in the fuel articles that follow apply where the datasheet selects the fuel each article names, and the requirements of two articles apply to a bi-fuel or dual-fuel set. (7.2.4)

7.3 Diesel Fuel Requirements

7.3.1 Where the datasheet selects diesel, the engine shall be a compression-ignition engine rated for ultra-low-sulfur No. 2-D diesel fuel in accordance with ASTM D975.
7.3.2 Where the datasheet selects diesel, the engine shall be furnished with a primary fuel filter and water separator with a water-in-fuel sensor wired to the controller, a secondary fuel filter, an engine-driven lift pump, and flexible fuel supply and return connections at the edge of the base.
7.3.3 Where the datasheet selects diesel, the engine shall accept a fuel blend containing biodiesel up to the percentage the engine manufacturer certifies, and the manufacturer shall state that percentage in the product data.
7.3.4 Where the datasheet selects diesel, the operation and maintenance data shall include a fuel quality program giving the sampling interval, the tests for water, particulates, and microbial growth, and the conditions under which the fuel is to be polished or replaced.
NOTE Diesel fuel in a standby tank ages for years between refills, absorbs water from the tank breathing, and grows microbial colonies at the fuel-water interface, so a set that starts on every monthly exercise can still fail on the day the filter plugs with the sludge of an unmanaged tank. (7.3.5)

7.4 Natural Gas Requirements

7.4.1 Where the datasheet selects natural gas, the engine shall be a spark-ignition engine rated for pipeline natural gas at the heating value and methane number the manufacturer states in the product data.
7.4.2 Where the datasheet selects natural gas, the Contractor shall confirm that Site Natural Gas ServiceSite Natural Gas ServiceParameterEach project supplies its own value.site-natural-gas-service delivers the inlet pressure and the full-load fuel flow the engine requires at the engine gas train with every other gas appliance on the service operating, and shall report any shortfall to the Engineer of Record before the set is released for manufacture.
7.4.3 Where the datasheet selects natural gas, the gas train shall be mounted on the set, listed as part of the UL 2200 assembly, and terminated at a single connection at the edge of the base, and shall include a manual shutoff valve, a strainer, a pressure regulator, two automatic safety shutoff valves in series that close on engine shutdown and on loss of control power, a low gas pressure switch and a high gas pressure switch wired to the controller, a test port for the supply pressure at the engine inlet, and a flexible connector at the engine, in accordance with NFPA 37 and NFPA 54.
7.4.4 Where the datasheet selects natural gas, the supply piping to the gas train connection shall be furnished under Fuel Gas PipingFacility Liquefied-Petroleum and Fuel Gas PipingResolves to the current adopted revision.sync/fuel-gas-piping and sized for the full-load flow at the lowest supply pressure the utility guarantees.
NOTE A gas engine that receives the pressure it needs at no load and not at full load runs on the exercise and stalls on the outage, because the pressure at the engine falls as the flow rises through an undersized service or a regulator at the edge of its capacity; the confirmation clause exists because this is the most common cause of a failed acceptance test on a gas set. (7.4.5)

7.5 Propane Requirements

7.5.1 Where the datasheet selects propane, the engine shall be a spark-ignition engine rated for propane vapor at the heating value the manufacturer states in the product data.
7.5.2 Where the datasheet selects propane, the gas train on the set shall satisfy the natural gas article of this standard and NFPA 58, with the regulator and the safety shutoff valves rated for propane.
7.5.3 Where the datasheet selects propane, the supply shall be vapor withdrawal from the storage tank, and the Contractor shall confirm that the tank delivers the full-load vapor rate at Site Ambient Temperature MinimumSite Ambient Temperature MinimumParameterEach project supplies its own value.site-ambient-temperature-minimum for the runtime derived under this standard, or shall furnish a vaporizer sized for that rate.
NOTE Propane vaporizes at the surface of the liquid in the tank, and the rate at which it does so falls with the tank temperature and with the liquid level, so a tank that carries enough propane by volume can still starve the engine on a cold night near the end of its charge. (7.5.4)
7.5.5 Where the datasheet selects propane, the storage tank and its siting shall be furnished under Fuel Dispensing And Storage TanksFuel Storage TanksResolves to the current adopted revision.sync/fuel-dispensing-and-storage-tanks and NFPA 58, and the piping from the tank to the gas train under Fuel Gas PipingFacility Liquefied-Petroleum and Fuel Gas PipingResolves to the current adopted revision.sync/fuel-gas-piping.

7.6 Bi-Fuel and Dual-Fuel Requirements

7.6.1 Where the datasheet selects bi-fuel, the engine shall be a compression-ignition engine that satisfies the diesel article of this standard, fitted with a natural gas induction system listed as part of the UL 2200 assembly, and the gas train shall satisfy the natural gas article.
7.6.2 Where the datasheet selects bi-fuel, the set shall start and accept load on diesel alone, shall introduce natural gas only after the engine has reached the operating condition the manufacturer requires, and shall revert to full diesel operation automatically on loss of gas pressure, on a combustion fault, or on any condition outside the substitution limits, without interrupting the output.
7.6.3 Where the datasheet selects bi-fuel, the manufacturer shall state the diesel substitution rate at each load point in the product data, and the runtime derived under this standard shall be calculated on diesel alone.
7.6.4 Where the datasheet selects dual-fuel, the engine shall be a spark-ignition engine rated for natural gas and for propane, the gas train shall satisfy both the natural gas article and the propane article of this standard, and the fuel shall be selectable at the set by a means that changes the fuel map and the regulator setting together.
7.6.5 Where the datasheet selects dual-fuel, the manufacturer shall state the rated output on each fuel in the rating statement.

7.7 Emissions

7.7.1 The federal emissions rule under which the engine is certified shall be as indicated in the datasheet.
Federal Emissions Ruleselect
40 CFR 60 Subpart IIII, emergency stationary compression-ignition engine
40 CFR 60 Subpart IIII, non-emergency stationary compression-ignition engine
40 CFR 60 Subpart JJJJ, emergency stationary spark-ignition engine
40 CFR 60 Subpart JJJJ, non-emergency stationary spark-ignition engine
Derived — the ignition type that follows from the fuel selected under this standard, and whether the set is applied as an emergency or a non-emergency stationary engine under the duty assigned by the emergency and standby power standard (by default)
7.7.2 The nonroad emissions tier to which a compression-ignition engine is certified shall be as indicated in the datasheet.
Compression-Ignition Engine Emissions Tierselect
Tier 2
Tier 3
Tier 4 Interim
Tier 4 Final
Not applicable, spark-ignition engine
Derived — the emissions rule derived under this standard, the displacement and the site-rated output of the engine furnished, and the model year, under the tier table 40 CFR 60 Subpart IIII applies to emergency and to non-emergency engines by reference to 40 CFR Part 1039 (by default)
7.7.3 The engine shall be certified under the rule and to the tier derived, and the certificate shall be delivered with the action submittals.
NOTE The tier is not a choice: 40 CFR 60 Subpart IIII assigns an emergency compression-ignition engine the nonroad tier that applied to its power band in its model year, which for an emergency engine stops short of the aftertreatment-based Tier 4 Final standards, and assigns a non-emergency engine the current tier, which for most power bands is Tier 4 Final with aftertreatment; a spark-ignition engine is certified to the emission limits of Subpart JJJJ rather than to a tier. Whether the engine is emergency or non-emergency is decided by the duty the system assigns, not by the set. (7.7.4)
7.7.5 Where the air quality authority applies a limit stricter than the federal rule, or a state rule requires a non-emergency certification for an emergency engine, the stricter requirement shall govern, and the Contractor shall report it to the Engineer of Record before the set is released for manufacture.
7.7.6 The engine shall comply with 40 CFR 63 Subpart ZZZZ for its operation and maintenance, and the operation and maintenance data shall state the recordkeeping the rule requires of the Owner.
7.7.7 The operation and maintenance data shall state the annual run-hour limits the emissions rule and the air permit impose on an emergency engine, including the limit on maintenance checks and readiness testing and the smaller allowance within it for other non-emergency operation.
NOTE An emergency engine is permitted unlimited hours in an actual emergency and a limited number of hours for maintenance and readiness testing, and an Owner who runs the set for load management, peak shaving, or an extended exercise beyond the allowance has re-classified it as a non-emergency engine, which it was not certified to be. (7.7.8)

8 Alternator

8.1 Alternator Construction

8.1.1 The alternator shall be a brushless, salient-pole, synchronous machine with a rotating field, complying with NEMA MG 1 and ISO 8528-3, directly coupled to the engine flywheel through a flexible coupling or a flexible disc, on a common skid with the engine.
8.1.2 The alternator shall be single-bearing or two-bearing as the manufacturer's construction for the frame provides, and shall not be belt-driven.
8.1.3 The stator winding shall be a two-thirds pitch winding, so that the third-harmonic voltage between the neutral and ground is suppressed and the neutral current from nonlinear loads is limited.
8.1.4 The alternator shall be furnished with a resistance temperature detector or thermistor in the stator winding wired to the controller where the site-rated output is 500 kW or more.

8.2 Excitation

8.2.1 The excitation system of the alternator shall be as indicated in the datasheet.
Excitation Systemradio
○ Permanent magnet generator excitation
○ Auxiliary winding excitation
○ Shunt excitation
NOTE A permanent magnet generator and an auxiliary winding each supply the voltage regulator from a source that is independent of the output voltage, so the field can be forced during a fault and during a motor start; a shunt-excited alternator draws its excitation from its own output, so its field collapses as the output voltage collapses into a bolted fault. Permanent magnet and auxiliary winding excitation are both standard constructions across the output range, so neither carries a default. (8.2.2)
8.2.3 Unless the datasheet selects shunt excitation, the excitation system shall sustain not less than 300 percent of rated current for not less than 10 seconds on a three-phase fault at the alternator terminals, so that the downstream overcurrent devices coordinated under Protective Coordination StudyProtective Device Coordination StudyResolves to the current adopted revision.sync/protective-coordination-study clear the fault before the field is removed.
8.2.4 Where the datasheet selects shunt excitation, the Contractor shall confirm under Protective Coordination StudyProtective Device Coordination StudyResolves to the current adopted revision.sync/protective-coordination-study that every overcurrent device the set feeds clears a fault within the decrement of the alternator furnished, and shall report to the Engineer of Record any device that does not.

8.3 Insulation and Temperature Rise

8.3.1 The alternator winding insulation class under NEMA MG 1 shall be as indicated in the datasheet.
Alternator Insulation Classradio
○ Class F
● Class H
8.3.2 The temperature rise of the alternator winding at the site-rated output, above the 40°C reference ambient of NEMA MG 1, shall not exceed the value indicated in the datasheet.
Alternator Winding Temperature Riserange
°C
80105125150
NOTE The insulation class states the temperature the winding survives, and the temperature rise states how close to it the set will run at its rated output; NEMA MG 1 permits a higher rise for standby duty than for continuous duty on the same class, and a winding run at a rise below what its class permits lasts longer, for a larger frame. The rise selected is therefore a trade between winding life and alternator size that depends on the duty and the hours expected, and it carries no default. (8.3.3)
NOTE The alternator insulation classes in this standard are the NEMA MG 1 rotating-machine letter classes, which remain the correct US designation for generator windings. (8.3.4)

8.4 Voltage Regulation

8.4.1 The voltage regulator shall be electronic, with three-phase root-mean-square sensing, and shall hold the steady-state voltage within the band indicated in the datasheet from no load to the site-rated output and from 0.8 lagging to unity power factor.
Steady-State Voltage Regulationrange
± % of rated voltage
0.51235
Default: Not more than 0.5 ± % of rated voltage
NOTE A band of ±0.5 percent is what an electronic regulator with three-phase sensing holds as a matter of course, which is why it carries the default; a wider band is selected where the performance class permits it and the regulator furnished is a simpler construction. (8.4.2)
8.4.3 The voltage regulator shall include an underfrequency roll-off that reduces the voltage in proportion to frequency below an adjustable knee, an overvoltage limit, an overexcitation limit, and a voltage adjustment of not less than ±5 percent at the controller.
8.4.4 Where the set is furnished with a governor that supports droop for paralleling, the voltage regulator shall include reactive droop compensation and a paralleling provision, and the paralleling itself shall be furnished under Generator Paralleling SwitchgearGenerator Paralleling SwitchgearResolves to the current adopted revision.sync/generator-paralleling-switchgear.

8.5 Alternator Sizing for Motor Starting

8.5.1 The basis on which the alternator frame is selected shall be as indicated in the datasheet.
Alternator Sizing Basisradio
○ Standard-frame alternator
○ Oversized alternator for motor starting
Manufacturer's standard (by default)
NOTE The manufacturer matches an alternator frame to each engine at its rating, and that frame is acceptable wherever the step-load analysis meets the transient voltage deviation selected under this standard; an oversized alternator on the same engine has a lower subtransient reactance and a lower voltage dip on a motor start, at the cost of a higher available fault current that the downstream equipment must be rated to withstand and interrupt. (8.5.2)
8.5.3 The manufacturer shall state the subtransient reactance and the decrement curve of the alternator furnished in the action submittals, whichever sizing basis applies.
8.5.4 Where an oversized alternator is furnished, the Contractor shall report the increased available fault current to the Engineer of Record so that the ratings established under Short Circuit StudyShort-Circuit StudyResolves to the current adopted revision.sync/short-circuit-study can be confirmed before the downstream equipment is released for manufacture.
8.5.5 Whether an anti-condensation heater is furnished in the alternator shall be as indicated in the datasheet.
Alternator Anti-Condensation Heaterradio
○ Not furnished
○ Furnished
8.5.6 An anti-condensation heater shall be furnished in the alternator of every set installed outdoors or in a space that is not conditioned, unless the datasheet selects an alternator without one and the Engineer of Record accepts the omission in writing.

9 Governor and Controller

9.1 Governor

9.1.1 The engine governor shall be as indicated in the datasheet.
Engine Governorradio
● Electronic isochronous
○ Electronic with selectable droop
○ Mechanical
NOTE An isochronous governor returns the frequency to its set point after every load change, so the frequency at steady state is the same at no load and at full load; a droop governor lets the frequency fall with load, which is what two sets need in order to share load on a common bus and what a single set serving a building does not need; a mechanical governor is a construction of small sets that holds the frequency within a wider band. An isochronous electronic governor is the construction of nearly every liquid-cooled set applied as a single source, which is why it carries the default. (9.1.2)
9.1.3 The governor shall hold the steady-state frequency within the band of the performance class selected under this standard, and shall return the frequency to that band within the recovery time of that class after the largest load step.
9.1.4 The governor shall include an overspeed shutdown independent of the speed control, set at the value the engine manufacturer specifies, wired to the controller.

9.2 Controller Functions

9.2.1 The set shall be furnished with a microprocessor-based controller, listed as part of the UL 2200 assembly, mounted on the set on vibration isolators, with a display readable from the normal service position and an interface at which every setting can be read and changed.
9.2.2 The controller shall provide automatic starting on a remote start signal, cranking with a programmable crank and rest cycle and an overcrank limit, a programmable warm-up before load acceptance where the type time permits one, a programmable cool-down run after the load is removed, and automatic shutdown at the end of the cool-down.
9.2.3 The controller shall provide alternating-current metering of voltage on each phase, current on each phase, frequency, kilowatts, kilovolt-amperes, kilovolt-amperes reactive, power factor, and kilowatt-hours, and engine metering of oil pressure, coolant temperature, battery voltage, speed, fuel level, and run hours.
9.2.4 The controller shall retain every setting and an event log of not fewer than 100 events with date and time stamps in non-volatile memory through loss of the battery.
9.2.5 Changes to settings at the controller shall be protected by a password or a keyed switch so that a setting cannot be changed by an unauthorized person.
9.2.6 The controller shall provide an off, manual run, and automatic mode selection, and shall raise a not-in-automatic alarm at the controller and at the remote annunciator whenever the mode is not automatic.
9.2.7 The controller display shall be as indicated in the datasheet.
Controller Displayselect
Alphanumeric display with status indicators
Graphical display with menu navigation
Color touchscreen
Manufacturer's standard (by default)
NOTE The display does not affect the function of the set, and every listed controller gives local access to the metering, the alarms, and the settings, so the manufacturer's offering is acceptable unless the Owner's operating program calls for one interface across its equipment. (9.2.8)

9.3 NFPA 110 Alarms and Shutdowns

9.3.1 Where the set serves a system classified under NFPA 110, the controller shall provide every alarm, pre-alarm, and shutdown the alarm and annunciation table of NFPA 110 Chapter 5 requires for the level assigned under Emergency And Standby PowerEmergency and Standby Power SystemsResolves to the current adopted revision.sync/emergency-and-standby-power, and shall annunciate each at the controller and at the remote annunciator.
NOTE The alarm and shutdown set is fixed by the level the system assigns, so it is stated here as a requirement and not offered as a selection at the set. (9.3.2)
9.3.3 The controller shall shut the engine down on overspeed, on low oil pressure, on high coolant temperature, on overcrank, and on operation of the emergency stop, and shall not shut the engine down on any other engine condition while the set serves a Level 1 system except as NFPA 110 permits.
NOTE A Level 1 set is required to keep running through conditions that would shut a prime-power set down, because the life-safety load it carries is worth more than the engine; NFPA 110 therefore limits the shutdowns to the few that protect against immediate destruction and requires everything else to be a pre-alarm. (9.3.4)
9.3.5 The controller shall provide a low fuel pre-alarm at the fuel level the system's runtime class requires under NFPA 110, a low coolant level alarm, a low coolant temperature alarm, a low battery voltage alarm, a high battery voltage alarm, and a battery charger malfunction alarm, in addition to the engine shutdowns.

9.4 Remote Annunciator

9.4.1 Where the set serves a system classified as Level 1 under NFPA 110, a remote annunciator shall be furnished at a location that is continuously attended, as indicated on the electrical plans.
9.4.2 The remote annunciator shall display every alarm, pre-alarm, and shutdown the controller provides under this standard, the set running condition, the not-in-automatic condition, and the position of each transfer switch wired to it under Automatic Transfer SwitchesAutomatic Transfer SwitchesResolves to the current adopted revision.sync/automatic-transfer-switches, with a common audible alarm, a silence control, and a lamp test.
9.4.3 The communication path between the controller and the remote annunciator shall be as indicated in the datasheet.
Remote Annunciator Communication Pathradio
○ Hardwired from the controller
○ Network connection from the controller
9.4.5 Where the datasheet selects a network connection, the network equipment between the controller and the annunciator shall be supplied from the alternate source, so that the annunciator continues to report while the normal source is lost.
NOTE A hardwired path is a pair of conductors in a raceway that carries the annunciation whether or not any network is up; a network path carries the same points over the building network and adds the points to the monitoring platform at once, at the cost of a path whose availability during an outage depends on every switch between the two ends. Neither is the norm across projects. (9.4.6)

9.5 Communications

9.5.1 The communications interfaces furnished at the controller shall be as indicated in the datasheet.
Controller Communications Interfacescheckbox
☐ Dry contacts only
☐ Modbus RTU serial
☐ Modbus TCP
☐ BACnet MS/TP
☐ BACnet/IP
☐ SNMP
☐ DNP3
☐ Proprietary protocol over Ethernet
NOTE The protocol follows from the monitoring platform the project uses, so the field carries no default; dry contacts are listed so that a set reporting only through contact closures is recorded as such rather than left blank. (9.5.2)
9.5.3 Where a protocol interface is furnished, the controller shall report at least the running condition, the mode, every alarm and shutdown, the alternating-current and engine metering, the fuel level, the run hours, and each event in its log, and the point list shall be coordinated with Building Automation SystemBuilding Automation SystemResolves to the current adopted revision.sync/building-automation-system.
9.5.4 The controller shall provide dry contacts for the set running, common alarm, common shutdown, not-in-automatic, and low fuel conditions, rated for the pilot duty of the circuits they serve, wired to terminal blocks that can be reached without exposing energized power conductors.

9.6 Engine Start Interface

9.6.1 The controller shall start the engine on closure of a two-wire remote start contact and shall stop it, after the cool-down run, on opening of that contact, and shall accept the engine-start contacts of every transfer switch furnished under Automatic Transfer SwitchesAutomatic Transfer SwitchesResolves to the current adopted revision.sync/automatic-transfer-switches in parallel.
9.6.2 The controller shall accept a three-wire start signal where the datasheet under Automatic Transfer SwitchesAutomatic Transfer SwitchesResolves to the current adopted revision.sync/automatic-transfer-switches selects a three-wire arrangement.
9.6.3 The remote start circuit shall be arranged so that loss of the control wiring between the transfer switch and the set, or loss of control power at the switch, calls for the engine to start.
9.6.4 Where the set serves an Article 700 emergency system, the remote start wiring between the transfer switch and the set shall be installed and separated in accordance with NEC 700.10, and where an Article 701 system, in accordance with NEC 701.10.

10 Output Protection and Neutral

10.1 Main Line Circuit Breaker

10.1.1 The overcurrent protection at the output of the set shall be as indicated in the datasheet.
Set Output Overcurrent Protectionradio
● One set-mounted main line circuit breaker
○ Two or more set-mounted main line circuit breakers
○ Overcurrent protection at the downstream distribution equipment with no set-mounted breaker
NOTE A set-mounted breaker gives the set the overload protection NEC 445.12 requires and a disconnecting means at the set, and it is the construction of nearly every packaged set, which is why it carries the default; more than one breaker is furnished where the set feeds more than one transfer switch directly, and a set without a breaker relies on the protection at the first downstream equipment and on the inherent design provisions NEC 445.12 permits. (10.1.2)
10.1.3 Where a set-mounted breaker is furnished, it shall be a molded-case or insulated-case circuit breaker listed as part of the UL 2200 assembly, rated for not less than the rated current of the alternator at the site-rated output and the rated power factor, mounted in an enclosure on the set, and accessible for operation and maintenance from the service side of the set.
10.1.4 Where a set-mounted breaker is furnished, the trip unit of the breaker shall be as indicated in the datasheet.
Main Line Breaker Trip Unitselect
Thermal-magnetic
Electronic with long-time, short-time, and instantaneous functions
Electronic with long-time, short-time, instantaneous, and ground-fault functions
Derived — the settings the protective device coordination study requires of the set breaker so that it coordinates with the transfer switch and the downstream devices (by default)
NOTE The trip unit follows from the coordination the system requires: where the set serves an Article 700, 701, or 708 system, NEC 700.32, 701.32, and 708.54 require the set breaker to coordinate selectively with every downstream device, which a thermal-magnetic trip achieves only on the smallest systems, so the trip unit is derived from Protective Coordination StudyProtective Device Coordination StudyResolves to the current adopted revision.sync/protective-coordination-study rather than selected at the set. (10.1.5)
10.1.6 The breaker shall be furnished with a shunt trip wired to the controller emergency stop circuit, and with auxiliary contacts indicating the breaker position wired to the controller and to the remote annunciator.
10.1.7 The breaker interrupting rating shall be not less than the available fault current at the set terminals from the alternator, as established under Short Circuit StudyShort-Circuit StudyResolves to the current adopted revision.sync/short-circuit-study with the reactances of the alternator furnished.

10.2 Ground-Fault Provisions

10.2.1 Where the set serves an Article 700 emergency system, is solidly grounded, operates at more than 150 V to ground, and has a set breaker rated 1000 A or more, the set shall be furnished with ground-fault indication at the set breaker in accordance with NEC 700.31, with the sensor located where the neutral bonding at the set places the fault current.
10.2.2 Where the set serves an Article 700 emergency system, the ground-fault provision at the set shall indicate and shall not trip the set breaker, in accordance with NEC 700.31.
10.2.3 Where the datasheet under this standard derives a trip unit with a ground-fault function for a set serving other than an Article 700 system, the ground-fault function shall be set to coordinate with the downstream ground-fault devices under Protective Coordination StudyProtective Device Coordination StudyResolves to the current adopted revision.sync/protective-coordination-study.
NOTE A ground fault on the emergency system during an outage is a fault the code chooses to tolerate rather than to clear, because clearing it de-energizes the egress lighting; the indication tells the Owner to find the fault, and the trip that would ordinarily follow is withheld. (10.2.4)

10.3 Neutral Bonding at the Set

10.3.1 Whether the alternator neutral is bonded to ground at the set shall be as indicated in the datasheet.
Neutral-to-Ground Bond at the Setradio
○ Bonded at the set, separately derived system
○ Not bonded at the set, not a separately derived system
Derived — the neutral treatment of the transfer switch selected under the automatic transfer switches standard, bonded at the set where the neutral is switched and not bonded where the neutral is solid (by default)
10.3.2 Where the neutral is bonded at the set, the set shall be a separately derived system, the system bonding jumper shall be installed at the set, and the grounding electrode connection shall be made in accordance with NEC 250.30 and Grounding And BondingGrounding and Bonding for Electrical SystemsResolves to the current adopted revision.sync/grounding-and-bonding.
10.3.3 Where the neutral is not bonded at the set, the manufacturer shall ship the set with the neutral isolated from the frame, the alternator neutral shall be carried to the transfer switch as an insulated conductor, and the Contractor shall confirm the absence of a neutral-to-ground bond at the set before the set is energized.
NOTE The bond exists at one point in a system and nowhere else. A set bonded at its neutral behind a switch whose neutral is solid puts a second bond on the system, and the neutral current then divides between the neutral conductor and the equipment grounding path; a set not bonded behind a switch whose neutral is switched leaves the load with no ground reference while it runs on the set. Either mismatch is a wiring error, so the bonding at the set is derived from the switch rather than decided here. (10.3.4)
10.3.5 The alternator frame, the engine, the enclosure, and the sub-base tank shall be bonded to the equipment grounding conductor of the feeder in accordance with NEC Article 250 and Grounding And BondingGrounding and Bonding for Electrical SystemsResolves to the current adopted revision.sync/grounding-and-bonding, whichever neutral bonding applies.

11 Cooling System

11.1 Cooling Arrangement

11.1.1 The cooling arrangement of the set shall be as indicated in the datasheet.
Cooling Arrangementradio
● Set-mounted radiator
○ Remote radiator
○ Heat exchanger with a remote heat rejection source
NOTE A set-mounted radiator with its fan on the engine is the construction of nearly every packaged set, needs no cooling connection beyond the air path, and rejects the engine heat wherever the set stands, which is why it carries the default; a remote radiator moves the heat rejection and its fan noise out of a room that cannot pass the air, at the cost of coolant piping and an electric fan; a heat exchanger rejects the engine heat to a building cooling loop or a cooling tower, at the cost of a source that must stay available through the outage. (11.1.2)
11.1.3 The cooling system shall reject the full-load heat of the engine, including the after-cooler and the lube oil cooler, at the site design ambient of this standard, with the coolant outlet temperature not less than 10°C below the engine manufacturer's limit.
11.1.4 Where the datasheet selects a remote radiator, the radiator shall be sized for the coolant flow and head the engine pump delivers through the piping, or shall be furnished with an auxiliary coolant pump, and the fan motor shall be supplied from the set output through a circuit that is energized whenever the engine runs.
11.1.5 Where the datasheet selects a heat exchanger, the heat rejection source shall satisfy the availability basis established under Emergency And Standby PowerEmergency and Standby Power SystemsResolves to the current adopted revision.sync/emergency-and-standby-power, and a source that depends on a utility that may fail in the same event as the normal source shall not be used for a set serving an Article 700 system unless the Authority Having Jurisdiction accepts it in writing.

11.2 Radiator and Fan

11.2.1 The radiator fan drive shall be as indicated in the datasheet.
Radiator Fan Driveradio
● Engine-driven
○ Electric motor-driven
11.2.2 The radiator shall be sized for the engine manufacturer's published heat rejection at the site design ambient, with the air temperature rise through the enclosure or the room added to the ambient, and with the external static pressure of the discharge duct or the enclosure louvers where either is furnished.
11.2.3 The radiator core shall be copper-brass or aluminum, and where the set is installed within 1 mile of a salt-water shoreline or in a corrosive atmosphere the core shall be copper-brass or shall carry a corrosion-resistant coating the manufacturer rates for that exposure.
11.2.4 The fan and every belt-driven accessory shall be fitted with guards that prevent contact from the service side of the set.
11.2.5 The radiator shall be furnished with a discharge flange for a duct connection where the set is installed indoors, and the duct shall carry the radiator discharge to the outdoors through an opening as indicated on the mechanical drawings.

11.3 Coolant

11.3.1 The engine coolant shall be as indicated in the datasheet.
Engine Coolantselect
Ethylene glycol and water
Propylene glycol and water
Extended-life organic acid technology coolant
Manufacturer's standard (by default)
NOTE The coolant is matched to the engine's wet liners, seals, and heater by the engine manufacturer, so the manufacturer's specified coolant is acceptable, and the field exists so that a project that requires propylene glycol for a food, pharmaceutical, or water-facility location can record it. (11.3.2)
11.3.3 The coolant shall be mixed to protect against freezing at Site Ambient Temperature MinimumSite Ambient Temperature MinimumParameterEach project supplies its own value.site-ambient-temperature-minimum where the set is installed outdoors or in a space that follows the outdoor temperature, and against freezing at the lowest temperature of the room where the set is installed indoors.
11.3.4 The cooling system shall be furnished with a coolant recovery bottle, a low coolant level sensor wired to the controller, a coolant drain valve, and a coolant heater connection where a jacket water heater is furnished.

12 Fuel System on the Skid

12.1 Diesel Fuel Storage Arrangement

12.1.1 Where the datasheet selects diesel or bi-fuel, the fuel storage arrangement at the set shall be as indicated in the datasheet.
Diesel Fuel Storage Arrangement at the Setradio
○ Sub-base tank
○ Sub-base tank with automatic make-up from remote bulk storage
○ Day tank at the set fed from remote bulk storage
○ Direct supply from remote bulk storage without a day tank
NOTE A sub-base tank carries the set's fuel in its own base and is bought with the set, so the fuel system is complete at the skid connection and the runtime is fixed by the tank the base can hold; a remote bulk tank stores more fuel than a base can carry, feeds a day tank or a sub-base tank at the set through a transfer system, and moves the storage away from the set, at the cost of pumps, controls, and piping furnished under Fuel Oil SystemsFacility Fuel-Oil SystemsResolves to the current adopted revision.sync/fuel-oil-systems. The arrangement follows from the runtime and from where the fuel can be stored, so no arrangement is the norm across projects. (12.1.2)
12.1.3 Where the datasheet selects a day tank or make-up from remote bulk storage, the transfer pumps, the day-tank level controls, the overflow return, and the supply and return piping shall be furnished under Fuel Oil SystemsFacility Fuel-Oil SystemsResolves to the current adopted revision.sync/fuel-oil-systems, and the day tank as a vessel under Fuel Dispensing And Storage TanksFuel Storage TanksResolves to the current adopted revision.sync/fuel-dispensing-and-storage-tanks.
12.1.4 Where the datasheet selects direct supply from remote bulk storage, the engine lift pump shall be rated for the suction lift and the line length to the bulk tank, or a transfer pump shall be furnished under Fuel Oil SystemsFacility Fuel-Oil SystemsResolves to the current adopted revision.sync/fuel-oil-systems.

12.2 Runtime and Tank Capacity

12.2.1 The runtime the fuel stored at the set shall provide at the site-rated output shall be as indicated in the datasheet.
Fuel Runtime at the Site-Rated Outputrange
hours
124681224487296168
Derived — the NFPA 110 class assigned to the system under the emergency and standby power standard, or the runtime the Owner requires of a system outside NFPA 110 (by default)
12.2.2 The usable capacity of the sub-base tank or the day tank at the set shall be as indicated in the datasheet.
Usable Fuel Capacity at the Setrange
gal
255010015020030040050075010001500200025003000400050006000
Derived — the runtime derived under this standard, the fuel consumption of the set furnished at the site-rated output, and the unusable volume and fill limit the tank listing imposes (by default)
NOTE The runtime is a property of the system, fixed by the class NFPA 110 assigns it, and the tank capacity follows from the runtime and from how much fuel the engine furnished burns at full load, so neither is decided at the set; the fuel consumption table in the action submittals is the document that closes the calculation. (12.2.3)
12.2.4 Where the datasheet selects a day tank fed from remote bulk storage, the runtime derived under this standard shall be provided by the bulk storage under Fuel Oil SystemsFacility Fuel-Oil SystemsResolves to the current adopted revision.sync/fuel-oil-systems and the day tank capacity shall be the capacity the day-tank controls and the transfer system require.
12.2.5 Where the datasheet selects a sub-base tank with automatic make-up, the runtime derived under this standard shall be provided by the sub-base tank and the bulk storage together, and the sub-base tank alone shall provide not less than the runtime the Engineer of Record establishes for operation with the transfer system out of service.

12.3 Sub-Base Tank

12.3.1 Where a sub-base tank is furnished, it shall be furnished by the generator manufacturer as part of the UL 2200 assembly, shall carry the weight of the set with the vibration isolators between the set and the tank, and shall be listed to UL 142 or UL 2085 with the construction, containment, venting, overfill prevention, and leak detection selected under Fuel Dispensing And Storage TanksFuel Storage TanksResolves to the current adopted revision.sync/fuel-dispensing-and-storage-tanks.
12.3.2 The sub-base tank shall be furnished with a fuel level sender wired to the controller, a low fuel pre-alarm contact at the level required under this standard, a fill connection with overfill protection reachable without entering the enclosure, normal and emergency vents terminated as NFPA 30 requires, a fuel supply outlet with a shutoff valve, a fuel return connection, and a drain.
12.3.3 The sub-base tank shall be furnished with a leak detection sensor in the interstitial space wired to the controller and annunciated as an alarm where the tank is of double-wall construction.
12.3.4 The height the sub-base tank adds to the set shall be shown on the shop drawings, and the Contractor shall confirm before the set is released for manufacture that the set with its tank passes through every opening on the delivery path and that the fill connection and the controller remain reachable from grade.

12.4 Engine Fuel Piping and Filtration

12.4.1 Fuel piping on the skid between the tank or the skid connection and the engine shall be steel or the material the engine manufacturer furnishes, with flexible connectors at the engine, and shall satisfy NFPA 37 and NFPA 30.
12.4.2 A fuel return cooler shall be furnished where the engine manufacturer requires one to hold the return fuel below the temperature the tank and the injection system permit.
12.4.3 The primary fuel filter and water separator furnished under the diesel article of this standard shall have its drain reachable from the service side of the set.

13 Exhaust System

13.1 Silencer

13.1.1 The exhaust silencer grade shall be as indicated in the datasheet.
Exhaust Silencer Gradeselect
Industrial
Residential
Critical
Hospital
Super-critical
NOTE Silencer grades are named by the industry for the insertion loss they provide, from an industrial grade of roughly 12 to 18 dB through residential and critical grades to a hospital grade of roughly 25 to 35 dB and a super-critical grade above that; the grade follows from the sound level selected under this standard and from the share of the set's sound that leaves through the exhaust rather than through the enclosure, so no grade is the norm across projects. (13.1.2)
13.1.3 The silencer shall be sized for the full-load exhaust flow of the engine at a back pressure that, with the exhaust piping and the aftertreatment, does not exceed the engine manufacturer's allowable back pressure at full load.
NOTE Excess back pressure raises the exhaust temperature, reduces the power, and shortens the life of the turbocharger and the valves, so the allowable back pressure is a limit the silencer, the piping, and the aftertreatment share. (13.1.4)
13.1.5 The silencer shall be mounted on the set inside the enclosure where the enclosure is furnished, and on isolated supports clear of the engine where the set is an open set, with a flexible exhaust connection between the engine outlet and the silencer.

13.2 Exhaust Piping

13.2.1 The exhaust pipe material shall be as indicated in the datasheet.
Exhaust Pipe Materialradio
● Carbon steel, Schedule 40
○ Carbon steel, Schedule 80
○ Stainless steel
13.2.2 Where the exhaust condensate cannot be drained before it reaches a horizontal run, or where the set is installed in a corrosive atmosphere, the exhaust piping shall be stainless steel.
13.2.3 The extent of exhaust pipe insulation shall be as indicated in the datasheet.
Exhaust Pipe Insulationradio
○ Insulated throughout inside the building and inside the enclosure
○ Insulated where within reach of personnel or within the clearance to combustibles
○ Not insulated
13.2.4 Exhaust piping shall be insulated where it passes within the clearance to combustible construction NFPA 37 requires, whichever extent the datasheet selects.
13.2.5 The exhaust shall be routed with welded or flanged joints, supported clear of the engine so that no exhaust load bears on the engine outlet, and terminated with a rain cap or a rain-shedding elbow at a point from which the exhaust cannot re-enter the building, the combustion air, or the cooling air, in accordance with NFPA 37, and the routing shall be as indicated on the mechanical drawings.
13.2.6 Where the exhaust passes through a wall or a roof, it shall pass through a listed thimble sized for the pipe and its insulation, with the clearance to combustibles the thimble listing requires.
13.2.7 A condensate trap and drain shall be furnished at every low point of the exhaust that can collect condensate, and the drain shall discharge to a waste connection that accepts an acidic condensate and not onto building materials or into a storm drain.

13.3 Aftertreatment

13.3.1 The exhaust aftertreatment furnished with the engine shall be as indicated in the datasheet.
Exhaust Aftertreatmentcheckbox
☐ None
☐ Diesel oxidation catalyst
☐ Diesel particulate filter
☐ Selective catalytic reduction with diesel exhaust fluid
☐ Three-way catalyst
Derived — the emissions rule and tier derived under this standard and the certification pathway of the engine furnished (by default)
13.3.2 Where aftertreatment is furnished, it shall be furnished by the generator manufacturer as part of the exhaust system, with its sensors, its controller, and, for selective catalytic reduction, the diesel exhaust fluid tank, the dosing system, and the fluid heater, and the assembly shall be certified with the engine.
13.3.3 Where aftertreatment is furnished, it shall be located so that the exhaust temperature at its inlet stays above the temperature the catalyst needs during the operating cycle the duty imposes, and the operation and maintenance data shall state the loading at which the exhaust reaches that temperature.
NOTE Aftertreatment that never gets hot does nothing, and a diesel particulate filter that never regenerates plugs; a standby set that exercises at light load can fail its own emissions device, which is why the loading the device needs is a maintenance instruction and not a footnote. (13.3.4)

14 Enclosure and Sound

14.1 Installation Configuration

14.1.1 The installation configuration of the set shall be as indicated in the datasheet.
Installation Configurationselect
Open set for indoor installation
Weather-protective enclosure
Sound-attenuated enclosure
Walk-in sound-attenuated enclosure
NOTE An open set is installed in a room that provides the weather protection, the ventilation, the fire separation, and the sound attenuation, and every one of those becomes a building cost; a weather-protective enclosure is a housing that keeps the rain off an outdoor set and nothing more; a sound-attenuated enclosure adds acoustic lining, attenuated intake and discharge openings, and an integrated silencer to meet a sound level; a walk-in enclosure adds the space to service the set inside it. The configuration follows from where the set stands and what sound level it must meet, so none is the norm across projects. (14.1.2)
14.1.3 Where the datasheet selects an open set, the room shall satisfy Electrical RoomsElectrical RoomsResolves to the current adopted revision.sync/electrical-rooms and the fire separation NFPA 110 Chapter 7 requires for the level assigned, and the ventilation and combustion air shall be as required under the ambient temperature article of this standard.
14.1.4 Where the datasheet selects an enclosure, the enclosure shall be listed as part of the UL 2200 assembly and shall be rated for the design wind speed as indicated on the structural drawings.

14.2 Control and Terminal Enclosures

14.2.1 The enclosure type of the controller, the breaker, and the terminal compartments on the set shall be as indicated in the datasheet.
Control and Terminal Enclosure Typeselect
NEMA Type 1
NEMA Type 3R
NEMA Type 4
NEMA Type 4X
NEMA Type 12
NOTE A set inside a weather-protective or sound-attenuated enclosure, and an open set in a dry indoor room, both place the controller and the breaker in a dry location, which is why Type 1 is the default; every other location named in the clauses of this article calls for the type those clauses require. (14.2.2)
14.2.3 Where the set is installed outdoors without an enclosure, or where the controller or the breaker is mounted on the exterior of the enclosure, the controller, breaker, and terminal compartments shall be Type 3R, Type 4, or Type 4X.
14.2.4 Where the set is installed where the atmosphere carries salt, chemical vapor, or another corrosive agent, the controller, breaker, and terminal compartments mounted outside the enclosure shall be Type 4X.
14.2.5 Where the set is installed indoors where airborne dust, lint, or fibers accumulate, the controller, breaker, and terminal compartments shall be Type 12, Type 4, or Type 4X.
14.2.6 Where a rating higher than the datasheet selection is required by the clauses of this article for the installed location, the higher rating shall be furnished and the conflict reported to the Engineer of Record before the set is released for manufacture.

14.3 Enclosure Construction

14.3.1 The enclosure material shall be as indicated in the datasheet.
Enclosure Materialradio
● Galvanized steel
○ Aluminum
○ Stainless steel
NOTE Galvanized steel with a powder-coat finish serves every location that is not corrosive, which is why it carries the default; aluminum resists salt air without a coating and is lighter, and stainless steel holds up where chemical vapor attacks both. (14.3.2)
14.3.3 Where the set is installed within 1 mile of a salt-water shoreline or in a corrosive atmosphere, the enclosure shall be aluminum or stainless steel, or galvanized steel with a coating system the manufacturer rates for that exposure, and the fasteners and hinges shall be stainless steel.
14.3.4 The enclosure shall be fabricated with welded or sealed seams, a finish of powder coat or a coating system of not less than the dry film thickness the manufacturer publishes for the exposure, lockable hinged doors on both sides giving access to the engine, the alternator, the controller, and the breaker, and a removable roof section or end panel for the removal of the engine or the alternator.
14.3.5 The enclosure shall be furnished with intake and discharge openings sized for the radiator air flow and the combustion air at the site design ambient, with rain hoods or louvers that exclude wind-driven rain and snow, with bird and rodent screens, and, where the datasheet selects a sound-attenuated enclosure, with attenuated openings and acoustic lining rated for moisture and fire.
14.3.6 Where motorized louvers are furnished, they shall open before cranking begins, shall fail open on loss of control power, and shall be proven open before the set accepts load.
14.3.7 A walk-in enclosure shall be furnished with interior lighting on a circuit from the set output, a convenience receptacle, a personnel door at each end with panic hardware, and a floor that drains to the outside.
14.3.8 Where the cold-start provisions derived under this standard include an enclosure heater, the enclosure shall be furnished with a thermostatically controlled heater sized to hold the interior above the temperature the battery and the controller require at Site Ambient Temperature MinimumSite Ambient Temperature MinimumParameterEach project supplies its own value.site-ambient-temperature-minimum.

14.4 Sound Level

14.4.1 The sound pressure level of the set at full load, measured at 7 m, shall not exceed the value indicated in the datasheet.
Sound Pressure Level at 7 m at Full Loadrange
dB(A)
5560656870727578808590
Per drawings — the generator schedule (deferred by default)
14.4.2 The sound pressure level shall be measured in accordance with ISO 8528-10 as the average of the positions the standard specifies around the set, at 7 m, in a free field, with the set at the site-rated output and the exhaust silencer and aftertreatment furnished in place.
NOTE The sound limit is fixed by the noise ordinance and by the nearest receptor, which are facts of the site, and engine generators have no consensus-standard sound table indexed to rating against which a relative limit could be written, so the limit is recorded on the generator schedule rather than selected in the template. (14.4.3)
14.4.4 The manufacturer shall state in the sound data the octave-band levels from which the A-weighted level is derived and the contribution of the exhaust outlet, so that the silencer grade and the enclosure can be checked against the limit separately.
14.4.5 Compliance at the property line or at a receptor, where the noise ordinance measures there, shall be demonstrated by the Engineer of Record from the 7 m data and the distance, the intervening barriers, and the reflections of the site, and is not a requirement placed on the set.

15 Starting System

15.1 Starter

15.1.1 The starting system of the engine shall be as indicated in the datasheet.
Starting Systemradio
● Electric
○ Pneumatic
NOTE An electric starter on a battery is the starting system of nearly every packaged set, which is why it carries the default; a pneumatic starter on a compressed air receiver is a construction of large engines and of installations where an air system already exists and a battery is not wanted. (15.1.2)
15.1.3 The starter shall be sized for the engine at the lowest temperature the cold-start provisions of this standard hold the engine to, and the controller shall limit cranking to the crank and rest cycle the engine manufacturer specifies with an overcrank shutdown at the end of the cycle.
15.1.4 Where the datasheet selects a pneumatic starter, the air receiver shall hold the volume for the cranking cycle NFPA 110 Chapter 5 requires without recharge, and the compressor shall be supplied from the normal source with an alarm on low receiver pressure wired to the controller.

15.2 Starting Batteries

15.2.1 Where the datasheet selects an electric starter, the starting battery type shall be as indicated in the datasheet.
Starting Battery Typeradio
○ Flooded lead-acid
○ Absorbed glass mat lead-acid
○ Nickel-cadmium
○ Lithium iron phosphate
NOTE A flooded lead-acid battery is the least costly and is what most sets ship with, and it needs watering and vents acid gas on charge; an absorbed glass mat battery is sealed, tolerates vibration, and needs no watering, for a higher price and a shorter life at high temperature; a nickel-cadmium battery holds its cranking capacity across the widest temperature range and the longest life, at the highest price; a lithium iron phosphate battery is the lightest and holds its voltage through the crank, and carries its own management system and charging requirements as part of its listing. No type is the norm across projects. (15.2.2)
15.2.3 The battery type furnished shall be one NFPA 110 Chapter 5 permits for the level assigned under Emergency And Standby PowerEmergency and Standby Power SystemsResolves to the current adopted revision.sync/emergency-and-standby-power, and where the type selected is not named there it shall be accepted by the Authority Having Jurisdiction in writing before the set is released for manufacture.
15.2.4 The battery shall be sized in accordance with EGSA 100B for the cranking cycle NFPA 110 Chapter 5 requires, at the lowest temperature the battery reaches with the battery warmer furnished under this standard in operation, and the manufacturer shall state the sizing basis in the product data.
15.2.5 The starting system voltage shall be as indicated in the datasheet.
Starting System Voltageradio
○ 12 V
○ 24 V
Manufacturer's standard (by default)
15.2.6 The starting voltage is fixed by the engine the manufacturer matches to the rated output, so the manufacturer's selection is acceptable, and the manufacturer shall state it in the product data.
15.2.7 The batteries shall be mounted on the set or in the enclosure in a rack that resists vibration and that holds the batteries clear of the engine heat, with the terminals protected from contact and the cables sized for the cranking current at the length installed.
15.2.8 A battery disconnect switch shall be furnished at the battery rack, reachable without opening the controller enclosure, so that the set can be made safe for service.

15.3 Battery Charger

15.3.1 A battery charger listed to UL 1236 shall be furnished on the set, with automatic float and equalize charging, temperature compensation, current limiting, reverse-polarity and short-circuit protection, and a direct-current ammeter and voltmeter.
15.3.2 The output rating of the battery charger shall be as indicated in the datasheet.
Battery Charger Output Ratingrange
A
25101520304050
15.3.3 Where the datasheet does not select a charger rating, the charger shall be rated for the recharge of a fully discharged battery within the time NFPA 110 Chapter 5 requires, at the charge rate the battery manufacturer recommends for the battery furnished, and the rating shall be stated in the product data.
15.3.4 The charger shall be powered from a dedicated branch circuit on the normal source, and shall be wired so that on loss of the normal source the charger is de-energized and the engine alternator carries the charging while the set runs.
15.3.5 The charger shall provide a charger malfunction contact, a low battery voltage contact, and a high battery voltage contact wired to the controller, in accordance with NFPA 110 Chapter 5.
15.3.6 Where the datasheet selects a lithium iron phosphate battery, the charger shall be one the battery manufacturer lists for the battery and its management system, and the charger and battery shall be furnished together.

16 Mounting, Vibration Isolation, and Anchorage

16.1 The vibration isolation of the set shall be as indicated in the datasheet.
Vibration Isolationradio
○ Isolators between the engine-alternator and the base
○ Isolators between the engine-alternator and the base, and restrained isolators between the base and the pad
○ Restrained spring isolators on an inertia base
Manufacturer's standard (by default)
NOTE Every packaged set carries isolators between the engine-alternator and its base or sub-base tank as the manufacturer's construction, and that is enough where the set stands on a pad outdoors or on grade with nothing occupied beneath it; a set inside an occupied building or on a framed floor puts its vibration into the structure through the base, so a second stage of isolation under the base, or an inertia base on restrained springs, is added to meet the vibration and noise criterion of the spaces around it. (16.2)
16.3 Where the set is installed inside an occupied building or on a framed floor, restrained isolators shall be furnished between the base and the pad unless the datasheet selects an inertia base.
16.4 Every isolator between the base and the pad shall be a restrained isolator, so that the set cannot leave the isolators under the seismic and wind loads applicable to the installation, and the restraints shall be included in the seismic certification where one is required.
16.5 The set shall be anchored at the manufacturer's anchor points with anchors sized for the seismic and wind loads applicable to the installation, in accordance with the seismic anchorage calculation submitted under this standard, and the anchor design shall be coordinated with Concrete PadsConcrete Equipment PadsResolves to the current adopted revision.sync/concrete-pads.
16.6 The set shall be furnished with lifting points on the base or the enclosure rated for the weight of the set with its tank empty, and the shop drawings shall show the lifting arrangement.

17 Identification and Labeling

17.1 Field-installed labels shall be provided as indicated in the datasheet and shall comply with Equipment LabelingElectrical Equipment LabelingResolves to the current adopted revision.sync/equipment-labeling.
Generator Labelingcheckbox
☑ Equipment designation matching the one-line diagram
☐ Emergency system identification
☑ Available fault current with the calculation date
☑ Arc-flash warning label
☐ NFPA 110 level and type identification
☑ Neutral bonding condition at the set
☑ Fuel type and tank capacity
☑ Remote emergency stop location
☐ Air permit identification and run-hour limit
17.2 The set shall carry the nameplate NEC 445.11 requires, giving the manufacturer, the rated frequency, the number of phases, the rated kilowatts and kilovolt-amperes, the power factor, the rated voltage and current, the rated speed, the insulation class and the temperature rise, the rating category, and whether the neutral is bonded to the frame.
17.3 The available fault current at the set terminals shall be field-marked with the date of the calculation in accordance with NEC 110.24.
17.4 Where the set serves an Article 700 emergency system, the set and its enclosure shall be marked as a component of the emergency system in accordance with NEC 700.10(A), and the sign NEC 700.7 requires at the service equipment shall identify the location of the set.
17.5 The arc-flash warning label shall carry the values established under Arc Flash StudyArc-Flash Hazard AnalysisResolves to the current adopted revision.sync/arc-flash-study for the set breaker enclosure, and shall be placed so that it is read before the enclosure is opened.
17.6 Labels shall be permanent, resistant to the environment the enclosure is selected for, and legible from the operating position without removing a cover.

18 Testing

18.1 Factory Tests

18.1.1 The manufacturer shall perform the following production tests on the set before shipment, in accordance with UL 2200 and ISO 8528-6, and shall record the results on a certified test report identified by serial number:
  • a run at the site-rated output, rated voltage, and rated frequency for not less than one hour, with the coolant, oil, and exhaust temperatures recorded
  • a single-step load acceptance at the largest step established under Emergency And Standby PowerEmergency and Standby Power SystemsResolves to the current adopted revision.sync/emergency-and-standby-power, with the transient voltage and frequency deviation and the recovery time recorded
  • verification of the steady-state voltage regulation and the frequency regulation through the load range
  • verification of every shutdown, including overspeed, low oil pressure, high coolant temperature, and overcrank, and of every alarm and pre-alarm
  • verification of the phase rotation, the voltage on each phase, and the neutral bonding condition against the order
  • an insulation resistance test of the alternator winding
  • a dielectric withstand test of the control and power wiring in accordance with UL 2200
  • a functional test of the controller, the breaker, the shunt trip, the charger, and every communications output
  • a visual and dimensional inspection, including the nameplate against the order
18.1.2 Factory test witnessing shall be as indicated in the datasheet.
Factory Test Witnessingradio
○ Witnessed by the Owner's representative
● Certified test report without witnessing
18.1.3 Where witnessing is selected, the manufacturer shall give not less than two weeks' notice of test readiness, shall submit the test procedure for review before the test, and shall not ship the set until the witness has accepted the results or has waived attendance in writing.

18.2 Field Acceptance Tests

18.2.1 Field acceptance tests shall be performed on the set in accordance with NETA ATS and Electrical Acceptance TestingElectrical Acceptance TestingResolves to the current adopted revision.sync/electrical-acceptance-testing after installation is complete and before the set is placed in service, and shall include the tests indicated in the datasheet.
Field Acceptance Testscheckbox
☑ Visual and mechanical inspection including anchorage, isolators, nameplate, clearances, and fluid levels
☑ Bolted connection resistance or torque verification
☑ Insulation resistance of the alternator winding and the feeder
☑ Neutral bonding condition verified against the derived value
☑ Phase rotation and voltage on each phase
☑ Controller settings verified against the reviewed settings record
☑ Cold start from the remote start contact with the time to rated voltage and frequency measured
☑ Load test at the load source and duration selected under this standard
☑ Step-load test at the largest step with the transient deviation and recovery time recorded
☑ Operation of every alarm, pre-alarm, and shutdown by simulation
☑ Operation of the remote annunciator and every communications point
☑ Operation of the emergency stop at the set and at the remote station
☑ Fuel level, low fuel alarm, and leak detection operation
☐ Gas supply pressure at the engine inlet at full load
☑ Battery load test and charger operation
☐ Exhaust back pressure at full load
☐ Sound pressure level at 7 m at full load
☐ Infrared scan of the breaker and power terminations under load
18.2.2 The load source for the acceptance load test shall be as indicated in the datasheet.
Acceptance Load Test Sourceradio
○ Building load
○ Building load supplemented by a load bank
○ Load bank
18.2.3 The duration of the acceptance load test shall be as indicated in the datasheet.
Acceptance Load Test Durationrange
hours
2481224
Default: Not less than 2 hours
18.2.4 Where the set serves a system classified under NFPA 110, the load test shall reach the load steps and the total duration the installation acceptance test of NFPA 110 Chapter 7 requires, and the duration selected in the datasheet shall be not less than that total.
NOTE A two-hour test at the steps NFPA 110 Chapter 7 requires is the code minimum, which is why it carries the default; a longer run is bought where the Owner wants the cooling system, the fuel system, and the aftertreatment proven at full load for a working day, and a run of a day or more is the practice of facilities whose outage plan assumes it. (18.2.5)
NOTE The building load at the time of acceptance is usually a fraction of the rated output, and a diesel engine that is never loaded above a fraction of its rating deposits unburned fuel in its exhaust; the load bank is what brings the set to the rated output it was bought for, so that the cooling, the exhaust temperature, and the aftertreatment are proven and not assumed. (18.2.6)
18.2.7 The measured time from the remote start signal to rated voltage and frequency shall be within the type time assigned under Emergency And Standby PowerEmergency and Standby Power SystemsResolves to the current adopted revision.sync/emergency-and-standby-power, and a set whose measured time exceeds it shall not be placed in service until the cause is corrected and the test repeated.
18.2.8 The field acceptance tests of the set shall be scheduled with the transfer switch field tests required under Automatic Transfer SwitchesAutomatic Transfer SwitchesResolves to the current adopted revision.sync/automatic-transfer-switches so that they roll up into the integrated system test required under Emergency And Standby PowerEmergency and Standby Power SystemsResolves to the current adopted revision.sync/emergency-and-standby-power, and the chain from source failure to load restoration is verified as one system.
18.2.9 A set that fails a field acceptance test shall not be placed in service, the Contractor shall report the failure to the Engineer of Record within one working day with the measured values, and the cost of the correction and of every repeated test shall be borne by the Contractor.

18.3 Manufacturer Startup

18.3.1 Whether the manufacturer performs a field startup shall be as indicated in the datasheet.
Manufacturer Field Startupradio
● Required, with a startup report
○ Not required
NOTE A manufacturer's startup is the condition of the warranty on nearly every packaged set, which is why it carries the default, and it is the visit at which the engine is first run under the manufacturer's eye, the controller is set to the reviewed settings record, and the warranty commences. (18.3.2)
18.3.3 Where manufacturer startup is required, the manufacturer's technician shall verify the installation against the shop drawings, shall fill and check every fluid, shall set the controller to the reviewed settings record, shall witness the cold start and the load test, and shall furnish the startup report required in the closeout submittals.

19 Installation

19.1 Placement and Clearances

19.1.1 The set shall be installed at the location and in the orientation indicated on the electrical plans, with the service sides accessible.
19.1.2 Working space at the controller, the breaker, and every terminal compartment shall comply with NEC 110.26 for the rated voltage, and the enclosure doors shall not reduce that space when open.
19.1.3 The clearance around the set shall be not less than the larger of the working space NEC 110.26 requires, the clearance to combustible construction NFPA 37 requires, and the service clearance the manufacturer publishes on the shop drawings, and the clearance to openings in the building shall satisfy NFPA 37.
19.1.4 Where the set serves a system classified as Level 1 under NFPA 110, the set shall be located with the separation from other structures and the fire separation NFPA 110 Chapter 7 requires, and where installed indoors, in a room that serves no other purpose than the set and its accessories.
19.1.5 The cooling air intake shall be located where it does not draw the radiator discharge, the exhaust, or the discharge of any other equipment, and the exhaust outlet shall be located where the prevailing wind does not carry the exhaust into a building opening.

19.2 Housekeeping Pad

19.2.1 The set shall be set on a reinforced concrete housekeeping pad constructed under Concrete PadsConcrete Equipment PadsResolves to the current adopted revision.sync/concrete-pads, extending not less than 6 in. beyond the base on every side, not less than 4 in. above the finished floor indoors or 6 in. above finished grade outdoors, and thick enough for the anchor embedment the seismic anchorage calculation requires.
19.2.2 Conduit sleeves, the fuel piping penetrations, and the grounding electrode connection shall be cast into the pad before the concrete is placed, at the locations shown on the shop drawings.

19.3 Electrical Connections

19.3.1 The feeder from the set breaker to the transfer switch shall be sized for not less than 115 percent of the rated current of the set in accordance with NEC 445.13, and shall be installed under Conductors And CablesConductors and CablesResolves to the current adopted revision.sync/conductors-and-cables and Raceways And ConduitRaceways and ConduitResolves to the current adopted revision.sync/raceways-and-conduit.
19.3.2 Power conductors shall be terminated on the lugs furnished with the set breaker, torqued to the manufacturer's published value with a calibrated torque tool, and the value shall be recorded on the field test report.
19.3.3 Where the set is installed on vibration isolators, the power and control conduits shall be connected to the set through flexible conduit or cable of a length that does not transmit vibration to the raceway system.
19.3.4 The control wiring between the set and the transfer switch, the remote annunciator, and the remote emergency stop shall be installed in raceways separate from the power conductors, and where the set serves an Article 700 system, separated in accordance with NEC 700.10.
19.3.5 The neutral bonding at the set shall be installed, or omitted, in accordance with the derived value under this standard, and the Contractor shall record the as-installed condition on the as-built one-line diagram.

19.4 Remote Emergency Stop

19.4.1 A remote emergency stop station shall be installed outside the enclosure of an outdoor set, or outside the room of an indoor set, at the location indicated on the electrical plans, in accordance with NEC 445.18, and shall shut the engine down and trip the set breaker.
19.4.2 The remote emergency stop shall be a maintained-contact station with a protective cover that prevents unintended operation, labeled with the equipment designation of the set it stops, and its circuit shall be supervised so that a broken circuit is annunciated and does not shut the engine down.
NOTE An emergency stop that opens the engine on a broken wire turns every failure of its circuit into a shutdown of a life-safety source, which is why the circuit is supervised and the stop is a positive action. (19.4.3)

19.5 Fuel and Exhaust Connections

19.5.1 Diesel fuel piping to the skid connection shall be installed under Fuel Oil SystemsFacility Fuel-Oil SystemsResolves to the current adopted revision.sync/fuel-oil-systems, the bulk tank under Fuel Dispensing And Storage TanksFuel Storage TanksResolves to the current adopted revision.sync/fuel-dispensing-and-storage-tanks, and gas piping to the gas train under Fuel Gas PipingFacility Liquefied-Petroleum and Fuel Gas PipingResolves to the current adopted revision.sync/fuel-gas-piping, and every connection at the set shall be made with the flexible connector the set furnishes.
19.5.2 The exhaust shall be installed under the exhaust article of this standard, and where the exhaust back pressure measured during the field acceptance tests exceeds the engine manufacturer's limit, the Contractor shall correct the installation and repeat the measurement at the Contractor's expense.
19.5.3 Fuel fill, vent, and gas piping shall not be routed through the cooling air discharge, over the exhaust, or where they can be struck from the service side of the set.

20 Delivery, Storage, and Handling

20.1 The set shall be delivered with the engine filled with the manufacturer's lubricant, the cooling system filled with the coolant selected under this standard or drained and tagged, the batteries shipped dry or charged as the manufacturer directs, and every shipping brace and weather seal in place.
20.2 The Contractor shall verify the delivery path, including gates, doors, ramps, floor capacity, and the crane or rigging position, against the shipping dimensions and weight on the shop drawings before the set is shipped.
20.3 The set shall be lifted at the lifting points the manufacturer identifies with rigging that clears the enclosure and the controller, and shall not be lifted by the enclosure, the radiator, or the exhaust.
20.4 Where the set stands more than 30 days on the site before startup, it shall be stored under cover or in its enclosure with the doors closed, the jacket water heater and the battery charger shall be energized from a temporary source, and the engine shall be barred over or run at the interval the manufacturer's storage instructions state.
20.5 A set damaged in transit, in storage, or in handling shall be repaired or replaced as the manufacturer directs and as the Engineer of Record accepts in writing.

21 Warranty

21.1 The manufacturer shall warrant the set, including the engine, the alternator, the controller, the enclosure, and every set-mounted accessory, against defects in materials and workmanship for the period indicated in the datasheet, measured from the date of substantial completion or the date of manufacturer startup, whichever is later.
Manufacturer's Warranty Periodrange
years
123510
NOTE The period is a term the Owner buys, from the manufacturer's base offering to an extended term on a facility whose outage plan depends on the set, so no period is the norm and the field carries no default. (21.2)
21.3 Where the manufacturer's warranty carries a limit on operating hours, the limit shall be stated in the warranty documentation, and a warranty whose hour limit is not stated shall be read as having none.
21.4 Where the contract documents state a longer warranty period than the datasheet, the longer period shall govern.
21.5 The Contractor shall warrant the installation, including every termination, the anchorage, the fuel and exhaust connections, the grounding, and the field-installed accessories, for the project warranty period.
21.6 A repair or replacement performed under this warranty shall itself be warranted for a full new term equal to the original period from the date the repair is completed, or for the remainder of the original period, whichever ends later.
21.7 The emergency field service response time committed for the warranty period shall be as indicated in the datasheet.
Emergency Field Service Response Timerange
hours
48244872
21.8 Where the set serves a system classified as Level 1 under NFPA 110, the response time shall be coordinated with the facility's continuity-of-operations plan and with the response commitment made under Automatic Transfer SwitchesAutomatic Transfer SwitchesResolves to the current adopted revision.sync/automatic-transfer-switches.
21.9 The extended service provisions furnished shall be as indicated in the datasheet.
Extended Service Provisionscheckbox
☐ Annual preventive maintenance visit for the warranty period
☐ Controller firmware updates for the warranty period
☐ Parts stocking commitment at the nearest service center
☐ Annual load bank test for the warranty period
☐ Extended warranty beyond the period stated

22 Spare Parts and Training

22.1 The Contractor shall deliver the spare parts indicated in the datasheet to the Owner before the set is accepted, and shall obtain a signed receipt for them.
Spare Parts to Be Furnishedcheckbox
☑ One set of engine filters for oil, fuel, air, and coolant
☑ One set of belts and hoses
☐ One spare starting battery matched to the set furnished
☑ One set of control fuses and indicator lamps
☐ One spare fuel level sender and one spare coolant level sensor
☑ Touch-up paint matching the enclosure finish
☑ Keys for every lock furnished
22.2 Spare parts shall be of the same manufacturer and rating as the installed items, shall be delivered in their original packaging, shall be labeled with the equipment designation of the set they serve, and the operation and maintenance data shall list the part numbers and the reorder source for each.
22.3 The Owner's operating personnel shall be trained on the set for the period indicated in the datasheet, covering normal and manual operation, the controller interface, the settings record, the alarm and shutdown response procedure, the fuel quality program, the run-hour limits of the air permit, and the routine inspection, exercise, and testing NFPA 110 Chapter 8 requires where it applies.
Operator Training Periodrange
hours
24816
22.4 Training shall be delivered by the manufacturer's authorized service representative at the site with the set in service, and a sign-in record of the topics covered and the personnel attending shall be delivered with the closeout submittals.

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"Engine Generators." SynC Standards. Licensed under CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0/). Source: https://synergyinconstruction.com/wiki/sync/generators — reference material only; not professional engineering advice and provided without warranty. Verify against governing codes and have a licensed professional review before use.