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SynC · Editorial revision

Motor Control Centers

Revision7
EditedSep 14, 2026
StatusCurrent
Contents

View changes in this revision   Revision history

Current revision. This is editorial revision 7, the current text of this standard. Read it on the standard's page.

SynC Standards Team — Specifier (Platform Standards) ✓ OfficialDiscloses employment SynC (SynC Platform Team)
Remake for template neutrality (batch 12)

1 Scope

NOTE This standard governs the low-voltage motor control center as a listed assembly: its structure, horizontal and vertical bus, wireways, unit compartments, the plug-in and frame-mounted units installed in them, the common control and communications provisions, and the field work that puts the assembly into service. (1.1)
NOTE A motor control center differs from a switchboard in that its load devices are motor controllers assembled into removable units that plug onto a shared vertical bus, so that a starter can be added, exchanged, or withdrawn for service without disturbing the bus or its neighbors. (1.2)
NOTE The assembly is one listed product. Its short-circuit rating, its seismic qualification, and its arc-flash characteristics are properties of the whole, established by the manufacturer for the configuration shipped, and a unit or a bus modification introduced outside that listing removes the assembly from the condition under which it was rated. (1.3)
NOTE The following are governed elsewhere and are outside this standard: (1.4)
  • individually enclosed combination and manual motor starters serving a single motor, under Combination Motor StartersCombination and Manual Motor StartersResolves to the current adopted revision.sync/combination-motor-starters
  • the drive performance, harmonic treatment, bypass logic, and parameter configuration of variable frequency drive units, under HVAC Variable Frequency DrivesHVAC Variable Frequency DrivesResolves to the current adopted revision.sync/hvac-variable-frequency-drives
  • the motors served, their nameplate data, and their disconnecting means at the motor
  • the short-circuit, protective device coordination, and arc-flash incident energy studies, under Arc Flash StudyArc-Flash Hazard AnalysisResolves to the current adopted revision.sync/arc-flash-study
  • the power and control conductors and their terminations, under Conductors And CablesConductors and CablesResolves to the current adopted revision.sync/conductors-and-cables
  • the raceways serving the assembly, under Raceways And ConduitRaceways and ConduitResolves to the current adopted revision.sync/raceways-and-conduit
  • the grounding electrode system and the equipment grounding conductors, under Grounding And BondingGrounding and Bonding for Electrical SystemsResolves to the current adopted revision.sync/grounding-and-bonding
  • the metering devices themselves and the monitoring system they report to, under Electrical Power MonitoringElectrical Power Monitoring and MeteringResolves to the current adopted revision.sync/electrical-power-monitoring
  • the sequences of operation, points, and network architecture of the building automation or process control system, under Building Automation SystemBuilding Automation SystemResolves to the current adopted revision.sync/building-automation-system and Process Control NetworksProcess Control NetworksResolves to the current adopted revision.sync/process-control-networks
1.5 Motor control centers shall comply with NEMA ICS 18 and shall be listed and labeled to UL 845 by a Nationally Recognized Testing Laboratory.
1.6 The number of vertical sections, the units installed in each section, and the motor, horsepower, and starter type served by each unit shall be as indicated on the motor control center schedule.
1.7 Motor control center locations shall be as indicated on the electrical plans.
1.8 The requirements of this standard apply to the assembly and to the units as installed in it; a device requirement stated in Combination Motor StartersCombination and Manual Motor StartersResolves to the current adopted revision.sync/combination-motor-starters for a stand-alone starter applies to a motor control center unit only where this standard invokes it.

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 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 845 Motor Control Centers
UL 489 Molded-Case Circuit Breakers, Molded-Case Switches, and Circuit-Breaker Enclosures
UL 508 Industrial Control Equipment
UL 60947-4-1 Low-Voltage Switchgear and Controlgear - Part 4-1: Contactors and Motor-Starters - Electromechanical Contactors and Motor-Starters
UL 61800-5-1 Adjustable Speed Electrical Power Drive Systems - Part 5-1: Safety Requirements - Electrical, Thermal and Energy
UL 50E Enclosures for Electrical Equipment, Environmental Considerations
NEMA ICS 1 Industrial Control and Systems: General Requirements
NEMA ICS 2 Industrial Control and Systems: Controllers, Contactors, and Overload Relays Rated 600 Volts
NEMA ICS 6 Industrial Control and Systems: Enclosures
NEMA ICS 18 Motor Control Centers
NEMA 250 Enclosures for Electrical Equipment (1000 Volts Maximum)
NEMA MG 1 Motors and Generators
NFPA 70 National Electrical Code (Articles 110, 240, 409, and 430)
NFPA 70E Standard for Electrical Safety in the Workplace
IEEE 1584 Guide for Performing Arc-Flash Hazard Calculations
IEEE 519 Standard for Harmonic Control in Electric Power Systems
IEEE C37.20.7 Guide for Testing Switchgear Rated Up to 52 kV for Internal Arcing Faults
ANSI/NETA ATS Standard for Acceptance Testing Specifications for Electrical Power Equipment and Systems
ASCE 7 Minimum Design Loads and Associated Criteria for Buildings and Other Structures
ICC-ES AC156 Acceptance Criteria for Seismic Certification by Shake-Table Testing of Nonstructural Components
IBC International Building Code
ANSI/ASHRAE/IES 90.1 Energy Standard for Buildings Except Low-Rise Residential Buildings

3 Submittals

3.1 Action Submittals

3.1.1 The Contractor shall submit the following for review before fabrication begins:
  • shop drawings showing front elevations, section widths, depths, and heights, shipping splits, lifting provisions, weight per shipping section, conduit entry areas, and the anchorage pattern
  • a one-line diagram of the assembly showing the incoming connection, the main device, the horizontal and vertical bus, the neutral and ground bus, and each unit by its designation
  • a unit arrangement drawing for each vertical section showing the compartment size and contents of every unit, including spare and space compartments
  • a bill of material for each unit listing the disconnect, the controller, the overload relay, the control power transformer, the pilot devices, the auxiliary contacts, and the network interface
  • schematic and wiring diagrams for each unit type and for the common control and communications wiring
  • the assembly short-circuit current rating and the bus bracing rating, with the basis on which each was established
  • the tested series-rated combinations, where series ratings are the rating basis, identifying the upstream device on which each rating depends
  • the seismic qualification certificate for the assembly as configured, where seismic qualification is required
  • product data for every device installed in a unit, and for the metering and network components
  • the nameplate schedule listing the text to appear on the assembly, section, and unit nameplates
Action Submittal Packagecheckbox
☑ Shop drawings
☑ Assembly one-line diagram
☑ Unit arrangement drawings
☑ Unit bills of material
☑ Schematic and wiring diagrams
☑ Short-circuit and bus bracing rating basis
☐ Series-rated combination listing
☐ Seismic qualification certificate
☑ Device product data
☑ Nameplate schedule
3.1.2 Fabrication shall not begin until the action submittals have been reviewed and returned.

3.2 Informational Submittals

3.2.1 The Contractor shall submit the following with or before the action submittals:
  • the manufacturer's qualification statement and the UL 845 file reference under which the assembly will be listed
  • the qualifications of the firm and the technicians who will perform field acceptance testing
  • the factory test procedure, where witnessed factory testing is indicated
  • the harmonic analysis required by HVAC Variable Frequency DrivesHVAC Variable Frequency DrivesResolves to the current adopted revision.sync/hvac-variable-frequency-drives, where drive units are installed in the assembly
  • the manufacturer's published derating factors applied for ambient temperature and altitude, where either exceeds the usual service conditions of NEMA ICS 1
Informational Submittal Packagecheckbox
☐ Manufacturer qualification statement
☐ Field testing firm and technician qualifications
☐ Factory test procedure
☐ Harmonic analysis
☐ Ambient and altitude derating factors

3.3 Closeout Submittals

3.3.1 The Contractor shall submit the following before the assembly is accepted:
  • operation and maintenance data covering the structure, the bus, each unit type, and each device installed in a unit
  • record drawings reflecting every field change to the unit arrangement, the wiring, and the network addressing
  • the certified factory test report and the field acceptance test report
  • the manufacturer's start-up report, where manufacturer start-up is indicated
  • the final settings of every adjustable device, including overload relay dial and class settings, trip unit settings, soft starter parameters, and the drive parameter files
  • the network address list and the point list for every networked device
  • the arc-flash incident energy labels installed, with the study revision they were taken from
  • the warranty certificate identifying the assembly serial number and the warranty commencement date
  • a signed receipt from the Owner for the spare units and spare parts delivered
Closeout Submittal Packagecheckbox
☑ Operation and maintenance data
☑ Record drawings
☑ Factory and field test reports
☐ Manufacturer start-up report
☑ Final device settings and parameter files
☐ Network address and point list
☐ Arc-flash label record
☑ Warranty certificate
☑ Spare parts receipt

4 Quality Assurance

4.1 Manufacturer Qualifications

4.1.1 The assembly shall be produced by a manufacturer who has held a UL 845 listing for motor control centers of the type furnished for not less than the period indicated in the datasheet.
Minimum Manufacturer Listing Historyrange
years
351020
4.1.2 The manufacturer shall maintain a factory-trained field service organization able to reach the site, and shall state the location of the nearest such office in the qualification statement.
4.1.3 The manufacturer shall state in the qualification statement the period, measured from the date of manufacture, for which replacement plug-in units and bus components for the assembly platform will remain available.

4.2 Source Limitations

4.2.1 The structure, horizontal bus, vertical bus, unit compartments, unit chassis, and common control provisions shall be furnished by one manufacturer under one UL 845 listing.
4.2.2 A unit assembled or modified by a party other than the manufacturer shall be installed in the assembly only where the manufacturer confirms in writing that the unit is covered by the assembly listing and that the assembly short-circuit current rating is unchanged.
NOTE A unit in the listing whose contents come from another maker, such as a drive or a meter, remains covered by the assembly listing only where the manufacturer installed it in a unit of its own construction and evaluated it as part of the assembly. (4.2.3)

4.3 Field Testing Firm

4.3.1 Field acceptance testing shall be performed by the firm indicated in the datasheet.
Field Acceptance Testing Firmradio
○ Independent testing firm accredited to ANSI/NETA ATS
○ Manufacturer's field service organization
○ Installing contractor's own technicians
4.3.2 The technicians who perform field acceptance testing shall hold a current certification for low-voltage equipment testing from NETA or from the manufacturer of the equipment tested, and shall have tested motor control centers of the type furnished.
NOTE An independent firm has no stake in whether the assembly passes and reports against a published acceptance standard; the manufacturer's organization knows the product best and is already on site for start-up; the installing contractor's own technicians cost least and are available on the installer's schedule. Which of these the Owner wants depends on how the results will be used, and on whether a report from the party who built or installed the equipment would satisfy the Owner's insurer and the Authority Having Jurisdiction. (4.3.3)

5 Environmental and Service Conditions

5.1 Ambient Temperature

5.1.1 The assembly shall carry its nameplate continuous current ratings at the design ambient temperature of the room indicated in the datasheet.
Indoor Design Ambient Temperaturerange
°C
40455055
NOTE The usual service conditions of NEMA ICS 1 and UL 845 establish the ratings at a 40 °C ambient, so a 40 °C design ambient is the condition at which the nameplate applies without correction; a higher value buys margin for a room whose ventilation cannot hold that ambient at design load, at the cost of a larger bus or a larger unit for the same connected load. (5.1.2)
5.1.3 Where the assembly is installed outdoors and Site Ambient Temperature MaximumSite Ambient Temperature MaximumParameterEach project supplies its own value.site-ambient-temperature-maximum exceeds 40 °C, the manufacturer shall derate the bus and the units in accordance with its published factors and shall state the derated ratings in the action submittals.
5.1.4 Where the assembly is installed outdoors, the enclosure space heaters shall be sized to hold the interior above the dew point at Site Ambient Temperature MinimumSite Ambient Temperature MinimumParameterEach project supplies its own value.site-ambient-temperature-minimum.

5.2 Altitude

5.2.1 The assembly shall be derated for AltitudeAltitudeParameterEach project supplies its own value.altitude in accordance with the manufacturer's published correction factors where the altitude exceeds the 2000 m usual service condition of NEMA ICS 1.
NOTE Air thins with altitude, which reduces both the convective cooling that sets the continuous current rating and the dielectric strength of the clearances inside the assembly, so a unit rated at sea level carries less current and less insulation margin at elevation than its nameplate states. (5.2.2)
5.2.3 Ambient temperature derating and altitude derating shall be applied cumulatively where both conditions apply.

5.3 Humidity

5.3.1 The assembly shall be rated for operation at a relative humidity up to 95%, non-condensing.
5.3.2 Where the installed location is unconditioned, whether indoors or outdoors, thermostatically controlled space heaters shall be furnished in each vertical section and shall be supplied from a circuit that stays energized while the assembly main device is open.

5.4 Seismic Qualification

5.4.1 The seismic qualification of the assembly shall be as indicated in the datasheet.
Seismic Qualificationselect
Not required
Shake-table qualification per ICC-ES AC156 with component importance factor 1.0
Shake-table qualification per ICC-ES AC156 with component importance factor 1.5
Qualification by analysis per ASCE 7 Chapter 13
Derived — Seismic Design CategorySeismic Design CategoryParameterEach project supplies its own value.seismic-design-category and the component importance factor ASCE 7 Chapter 13 assigns to the assembly (by default)
5.4.2 Where seismic qualification is required, it shall be performed in accordance with the seismic provisions of Adopted Building CodeAdopted Building CodeParameterEach project supplies its own value.adopted-building-code and ASCE 7 Chapter 13.
NOTE Whether the assembly must be qualified follows from the seismic design category, and whether it must remain operable after the design earthquake, rather than merely stay anchored, follows from the component importance factor; neither is decided within this standard. (5.4.3)
5.4.4 Seismic qualification shall cover the complete assembly in the configuration shipped, including every installed unit and the heaviest unit arrangement in any section.
5.4.5 A certificate covering a single section, an empty structure, or a component tested apart from the assembly shall not be accepted as qualification of the assembly.
5.4.6 A field change to the unit arrangement that departs from the qualified configuration shall be re-evaluated by the manufacturer against the qualification before the assembly is energized.

6 Electrical Ratings

6.1 Service Configuration

6.1.1 Whether the assembly is service entrance equipment shall be as indicated in the datasheet.
Service Configurationradio
○ Service entrance equipment
○ Downstream distribution equipment
Per drawings — the one-line diagram (deferred by default)
6.1.2 Where the assembly is service entrance equipment, it shall be listed as suitable for use as service equipment and shall comply with NFPA 70 Article 230, including the service disconnect, the available fault current marking, and the grounding electrode conductor termination.

6.2 System Voltage and Frequency

6.2.1 The system voltage and configuration shall be as indicated in the datasheet.
System Voltageselect
208Y/120 V 3Φ 4-wire
240 V 3Φ 3-wire delta
240/120 V 3Φ 4-wire high-leg delta
480Y/277 V 3Φ 4-wire
480 V 3Φ 3-wire delta
600Y/347 V 3Φ 4-wire
600 V 3Φ 3-wire delta
Per drawings — the one-line diagram (deferred by default)
6.2.2 The system frequency shall be as indicated in the datasheet.
System Frequencyradio
● 60 Hz
○ 50 Hz

6.3 Main Device

6.3.1 The incoming main device shall be as indicated in the datasheet.
Main Device Typeselect
Main lugs only
Main circuit breaker
Main fusible switch
Main insulated-case circuit breaker
Per drawings — the one-line diagram (deferred by default)
6.3.2 The main device frame and trip rating shall be as indicated on the one-line diagram.
6.3.3 The trip unit of a main circuit breaker shall be as indicated in the datasheet.
Main Circuit 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
Per drawings — the one-line diagram (deferred by default)
6.3.4 Ground-fault protection of equipment on the main device shall be as indicated in the datasheet.
Ground-Fault Protection of Equipment on the Main Deviceradio
○ Not provided
○ Provided
Derived — NFPA 70 230.95 and 215.10 applied to the system voltage, the main device rating, and whether the assembly is service entrance equipment (by default)
NOTE Whether the main device must carry ground-fault protection of equipment is fixed by code from the system grounding, the voltage to ground, and the device rating, so the field records the consequence of those inputs rather than a preference; a project may add ground-fault protection where code does not require it. (6.3.5)

6.4 Bus Continuous Current

6.4.1 The horizontal bus continuous current rating shall be as indicated in the datasheet.
Horizontal Bus Continuous Currentrange
A
6008001000120016002000250030003200
Per drawings — the one-line diagram (deferred by default)
6.4.2 The vertical bus continuous current rating shall be as indicated in the datasheet.
Vertical Bus Continuous Currentrange
A
30060080012001600
Per drawings — the motor control center schedule (deferred by default)
6.4.3 The vertical bus in each section shall carry the sum of the full-load currents of the units installed in that section, and the manufacturer shall confirm the loading of each section on the unit arrangement drawings.
NOTE A section populated with several large starters, soft starters, or drive units can exceed the lowest vertical bus rating before it runs out of compartment space, which is why the vertical bus is confirmed per section against the units actually installed rather than assumed from the horizontal bus. (6.4.4)

6.5 Short-Circuit Ratings

6.5.1 The assembly short-circuit current rating marked on the nameplate shall equal or exceed the available fault current at the line terminals, and shall be as indicated in the datasheet.
Assembly Short-Circuit Current Ratingrange
kA
1014182225303542506585100
Per drawings — the one-line diagram (deferred by default)
6.5.2 The bus short-circuit bracing shall be as indicated in the datasheet.
Bus Short-Circuit Bracingrange
kA
1014182225303542506585100
Derived — the assembly short-circuit current rating; the bus is braced to not less than the rating marked on the assembly (by default)
NOTE The marked assembly rating is the lowest of the bus bracing, the interrupting rating of each unit disconnect, and the rating of each combination controller as tested under UL 845, so the bus bracing is a floor beneath the assembly rating rather than a separate choice. (6.5.3)
6.5.4 The basis on which the assembly rating is established shall be as indicated in the datasheet.
Fault Current Rating Basisradio
● Fully rated
○ Series rated
NOTE A fully rated assembly carries a rating on every unit that stands on its own; a series-rated assembly reaches its marked rating through tested combinations in which a downstream device is rated only when the specific upstream device it was tested with remains in place, so a later change to the main device or to an upstream breaker can silently void the rating. Series rating lowers the cost of the units where the available fault current is high, and is used where the upstream device is under the same Owner's control and is not expected to change. (6.5.5)
6.5.6 Where series rating is the basis, every series-rated combination shall be marked on the assembly in accordance with NFPA 70 110.22, and the upstream device on which each rating depends shall be identified in the action submittals.

6.6 Neutral and Ground Bus

6.6.1 The neutral bus shall be as indicated in the datasheet.
Neutral Busselect
No neutral bus
Neutral bus rated 100% of the horizontal bus
Neutral bus rated 200% of the horizontal bus
Derived — the system voltage configuration (three-wire or four-wire) and the share of nonlinear load served from the assembly (by default)
NOTE A three-wire system has no neutral to carry, a four-wire system carries one rated with the phase bus, and a four-wire system whose load is predominantly nonlinear carries the triplen harmonic currents that add in the neutral rather than cancel, which is the condition under which the neutral is rated above the phase bus. (6.6.2)
6.6.3 Where a neutral bus is furnished, it shall be insulated from the structure, and where the assembly is service entrance equipment the main bonding jumper shall be furnished by the manufacturer.
6.6.4 The ground bus shall be as indicated in the datasheet.
Ground Busradio
● Full-length ground bus
○ No ground bus
NOTE An assembly added to an existing lineup whose ground bus continues through the joined sections is the case in which a ground bus of its own is omitted; every free-standing assembly carries one. (6.6.5)
6.6.6 Where a ground bus is furnished, it shall be copper, shall extend the full length of the assembly, and shall be accessible from the front of each section without removing a bus barrier.
6.6.7 Each plug-in unit shall make ground continuity to the ground bus through a dedicated ground stab that engages before the line stabs on insertion and releases after them on withdrawal.
6.6.8 Grounding and bonding of the assembly shall comply with Grounding And BondingGrounding and Bonding for Electrical SystemsResolves to the current adopted revision.sync/grounding-and-bonding.

7 Enclosure and Structure

7.1 Enclosure Type

7.1.1 The enclosure type shall be as indicated in the datasheet.
Enclosure Type per NEMA 250select
Type 1
Type 1 gasketed
Type 12
Type 3R
Type 4
Type 4X
NOTE A dry, conditioned electrical room is the installed location on most projects, and a Type 1 enclosure is the construction rated for it; the gasketed and Type 12 constructions keep out the dust of an unconditioned mechanical or process space, Type 3R is the outdoor construction, and Type 4 and Type 4X are the washdown and corrosive-exposure constructions. (7.1.2)
7.1.3 Where the assembly is installed outdoors, the enclosure shall be Type 3R at minimum, with rain hoods over ventilation openings and a drip shield over each door.
7.1.4 Where the assembly is installed outdoors, the outdoor housing arrangement shall be as indicated in the datasheet.
Outdoor Housing Arrangementradio
○ Non-walk-in
○ Walk-in aisle
NOTE A walk-in housing puts the working space inside a weatherproof room so that a unit can be serviced in any weather, at the cost of a larger and heavier structure; a non-walk-in housing is the smaller and lighter structure, and its working space is the outdoor pad in front of it. (7.1.5)
7.1.6 Where a walk-in housing is furnished, the aisle shall provide the working space required by NFPA 70 110.26 in front of every unit door, and the housing shall have lighting, a convenience receptacle, and a door openable from inside without a key.

7.2 Enclosure Material and Finish

7.2.1 The enclosure material shall be as indicated in the datasheet.
Enclosure Materialselect
Painted steel
Type 304 stainless steel
Type 316 stainless steel
7.2.2 Where a Type 4X enclosure is indicated, the enclosure material shall be a stainless steel or another material listed for the Type 4X rating.
7.2.3 Structural members shall be steel of not less than 12 gauge, and doors and covers shall be steel of not less than 14 gauge, formed and reinforced so that a door does not deflect when opened with its devices installed.
7.2.4 The finish system applied to a painted steel enclosure shall be as indicated in the datasheet.
Painted Steel Finish Systemselect
Polyester powder coat over a phosphate pretreatment
Epoxy powder coat over a phosphate pretreatment
Two-coat epoxy primer and polyurethane topcoat
Manufacturer's standard (by default)
7.2.5 The manufacturer shall state the finish system and its dry film thickness in the product data.
NOTE A polyester powder coat is the finish the assemblies are built with and holds up indoors and in ordinary outdoor exposure; an epoxy powder coat resists chemical splash better and chalks faster in sunlight; a two-coat liquid system is applied where a chemical or marine exposure has already been identified and the enclosure is not being made of stainless steel. (7.2.6)
7.2.7 The finish color shall be as indicated in the datasheet.
Finish Colorselect
ANSI 61 light gray
ANSI 49 medium gray
ANSI 70 sky gray
Custom color matched to a sample furnished by the Owner

7.3 Section Arrangement

7.3.1 The section accessibility shall be as indicated in the datasheet.
Section Accessibilityselect
Front-accessible, single-sided
Front-accessible, back-to-back sections
Front- and rear-accessible
NOTE A single-sided assembly stands against a wall and needs working space on one side only; a back-to-back assembly puts two rows of units on a shared horizontal bus in the depth of one, which halves the floor length for the same unit count but needs working space on both faces; a rear-accessible assembly provides rear cable access for large incoming conductors at the cost of a rear working space that a single-sided assembly does not need. (7.3.2)
7.3.3 Section depth and height shall be the manufacturer's standard for the largest unit installed, and shall be shown on the shop drawings.
7.3.4 Sections shall be bolted together to form a rigid continuous assembly, with the horizontal bus spliced at every shipping split by a bolted splice plate furnished by the manufacturer.

7.4 Wireways and Conduit Entry

7.4.1 Conduit entry to the assembly shall be as indicated in the datasheet.
Conduit Entryradio
○ Top entry
○ Bottom entry
○ Top and bottom entry
Per drawings — the electrical plans (deferred by default)
7.4.2 Each vertical section shall have a vertical wireway running the full height of the section, adjacent to the unit compartments, separated from the bus and from the unit compartments by a barrier, and closed by a hinged or removable cover.
7.4.3 The vertical wireway shall be sized so that the load and control conductors of every unit in the section fit within the fill limits of NFPA 70 Article 312.
7.4.4 A horizontal wireway shall be furnished at the top and at the bottom of the assembly, continuous through the sections, and isolated from the horizontal bus by a barrier.
7.4.5 Conduit shall enter only through the wireway areas designated on the shop drawings; the bus compartments, the unit compartments, and the barriers between them shall not be penetrated.

7.5 Barriers and Unit Doors

7.5.1 The horizontal bus, the vertical bus, each unit compartment, and each wireway shall be separated from one another by grounded metal barriers.
7.5.2 Each unit compartment shall have its own hinged door, interlocked to the unit disconnect so that the door cannot be opened with the disconnect closed and the disconnect cannot be closed with the door open, with a tool-operable defeat for authorized testing.
7.5.3 The unit disconnect operating handle shall be operable from outside the closed door and shall accept not fewer than three padlocks in the open position.
7.5.4 The disconnect of a unit shall be capable of being padlocked in the open position with the unit in the connected, the test, and the withdrawn positions.

8 Bus

8.1 Horizontal Bus Material

8.1.1 The horizontal bus material shall be as indicated in the datasheet.
Horizontal Bus Materialradio
○ Copper
○ Aluminum
NOTE Copper bus carries more current per unit cross-section, needs no special joint preparation, and costs more; aluminum bus is lighter and less expensive for the same rating, and its joints depend on plating and on the joint hardware to hold their resistance through thermal cycling, which is why aluminum is used where the cost difference on a large bus matters and the joint construction is tested as part of the listing. (8.1.2)
8.1.3 Where aluminum horizontal bus is selected, it shall be an alloy and temper the manufacturer has tested under the assembly listing, and every bolted joint shall be plated through the contact area.
8.1.4 The vertical bus shall be copper.
NOTE The vertical bus carries the stab contacts of every unit, and each insertion and withdrawal scrapes the plating across the contact surface; copper holds a plated contact surface through that wear, which is why vertical bus is copper regardless of the horizontal bus material. (8.1.5)

8.2 Bus Plating

8.2.1 The bus plating shall be as indicated in the datasheet.
Bus Platingradio
○ Tin plating
○ Silver plating
Manufacturer's standard (by default)
8.2.2 The manufacturer shall state the plating in the product data.
NOTE Silver plating has the lower contact resistance and is the historic choice for stab contacts; tin plating resists tarnishing in atmospheres containing sulfur compounds, which blacken silver and raise its contact resistance, and is the plating applied to most assemblies as built. Where the installed environment carries hydrogen sulfide, as in a wastewater facility, tin is the plating that holds its contact resistance. (8.2.3)
8.2.4 Plating shall be continuous over every bolted joint contact surface and over the full length of the vertical bus stab contact area.

8.3 Bus Joints and Bracing

8.3.1 Bus joints shall be bolted with hardware that maintains contact pressure through thermal cycling, and the joint hardware and torque shall be those established under the assembly listing.
8.3.2 The bus shall be braced to withstand the bus short-circuit bracing indicated in the datasheet without damage, and the bracing shall be maintained through every shipping split.

8.4 Bus Protection Provisions

8.4.1 The bus protection provisions furnished shall be as indicated in the datasheet.
Bus Protection Provisionscheckbox
☐ Insulated horizontal bus
☐ Insulated and isolated vertical bus
☐ Automatic shutters over unused vertical bus stab openings
☐ Manual blanking covers over unused vertical bus stab openings
☐ Insulated bus splice covers at shipping splits
NOTE An insulated and isolated vertical bus exposes bare bus only at the stab opening a unit occupies; automatic shutters close the opening the moment a unit is withdrawn, where manual blanking covers depend on the person who withdrew the unit to install them. Each provision reduces the bare bus a worker can reach with a unit out of its compartment, and each adds cost to every section. (8.4.2)
8.4.3 Every unused vertical bus stab opening shall be covered by a shutter or a blanking cover when the assembly is delivered.

8.5 Bus Extension Provisions

8.5.1 The provisions for future extension of the assembly shall be as indicated in the datasheet.
Bus Extension Provisionsselect
No extension provisions
Extension provisions at one end
Extension provisions at both ends
NOTE Extension provisions consist of a removable end closure, horizontal bus ends drilled for a splice, and ground and neutral bus ends drilled to match, so that a section can be added without drilling live bus. (8.5.2)

9 Wiring Class and Type

9.1 Wiring Class

9.1.1 The NEMA ICS 18 wiring class of the assembly shall be as indicated in the datasheet.
Wiring Class per NEMA ICS 18radio
● Class I
○ Class II
NOTE A Class I assembly is furnished with no control interconnection between units; each unit is complete in itself and the interlocking and sequencing wiring between units is field work. A Class II assembly is furnished with the inter-unit control wiring installed at the factory from an elementary diagram furnished with the order, so that sequencing, interlocks, and a control-logic interface arrive wired and tested. (9.1.2)
NOTE Class II construction moves the inter-unit wiring and its checkout from the site to the factory, which shortens the site work and produces a tested system when the interlocking between units is extensive, at the cost of an elementary diagram that must be complete before the order is placed and a longer lead time when it changes. (9.1.3)
9.1.4 Where Class II wiring is selected, the elementary diagram from which the manufacturer wires the assembly shall be as indicated on the motor control center control diagrams.

9.2 Wiring Type

9.2.1 The NEMA ICS 18 wiring type shall be as indicated in the datasheet.
Wiring Type per NEMA ICS 18select
Type A
Type B-D
Type B-T
Type C
NOTE Type A furnishes no terminal blocks, so field control and load conductors land directly on the device terminals within the unit; Type B-D furnishes unit terminal blocks for control conductors with load conductors landing on the disconnect or the overload relay inside the unit; Type B-T furnishes unit control terminal blocks and, for the smaller units, load terminal blocks mounted in the vertical wireway so that a load conductor can be landed without opening the unit; Type C extends the control conductors of every unit to master terminal blocks at the top or bottom of each section, with the option of load terminal blocks there as well. (9.2.2)
NOTE Each step from Type A toward Type C moves more of the field termination out of the unit and toward a point the installer can reach without opening a door, at the cost of terminal blocks, wire, and section space; a Type C assembly is also the one in which a unit can be exchanged without disturbing any field-landed control conductor. (9.2.3)
9.2.4 Where a wiring type with terminal blocks is selected, every terminal block shall be permanently marked with the conductor designations shown on the schematic diagrams.
9.2.5 Control wiring within a unit and between units shall be stranded copper, not smaller than 16 AWG, and the source of every control circuit shall be identified at the unit.

10 Arc-Flash Mitigation and Maintenance Safety

10.1 Arc Energy Reduction

10.1.1 Where a circuit breaker in the assembly is rated or can be adjusted to 1200 A or more, arc energy reduction shall be provided in accordance with NFPA 70 240.87 by the method indicated in the datasheet.
Arc Energy Reduction Methodselect
Not applicable, no device rated 1200 A or more
Energy-reducing maintenance switching with local status indicator
Zone-selective interlocking
Differential relaying
Energy-reducing active arc-flash mitigation system
Instantaneous trip setting below the available arcing current
Derived — NFPA 70 240.87 applied to the rating of the main device and of each feeder device shown on the one-line diagram (by default)
NOTE Whether arc energy reduction is required is fixed by the device rating, so the field carries the consequence of the one-line diagram; only the method is a project selection where the threshold is met. (10.1.2)
NOTE An energy-reducing maintenance switch lowers the instantaneous pickup for the duration of the work and depends on a worker turning it on; zone-selective interlocking and differential relaying act without a worker's intervention but need the downstream devices or the current transformers to be part of the scheme; an active mitigation system detects the arc itself by light and current and clears it faster than any trip unit, at the highest cost. (10.1.3)
10.1.4 Where energy-reducing maintenance switching is selected, the switch shall be lockable in the maintenance position and its status shall be indicated at the switch and, where a network is furnished, over the network.

10.2 Arc-Resistant Construction

10.2.1 Arc-resistant construction shall be as indicated in the datasheet.
Arc-Resistant Constructionselect
Not required
Type 1 accessibility per IEEE C37.20.7
Type 2 accessibility per IEEE C37.20.7
Type 2B accessibility per IEEE C37.20.7
NOTE Arc-resistant construction directs the products of an internal arcing fault away from the front of the assembly, and Type 2 extends that protection to the sides and rear; Type 2B additionally keeps the protection with a unit door open for the low-voltage control compartment. It protects a worker standing at the assembly during an arcing fault with the doors closed and latched, and it adds a plenum, reinforced doors, and pressure-relief flaps that raise the height and the cost of every section. (10.2.2)
10.2.3 Where arc-resistant construction is selected, the assembly shall have been tested to IEEE C37.20.7 in the configuration furnished, and the exhaust plenum and its discharge location shall be shown on the shop drawings.
NOTE Arc-resistant construction does not lower the incident energy at a unit whose door is open, and does not substitute for the arc energy reduction required by NFPA 70 240.87. (10.2.4)

10.3 Maintenance Safety Provisions

10.3.1 The maintenance safety provisions furnished shall be as indicated in the datasheet.
Maintenance Safety Provisionscheckbox
☐ Infrared inspection windows at bus joints and main terminations
☐ Voltage presence indicator at each unit
☐ Absence-of-voltage tester at the main device
☐ Remote operator for the main device
☐ Unit test position with control power available
NOTE Each provision lets a task be performed with less exposure than the alternative: an infrared window lets a bus joint be scanned under load with the cover on, a voltage indicator confirms the state of a unit before its door is opened, an absence-of-voltage tester verifies a de-energized state without a handheld meter, a remote operator lets the main be closed from outside the arc-flash boundary, and a test position lets a unit's control circuit be checked with its power stabs disengaged. (10.3.2)
10.3.3 Arc-flash incident energy labels shall be applied to each section in accordance with NFPA 70 110.16 and NFPA 70E, with the values taken from the study performed under Arc Flash StudyArc-Flash Hazard AnalysisResolves to the current adopted revision.sync/arc-flash-study.

11 Plug-In Units

11.1 Unit Construction

11.1.1 Units shall be plug-in units that engage the vertical bus through self-aligning, spring-loaded stab connectors, except where the unit exceeds the largest plug-in frame the manufacturer furnishes.
11.1.2 A unit larger than the largest plug-in frame shall be a frame-mounted unit bolted to the structure and connected to the bus by bolted connections made by the manufacturer.
11.1.3 Units shall be built in the standard NEMA ICS 18 compartment increments so that a unit can be moved to any compartment of the same size in the assembly.
11.1.4 Each plug-in unit shall have a positive latch that holds it in the connected position, and a withdrawal mechanism that disengages the stabs without pulling on the unit door or its devices.
11.1.5 Each plug-in unit shall be capable of being withdrawn to a position in which its power stabs are disengaged and the unit remains supported by the structure.
11.1.6 Each unit compartment shall carry a nameplate on the door and a matching designation inside the compartment, so that a withdrawn unit and its compartment can be matched.

11.2 Combination Starter Units

11.2.1 Combination starter units shall comply with NEMA ICS 2 and UL 845, and each shall consist of a unit disconnect, a contactor, an overload relay, a control power source, and the pilot devices, assembled and wired by the manufacturer in one unit.
11.2.2 The unit disconnect of a combination starter unit shall be as indicated in the datasheet.
Combination Starter Unit Disconnect Typeselect
Instantaneous-trip circuit breaker
Thermal-magnetic circuit breaker
Fusible disconnect switch
NOTE An instantaneous-trip circuit breaker carries no thermal element and is adjusted above the motor inrush so that it clears only faults, leaving running overload protection to the overload relay; it is listed for use only as part of a tested combination and offers the closest coordination with a motor's starting current. A thermal-magnetic breaker adds its own thermal element as a second layer of overload protection, which lets it stand alone but which can trip on a long start unless it is sized above the inrush. A fusible switch provides the highest interrupting rating in the smallest unit and clears a high-magnitude fault fastest, at the cost of a fuse replacement after every fault and a single-phasing exposure that the overload relay must cover. (11.2.3)
11.2.4 Where an instantaneous-trip circuit breaker is selected, its trip setting shall be set within the range NFPA 70 430.52 permits for the motor served and shall be recorded in the closeout submittals.
11.2.5 Where a fusible disconnect switch is selected, the fuse class and the rejection feature shall be as indicated on the motor control center schedule.
11.2.6 The coordination type of each combination starter unit shall be as indicated in the datasheet.
Combination Controller Coordination Typeradio
○ Type 1
○ Type 2
NOTE Under UL 60947-4-1, a Type 1 coordinated combination survives a short circuit without hazard to persons or to the installation but may need its contactor or overload relay replaced before it is returned to service; a Type 2 coordinated combination is tested so that the contactor and overload relay remain serviceable after the fault, with light contact welding that can be separated permitted. Type 2 coordination is reached by pairing a specific disconnect with a specific contactor and overload relay, and is used where the time to return a motor to service after a fault matters more than the cost of the tested pairing. (11.2.7)
11.2.8 The coordination type shall be established by a tested combination published by the manufacturer, and the tested pairing shall be identified in the unit bill of material.

11.3 Reduced-Voltage Starter Units

11.3.1 The units that start at reduced voltage shall be as indicated on the motor control center schedule.
11.3.2 The reduced-voltage starting method for those units shall be as indicated in the datasheet.
Reduced-Voltage Starting Methodselect
Solid-state soft starter
Autotransformer, closed transition
Wye-delta, closed transition
Wye-delta, open transition
Part-winding
Primary resistor
NOTE A solid-state soft starter ramps the voltage continuously and can also stop the motor gently, and its starting current is adjustable after installation; an autotransformer starter delivers the highest starting torque per ampere of line current of the electromechanical methods; a wye-delta starter needs a motor wound with both ends of each phase brought out; part-winding needs a motor wound for it; and a primary resistor starter dissipates the starting energy as heat. The electromechanical methods start at a fixed reduction set by their taps or their winding, and an open-transition method draws a second inrush at the transition that a closed-transition method avoids. (11.3.3)
11.3.4 Where a solid-state soft starter is selected, the bypass arrangement shall be as indicated in the datasheet.
Soft Starter Bypass Arrangementradio
○ No bypass contactor
○ Integral bypass contactor
○ Separate full-rated bypass contactor
NOTE A soft starter without a bypass carries the running current through its power semiconductors for the whole run and dissipates their conduction loss continuously, so the unit is sized and ventilated for that heat; an integral bypass contactor carries the running current once the motor is at speed, removes the running loss, and lets the unit run cooler, but it is rated to close and carry rather than to start; a separate full-rated bypass contactor can start the motor across the line with the soft starter out of service, at the cost of a contactor of the full starter size. The running loss is what makes a bypass worth its cost on a large motor that runs continuously, and what makes it unnecessary on a small motor that runs briefly. (11.3.5)
11.3.6 Reduced-voltage starter units shall include a running overload relay that protects the motor through the start as well as during the run.

11.4 Contactors and Overload Relays

11.4.1 The contactor rating basis shall be as indicated in the datasheet.
Contactor Rating Basisradio
● NEMA-rated per NEMA ICS 2
○ IEC-rated per UL 60947-4-1
NOTE A NEMA-rated contactor is rated by size for any motor of that horsepower on any duty, with a contact mass sized accordingly; an IEC-rated contactor is rated by utilization category for the specific duty applied, so a smaller and less expensive contactor can serve the same motor where the duty is known and stays within the category, and a larger one is needed where it does not. The difference shows in a high-cycle or plugging duty, where a contactor sized to its rated category has less margin than the NEMA size, and in the space a unit needs. (11.4.2)
11.4.3 Contactors shall be rated for the horsepower and voltage of the motor served, with the size or utilization category stated in the unit bill of material.
11.4.4 The overload relay type shall be as indicated in the datasheet.
Overload Relay Typeselect
Electronic
Bimetallic thermal
Eutectic melting-alloy thermal
NOTE An electronic overload relay measures the motor current directly and adds phase loss, phase unbalance, and ground-fault sensing, a selectable trip class, and a communications interface where one is furnished, which is why it has become the relay the assemblies are built with; a bimetallic relay trips on the heat of a heater element and is adjustable within a range; a melting-alloy relay trips when its solder pot melts and is set by the heater installed, with no adjustment and no additional protection. (11.4.5)
11.4.6 The overload relay trip class shall be as indicated in the datasheet.
Overload Relay Trip Classrange
510152030
11.4.7 Where a different trip class is indicated for a unit on the motor control center schedule, that class shall govern for that unit.
NOTE The trip class is the number of seconds within which the relay trips at 600% of its setting; Class 20 is the class NEMA ICS 2 establishes for general-purpose motors, Class 10 protects a motor that reaches temperature quickly, and Class 30 rides through the long start of a high-inertia load that a lower class would trip on. (11.4.8)
11.4.9 Each overload relay shall be selected and set for the full-load current and the service factor of the motor served, in accordance with NFPA 70 430.32.
11.4.10 Each overload relay shall have a manual reset accessible from the front of the closed unit door, and the reset provisions for remote or automatic reset shall be furnished only where indicated on the motor control center schedule.

11.5 Control Power

11.5.1 The control voltage for starter units shall be as indicated in the datasheet.
Control Voltageselect
120 V AC from a control power transformer in each unit
120 V AC from a common control power transformer with a control power bus
24 V DC from a common control power supply with a control power bus
24 V AC from a control power transformer in each unit
Line voltage without a transformer
NOTE A transformer in each unit keeps every unit self-contained and lets it be tested and exchanged without a common control source; a common control power source removes a transformer from every unit and reduces heat and unit size, at the cost of a single source whose loss stops every motor it controls. A 24 V DC control source is the arrangement used where the unit control circuits interface directly with a programmable controller's field wiring, and a line-voltage control circuit is the arrangement a small assembly uses where no pilot device is touched by an operator. (11.5.2)
11.5.3 Where a control power transformer is furnished in a unit, it shall be sized for the connected control load, including the contactor coil inrush, with primary and secondary overcurrent protection in accordance with NFPA 70 Article 430 Part VI.
11.5.4 Where a common control power source is furnished, its loss shall be alarmed, and its distribution to the units shall be through a control power bus furnished by the manufacturer.

11.6 Pilot Devices

11.6.1 Each starter unit shall be furnished with the door-mounted devices indicated in the datasheet.
Starter Unit Door Devicescheckbox
☑ Hand-off-automatic selector switch
☐ Start and stop pushbuttons
☑ Run pilot light
☐ Stopped pilot light
☐ Overload trip pilot light
☐ Elapsed time meter
☐ Ammeter
☑ Overload reset button
11.6.2 Where different door-mounted devices are indicated for a unit on the motor control center schedule, those devices shall be furnished on that unit in place of the datasheet selection.
11.6.3 The run pilot light color shall be as indicated in the datasheet.
Run Pilot Light Colorradio
○ Red
○ Green
NOTE Two conventions are in use and each is coherent on its own terms: one uses red for running because a running motor is the energized and hazardous state, and green for stopped; the other uses green for running and red for stopped or tripped, following the traffic convention. The colors need to match the convention already used in the facility and in the control system graphics, which is why the field asserts no default. (11.6.4)
11.6.5 The pilot light type shall be as indicated in the datasheet.
Pilot Light Typeradio
● LED, push-to-test
○ Incandescent, transformer type
11.6.6 Each starter unit shall be furnished with not fewer than one normally open and one normally closed spare auxiliary contact on the contactor, wired to the unit terminal blocks where terminal blocks are furnished.

11.7 Feeder Units

11.7.1 Feeder units shall be furnished where indicated on the motor control center schedule.
11.7.2 The feeder unit device type shall be as indicated in the datasheet.
Feeder Unit Device Typeselect
Thermal-magnetic circuit breaker
Electronic-trip circuit breaker
Fusible disconnect switch
NOTE A feeder unit serves a load that is not a motor controlled from the assembly, such as a panelboard, a transformer, or a packaged equipment item with its own controller, and its device is selected for that load rather than for a motor. (11.7.3)
11.7.4 Feeder unit devices shall be rated for the available fault current at the unit or shall be part of a series-rated combination where series rating is the assembly rating basis.

11.8 Variable Frequency Drive Units

11.8.1 Variable frequency drive units shall be furnished where indicated on the motor control center schedule, and the drive performance, harmonic treatment, bypass arrangement, and configuration shall comply with HVAC Variable Frequency DrivesHVAC Variable Frequency DrivesResolves to the current adopted revision.sync/hvac-variable-frequency-drives.
11.8.2 Each drive unit shall be listed to UL 61800-5-1 and installed by the manufacturer in a unit of its own construction, with the cooling the drive needs at full output current at the design ambient temperature of the assembly.
11.8.3 A drive whose heat dissipation exceeds what a plug-in compartment can ventilate shall be furnished in a frame-mounted unit with forced ventilation, and the manufacturer shall identify each such unit on the unit arrangement drawings.
11.8.4 Each drive unit shall have its own unit disconnect, interlocked with the unit door in the same manner as a starter unit.

11.9 Metering Units

11.9.1 The metering furnished in the assembly shall be as indicated in the datasheet.
Metering Extentselect
No metering
Main incoming metering
Main incoming and feeder unit metering
Main incoming and per-motor metering
11.9.2 Meters and their current transformers shall comply with Electrical Power MonitoringElectrical Power Monitoring and MeteringResolves to the current adopted revision.sync/electrical-power-monitoring, and shall be installed by the manufacturer in a unit or an instrument compartment of the manufacturer's construction.
NOTE Per-motor metering makes each motor's power and energy visible for commissioning, fault diagnosis, and measurement and verification, at the cost of a meter and current transformers in every unit; where an electronic overload relay with a network interface is furnished, it already reports current and can report power on some models, which covers much of what per-motor metering is bought for. (11.9.3)
11.9.4 Where Adopted Energy CodeAdopted Energy CodeParameterEach project supplies its own value.adopted-energy-code requires the motor loads served from the assembly to be submetered, the metering shall accumulate energy for those loads and shall report it to the building automation system.

12 Communications

12.1 Network Protocol

12.1.1 The communications protocol of the assembly network shall be as indicated in the datasheet.
Communications Protocolselect
No network
Modbus RTU
Modbus TCP
EtherNet/IP
PROFINET
PROFIBUS DP
DeviceNet
BACnet/IP
BACnet MS/TP
NOTE The protocol has to match the system the assembly reports to; an assembly serving building mechanical equipment reports to the building automation system under Building Automation SystemBuilding Automation SystemResolves to the current adopted revision.sync/building-automation-system, and one serving process equipment reports to the control system under Process Control NetworksProcess Control NetworksResolves to the current adopted revision.sync/process-control-networks. (12.1.2)
12.1.3 Where a network is furnished, the devices connected to it shall be as indicated in the datasheet.
Networked Devicescheckbox
☐ Electronic overload relays
☐ Soft starters
☐ Variable frequency drives
☐ Meters
☐ Main circuit breaker trip unit
☐ Feeder unit electronic trip units
12.1.4 Where a network is furnished, the network topology within the assembly shall be as indicated in the datasheet.
Network Topologyradio
○ Single segment
○ Segmented by device type
○ Redundant ring
NOTE A single segment is the least equipment and the arrangement most assemblies are built with; segmenting keeps the high-traffic drives and meters off the segment the overload relays share; a redundant ring, using managed switches that support a ring protocol, keeps every device reachable after a single cable or switch failure, at the cost of managed switches and the configuration they need. (12.1.5)
12.1.6 Where a network is furnished, the network cable, the switches, the terminations, and the power supplies for the network shall be installed by the manufacturer within the assembly, and the network shall be brought to a terminal or a connector in a designated compartment for the field connection.
12.1.7 Network cable inside the assembly shall be routed separately from the power conductors, and where it must cross a power conductor it shall cross at a right angle.
12.1.8 Each networked device shall be assigned an address on the network address list submitted with the action submittals, and the address shall be marked inside the unit.

13 Identification

13.1 Nameplates shall be furnished on the assembly, on each vertical section, and on each unit, and shall comply with Electrical IdentificationElectrical IdentificationResolves to the current adopted revision.sync/electrical-identification for material, lettering, and attachment.
13.2 The assembly nameplate shall state the assembly designation, the system voltage, the horizontal bus rating, the assembly short-circuit current rating, the series-rated combinations where series rating is the basis, and the source that feeds the assembly.
13.3 Each unit nameplate shall state the unit designation, the load served, and for a starter unit the motor horsepower and full-load current, in the text listed on the nameplate schedule.
13.4 The unit designation on the nameplate shall match the designation on the motor control center schedule, on the disconnect at the motor, and on the motor itself.
NOTE A unit designation that differs between the assembly, the schedule, and the motor is the most common cause of a lockout applied to the wrong unit, which is why the three are required to agree. (13.5)
13.6 The available fault current and the date it was calculated shall be marked on the assembly in accordance with NFPA 70 110.24 where the assembly is service entrance equipment.

14 Testing

14.1 Factory Tests

14.1.1 The manufacturer shall perform the production tests of UL 845 and NEMA ICS 18 on the completed assembly, including a dielectric withstand test of the bus, a continuity check of every control circuit against the schematic diagrams, a mechanical operation check of every unit and door interlock, and a functional check of every unit.
14.1.2 Factory acceptance test witnessing shall be as indicated in the datasheet.
Factory Acceptance Test Witnessingradio
○ Witnessed by the Owner's representative
● Unwitnessed with a certified test report
14.1.3 Where witnessed testing is indicated, the manufacturer shall give the Owner not less than two weeks notice of test readiness, and the test procedure shall have been submitted and returned before the test date.
NOTE A witnessed test lets the Owner see every unit operate and every interlock work before the assembly ships, and it commits a representative to a trip to the factory; a certified report records the same tests without the trip, and leaves any discrepancy to be found at field acceptance testing instead. (14.1.4)

14.2 Field Acceptance Tests

14.2.1 Field acceptance testing shall be performed after installation is complete and before the assembly is energized, in accordance with ANSI/NETA ATS Section 7.16 and with Electrical Acceptance TestingElectrical Acceptance TestingResolves to the current adopted revision.sync/electrical-acceptance-testing.
14.2.2 Field acceptance tests shall include, at minimum:
  • visual and mechanical inspection of every section and unit, including bus splice bolt torque against the manufacturer's values
  • insulation resistance of the horizontal and vertical bus, phase-to-phase and phase-to-ground, with each unit withdrawn
  • contact resistance of every bolted bus joint
  • insertion and withdrawal of every plug-in unit, with the ground stab verified to engage first and release last
  • functional operation of every unit disconnect and door interlock
  • primary current injection of every overload relay at one point on its trip curve, or secondary injection where the relay accepts it
  • functional test of every starter, soft starter, and drive unit through its control circuit
  • verification of every networked device at its address
  • functional test of every interlock, alarm, and remote control point against the control diagrams
14.2.3 A unit or a joint that fails an acceptance test shall be corrected and retested, and the cost of the correction and the retest shall be borne by the Contractor.
14.2.4 Manufacturer start-up shall be provided where indicated in the datasheet.
Manufacturer Start-Upradio
○ Manufacturer's field service present at energization and start-up
○ Not required
14.2.5 Infrared thermographic inspection shall be as indicated in the datasheet.
Infrared Thermographic Inspectionselect
Not required
One inspection within 90 days of energization
One inspection within 90 days of energization and a second at eleven months
14.2.6 Where infrared inspection is indicated, it shall be performed with the assembly carrying not less than 40% of its rated load on each scanned circuit, and every connection showing a rise of more than 10 °C above its neighbors shall be reported and corrected.
NOTE A second inspection near the end of the first year finds the joint that loosened through the first full cycle of seasonal load, which the first inspection cannot see; it costs a second visit under load and a warranty claim filed before the warranty ends. (14.2.7)

15 Installation

15.1 Foundation and Anchorage

15.1.1 The assembly shall be set on a concrete housekeeping pad of the height indicated in the datasheet, extending not less than 3 in. beyond the assembly base on every side.
Housekeeping Pad Heightrange
in.
346
NOTE A pad keeps the base of the assembly above a wet floor and gives the anchors something to bite into that is not the slab's reinforcing; a pad height of zero is the direct-to-slab installation used where the floor is a raised platform or the anchors go into a slab designed for them. (15.1.2)
15.1.3 The assembly shall be anchored to the pad as indicated on the seismic anchorage details, using the anchor type, size, and embedment stated there.
15.1.4 Where seismic qualification is required, the anchorage shall be that on which the qualification depends, and a substitute anchor shall not be used without the manufacturer's written confirmation that the qualification remains valid.
15.1.5 Pad dimensions, conduit stub-up locations, and anchor locations shall be coordinated with the shop drawings before the pad is placed.

15.2 Setting and Assembly

15.2.1 Shipping sections shall be set, aligned, and bolted together in accordance with the manufacturer's instructions, and the horizontal bus, the neutral bus, and the ground bus shall be spliced at every shipping split with the manufacturer's splice hardware torqued to the manufacturer's values with a calibrated tool.
15.2.2 Every shipping brace, block, and desiccant shall be removed before the units are inserted.
15.2.3 Each plug-in unit shall be inserted, latched, and withdrawn once before energization to confirm free operation and positive stab engagement.
15.2.4 The Contractor shall verify that every unit compartment is occupied by a unit, a blank cover, or a shutter before the assembly is energized.

15.3 Field Wiring

15.3.1 Power and control conductors shall comply with Conductors And CablesConductors and CablesResolves to the current adopted revision.sync/conductors-and-cables and shall enter the assembly only through the wireway areas designated on the shop drawings.
15.3.2 Raceways shall comply with Raceways And ConduitRaceways and ConduitResolves to the current adopted revision.sync/raceways-and-conduit.
15.3.3 Every field termination shall be torqued to the device manufacturer's published value with a calibrated tool, and the torque values applied shall be recorded in the field test report.
15.3.4 Field conductor labels at every unit shall match the conductor designations on the schematic diagrams and the unit designation on the nameplate.

15.4 Working Space

15.4.1 Working space in front of the assembly, and behind and beside it where it is accessible there, shall comply with NFPA 70 110.26 for the system voltage and the accessibility of the assembly.
15.4.2 The dedicated electrical space above the assembly required by NFPA 70 110.26(E) shall be kept clear of piping, ductwork, and equipment not associated with the assembly.
15.4.3 Working space shall not be used for storage at any time.

16 Delivery, Storage, and Handling

16.1 The assembly shall be shipped in the largest sections that the route from the delivery point to the final location will pass, and the Contractor shall verify door, corridor, and hoistway dimensions along that route before the shipping splits are fixed on the shop drawings.
16.2 Each shipping section shall be lifted only at the lifting provisions the manufacturer furnishes, with the units installed and latched.
16.3 The assembly shall be stored indoors, in a clean, dry location protected from construction dust and from water, and shall be kept covered until it is set.
16.4 Where the assembly must be stored for more than 30 days or in a space that is not conditioned, the space heaters shall be connected to a temporary supply and energized for the duration of storage.
16.5 An assembly that has been wetted in transit or in storage shall be dried, inspected by the manufacturer's field service organization, and released in writing before it is energized.

17 Warranty

17.1 The manufacturer shall warrant the assembly, its bus, and every factory-installed unit and device against defects in materials and workmanship for the period indicated in the datasheet.
Warranty Periodrange
years
1235
17.2 The warranty period shall commence on the date indicated in the datasheet.
Warranty Commencementselect
Date of substantial completion
Date of energization
Date of shipment
NOTE Warranty commencement at shipment is the manufacturer's usual term, and it consumes the warranty during storage and construction; commencement at energization or substantial completion moves the coverage to the period the Owner is operating the equipment, and the manufacturer prices the added months into the assembly. (17.3)
17.4 The warranty coverage scope shall be as indicated in the datasheet.
Warranty Coverage Scoperadio
○ Parts only
○ Parts and labor
17.5 A warranty repair shall include the replacement unit or device, its installation where labor is covered, and the retest of the affected unit, and shall not reduce the coverage of any other unit in the assembly.
17.6 A unit or device replaced under warranty shall be warranted for the remainder of the original period or for one year from the date of replacement, whichever ends later.
17.7 The manufacturer shall provide a replacement plug-in unit for a unit that fails under warranty within the response time stated in the qualification statement.

18 Spare Parts

18.1 Spare Units

18.1.1 The spare plug-in units furnished shall be as indicated in the datasheet, and shall be delivered before the assembly is accepted.
Spare Plug-In Unitscheckbox
☐ One spare full-voltage non-reversing starter unit of each size installed
☐ One spare full-voltage reversing starter unit of each size installed
☐ One spare soft starter unit of the largest size installed
☐ One spare drive unit of the largest size installed
☐ One spare feeder unit of each frame installed
18.1.2 The spare unit space reserved in each vertical section shall be not less than the share indicated in the datasheet.
Spare Unit Space per Sectionrange
%
1020253350
NOTE Spare space is the compartment height left empty, with bus stab openings shuttered and doors installed, so that a unit can be added later without a new section; it costs floor length at the time of purchase and saves a section, a bus splice, and a shutdown at the time of the addition. (18.1.3)
18.1.4 Spare space shall be furnished with the vertical bus, the wireway, the doors, and the shutters or blanking covers in place, ready to receive a unit.

18.2 Spare Components

18.2.1 The spare components furnished shall be as indicated in the datasheet, and shall be delivered before the assembly is accepted.
Spare Componentscheckbox
☑ One spare overload relay of each rating installed
☐ One spare control power transformer of each rating installed
☑ One set of fuses of each type and rating installed
☑ One set of pilot lights and lenses of each type installed
☐ One set of pushbutton and selector switch operators of each type installed
☐ One unit withdrawal handle and one set of blanking covers
18.2.2 Spare units and components shall be identical to and interchangeable with the installed items, shall be delivered in their original packaging, and shall be labeled with the unit designation or the device rating they serve.
18.2.3 The Contractor shall obtain a signed receipt from the Owner for the spare units and components delivered.