1 Scope
NOTE This standard governs the selection, specification, and installation of in-floor electrical and low-voltage service assemblies for commercial and institutional occupancies. (1.1)
NOTE The assemblies covered fall into three families that differ fundamentally in how and when they are set into the floor: (1.2)
- Preset (pour-in-place) concrete floor boxes - set in the formwork before concrete is placed, with the box body cast permanently into the slab.
- Adjustable concrete floor boxes - set with a leveling collar that allows vertical adjustment after the pour to meet finish-floor elevation.
- Poke-through devices - installed by core-drilling a completed slab and inserting a listed assembly that penetrates the floor-ceiling structure from above.
NOTE Covered services include power, data, voice, and audiovisual outlets delivered through covers, service fittings, and modular inserts in single-service through multi-service housings. (1.3)
NOTE This standard applies to new construction and interior fit-out in Type I through Type V construction. (1.4)
NOTE The enclosure and service fitting are within this standard; the cable, connector, and pathway routed to it are not. (1.5)
NOTE The following scopes are excluded from this standard: wall-mounted and above-floor devices, raceway and cabling, raised-access-floor systems, under-slab vapor barriers, the rated floor-ceiling assembly itself, snow-melt cable, and non-electrical concrete embeds - each covered by its own standard. (1.6)
- Wall-mounted and above-floor receptacles, switches, GFCI devices, and device plates are specified in Wiring Devices.
- Conduit, raceway, wireway, and conductor-fill calculations feeding the boxes are specified in Raceways And Conduit.
- Horizontal cabling, telecommunications outlet modules, and the cable and connector hardware placed inside a floor box are specified in Structured Cabling; this standard sets only the number and type of insert positions the enclosure provides.
- Raised-access-floor pedestal systems and their service outlet poles are specified in Raised Access Flooring; poke-through devices are not used in raised-access-floor systems.
- Under-slab vapor barriers and slab preparation beneath floor boxes are specified in Vapor Barriers Under Slab.
- Construction and firestopping of the fire-resistance-rated floor-ceiling assembly itself - concrete topping, spray fireproofing, and penetration firestopping of other trades - are specified in Fire Rated Wall And Floor Assemblies.
- Snow-melt heating cable embedded in concrete slabs is specified in Snow Melt Systems.
- Non-electrical concrete embeds, accessories, and sleeves set before the pour are specified in Concrete Accessories.
2 Referenced Standards
2.1Equipment, materials, and installation shall comply with the latest adopted edition of each of the following unless a specific edition is cited.
2.2Where referenced standards conflict, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.
| Standard |
Title |
| NFPA 70 (NEC) Art. 314.27(C) |
Outlet Boxes - Floor Boxes (listing and cover requirements) |
| NFPA 70 (NEC) Art. 406.4(G) |
Receptacle Rating and Type - Protection of Floor Receptacles |
| NFPA 70 (NEC) Art. 314 |
Boxes, Conduit Bodies, Fittings, and Handhole Enclosures (box fill) |
| NFPA 70 (NEC) Art. 110.14(C) |
Temperature Limitations of Conductor Terminations |
| UL 514A |
Metallic Outlet Boxes |
| UL 514C |
Nonmetallic Outlet Boxes, Flush-Device Boxes, and Covers |
| UL CEYY |
Outlet Boxes and Fittings Classified for Fire Resistance (poke-through classification) |
| UL 263 / ASTM E119 |
Fire Tests of Building Construction and Materials |
| NFPA 101 (2021) §7.5 |
Life Safety Code - Means of Egress |
| ADA Standards (2010) §302 |
Floor or Ground Surfaces (accessible-route openings) |
| IBC 2021 §714 |
Penetrations of Fire-Resistance-Rated Assemblies |
3 Submittals
3.1 Action Submittals
3.1.1The Contractor shall submit the following action submittals for review before fabrication, ordering, or installation:
- Product data for each floor box, poke-through device, cover, service fitting, and modular insert, including catalog cut sheets and listing/classification marks.
- Shop drawings showing box body, cover plan, conduit hub entries, gang capacity, and the leveling/adjustment range.
- UL Fire Resistance Directory assembly design number for each fire-rated poke-through, demonstrating the device is classified for the specific floor-ceiling assembly type and hourly rating.
- Floor box layout plan keyed to the architectural and structural drawings, showing each device location, service type, and core-drill diameter.
- Cover finish and insert schedule identifying lid material, finish, and floor-finish insert (carpet, tile, terrazzo) for each location.
- Receptacle and device schedule identifying receptacle rating, GFCI provisions, and modular insert positions for each housing.
☑ Product data (boxes, poke-throughs, covers, fittings, inserts)
☑ Shop drawings (body, cover plan, hubs, gang capacity, adjustment)
☑ UL assembly design number for each fire-rated poke-through
☑ Floor box layout plan keyed to architectural/structural drawings
☐ Cover finish and insert schedule
☐ Receptacle and device schedule
3.2.1The Contractor shall submit the following informational submittals:
- Manufacturer installation instructions for each box and poke-through, including core-drill diameter, density, and spacing limits stated in the listing.
- Structural review confirmation that core-drill locations have been verified against the structural and post-tensioning drawings.
- Coordination drawings reconciling floor box locations with below-slab conduit routing and the furniture/architectural plan.
☑ Manufacturer installation instructions
☑ Structural review confirmation for core-drill locations
☑ Coordination drawings (below-slab conduit and furniture plan)
3.3 Closeout Submittals
3.3.1The Contractor shall submit the following closeout submittals:
- Record drawings showing as-installed device locations, service types, and circuit assignments.
- Operation and maintenance data covering cover removal, insert replacement, and recommended cleaning agents for the cover finish.
- Warranty documentation as required by the Warranty section.
☑ Record drawings (as-installed locations and circuits)
☑ Operation and maintenance data
☑ Warranty documentation
4 Quality Assurance
NOTE Floor boxes must be listed specifically for floor installation, not merely as general outlet boxes. (4.1)
NOTE A box that is merely listed as a general outlet box does not satisfy NEC 314.27(C); the floor-specific listing covers the crush load, moisture exposure, and cover-operation conditions unique to in-floor service. The clauses below carry the obligations. (4.2)
4.2.1Each floor box shall be listed specifically for floor installation to UL 514A (metallic) or UL 514C (nonmetallic) as applicable, and shall bear the listing mark.
4.2.2Each fire-rated poke-through device shall be UL Classified under category CEYY for fire resistance and shall bear the classification mark identifying the assembly design number for which it is classified.
4.2.3The Contractor shall not substitute a device classified for a different hourly rating or a different floor-ceiling assembly construction than the assembly in which it is installed.
NOTE Poke-through devices are UL Classified, not UL Listed. (4.3)
NOTE Poke-through fire-resistance ratings come from the UL CEYY classification program, which evaluates the device against a specific floor-ceiling assembly design number under UL 263 / ASTM E119, not from the general UL Listing mark. Specification text and submittals shall therefore use the phrase "UL Classified" for the fire rating, and the authoritative reference for valid assembly design numbers is the UL Fire Resistance Directory. (4.4)
4.4.1The installer shall be experienced in setting concrete floor boxes and core-drilled poke-through devices.
4.4.2The installer shall coordinate with the concrete and structural trades before layout is issued for construction.
5 Environmental and Service Conditions
NOTE Location class determines the cover and body construction. (5.1)
NOTE Interior dry-location boxes use a standard flush lid; slab-on-grade and other wet or damp locations require a gasketed, waterproof cover and a corrosion-resistant body. A standard interior flush-lid box is not interchangeable with a gasketed slab-on-grade box, and "weatherproof" is not a substitute for a product specifically rated for the exposure present. (5.2)
5.2.1Boxes installed in damp or wet locations, including slab-on-grade in contact with grade moisture, shall be provided with a gasketed waterproof cover and a corrosion-resistant body in accordance with NEC 314.27(C).
● Interior dry location (elevated deck, conditioned space)
○ Slab-on-grade, damp - gasketed cover
○ Wet location - gasketed waterproof cover
NOTE Cover finish and assembly ratings for floor-cleaning equipment are governed by NEC 406.4(G). (5.3)
5.3.1Floor receptacle assemblies shall permit operation of floor-cleaning equipment without damage to the receptacle or cover, in accordance with NEC 406.4(G).
5.3.2Cover assemblies in accessible routes shall comply with ADA Standards §302: openings in the cover surface shall not exceed 1/2 inch (13 mm) in any one direction, and carpet trim rings shall prevent edge uplift.
5.3.3Cover assemblies in means of egress shall not create a tripping hazard and shall comply with NFPA 101 §7.5 surface-discontinuity limits.
6 Device Type and Configuration
NOTE The device type is the first and most consequential selection because it dictates when in the construction sequence the assembly is set. (6.1)
NOTE A preset box must be located before the pour and cannot move afterward; an adjustable box tolerates finish-elevation variation; a poke-through is installed last by core-drilling a finished slab and is the only option for retrofit into an existing slab. The selection below drives the rest of the configuration. (6.2)
● Concrete preset (pour-in-place, set before pour)
○ Adjustable concrete box (leveling collar, set after pour)
○ Poke-through device (core-drilled after slab complete)
NOTE The services served determine housing size, gang capacity, and insert provisions. (6.3)
6.3.1Multi-service housings shall maintain the manufacturer's required separation between power and low-voltage compartments to limit crosstalk and comply with the device listing.
○ Power only
○ Data/voice only
● Multi-service (power + data + AV)
● Cast iron (heavy commercial)
○ Zinc die-cast
○ Stamped steel
○ Nonmetallic (for nonmetallic raceway systems)
NOTE Adjustable boxes provide a defined range of vertical travel to absorb finish-floor tolerance. (6.4)
NOTE The leveling collar lets the cover plane be brought flush after the slab is poured and the floor finish thickness is known, which is the principal reason to choose an adjustable box over a preset box. (6.5)
6.5.1Adjustable boxes shall provide vertical adjustment to set the cover flush with the finished floor.
7 Cover, Finish, and Service Head
NOTE The cover finish, profile, and floor-finish insert determine how the device reads in the finished floor. (7.1)
NOTE A recessed lid accepts a tile, terrazzo, or carpet insert so the device disappears into the floor finish; a flush metal lid is exposed. The insert recess depth must match the floor-finish material thickness, and carpet locations require a carpet flange so the carpet edge does not fray at the opening. (7.2)
7.2.1Recessed cover assemblies shall be provided with a floor-finish insert recess matched to the specified floor-finish material thickness.
7.2.2Carpet-finished locations shall be provided with a carpet flange or trim ring; carpet flanges shall not be assumed to be included with the standard box.
● Stainless steel
○ Brass
○ Nickel
○ Flush metal lid (exposed)
● Recessed lid with floor-finish insert
● Carpet (with carpet flange)
○ Tile
○ Terrazzo
○ None (exposed metal lid)
0.43750.625
Default: 0.4375 in
NOTE The service-head style shall be specified explicitly because installer defaults vary by region. (7.3)
NOTE A surface-style service head sits above the slab; a fully recessed (flush) assembly keeps the device below the finish-floor plane. Leaving this unstated risks an above-floor service head where a flush finish was required. (7.4)
7.4.1The service-head style shall be specified for each location as either surface-style or fully recessed/flush.
○ Surface-style (above-slab service head)
● Fully recessed / flush (below finish-floor plane)
8 Power Configuration
NOTE Power provisions are specified by receptacle rating, count, and GFCI requirement. (8.1)
NOTE The 80%-case commercial-office receptacle is a 20A, 125V, NEMA 5-20R duplex; 20A, 250V (NEMA 6-20R) is used for audiovisual or equipment circuits when required. Receptacle count per housing is typically two or four duplexes. (8.2)
8.2.1Each power receptacle shall be a 20A device rated for the system voltage, with conductor terminations rated for 60°C or 75°C in accordance with NEC 110.14(C).
● 20A, 125V, NEMA 5-20R (commercial office)
○ 20A, 250V, NEMA 6-20R (AV / equipment)
NOTE GFCI protection is mandatory at certain occupancies under the 2023 NEC. (8.3)
NOTE NEC 406.4(G), added in 2023, requires GFCI protection for 125V, 15A and 20A floor receptacles in food courts and passenger-transportation waiting areas. In jurisdictions that have adopted the 2023 edition this is a code requirement, not an option; projects may also require GFCI protection elsewhere by choice. (8.4)
8.4.1125V, 15A and 20A floor receptacles in food courts and passenger-transportation waiting areas shall be provided with GFCI protection in accordance with NEC 406.4(G).
○ Required (food court / transportation waiting area per NEC 406.4(G))
○ Required by project (other location)
● Not required
9 Low-Voltage and Data Configuration
NOTE The floor box specification sets the number of modular insert positions; the cable and connector are set elsewhere. (9.1)
NOTE The enclosure provides a count of modular (keystone-style) insert positions, or hardwired port provisions, for data, voice, fiber, and AV. The cable type and connector hardware that populate those positions are specified in
Structured Cabling. The insert-position count here and the connector schedule there must agree, or field conflicts arise at rough-in.
(9.2) 9.2.1The number of modular insert positions provided in the housing shall match the connector quantity scheduled in Structured Cabling for that location. 9.2.2Modular insert positions shall be confined to the low-voltage compartment of a multi-service housing, separated from the power compartment per the device listing.
10 Poke-Through Devices
NOTE Poke-through devices penetrate a completed slab and, in a rated assembly, are penetrations of a fire-resistance-rated floor-ceiling assembly governed by IBC §714. (10.1)
NOTE Because the device is installed by core-drilling a finished slab, it is the right tool for retrofit and for locations the pour-in-place layout missed. When the floor-ceiling assembly is fire-rated, the device is a penetration of that rated assembly and must be a listed/classified fire-rated penetration under IBC §714, classified for the exact assembly and hourly rating. (10.2)
10.2.1A poke-through device installed in a fire-resistance-rated floor-ceiling assembly shall be UL Classified for fire resistance and tested per UL 263 / ASTM E119 for that assembly, in accordance with IBC §714.
10.2.2The fire rating of the poke-through device shall match the UL Fire Resistance Directory assembly design number for the specific floor-ceiling assembly in which it is installed.
10.2.3A fire-rated poke-through device shall not exceed 325°F (163°C) temperature rise on the unexposed face under the UL CEYY classification fire test.
10.2.4Fire-rated poke-through devices shall be provided with the intumescent collar or firestop components required by the device classification.
NOTE The fire-rating selection is dictated by the floor-ceiling assembly's documented hourly rating, never an assumption. (10.3)
NOTE The 2-hour rating is the 80% case for a typical office floor-ceiling assembly, but the value is dictated by the assembly the structural and architectural documents specify, not by convention. (10.4)
○ Non-rated (non-fire-rated slab)
○ 1-hour
○ 1.5-hour
● 2-hour
○ 3-hour
NOTE Core-drill diameter is selected for the service density of the device. (10.5)
NOTE A 4-inch nominal core is the default for standard single- and dual-service poke-throughs in open offices; 6-inch serves heavy multi-service devices; 10-inch serves large conference and audiovisual assemblies. The core diameter shall be coordinated with the device's installation instructions. (10.6)
10.6.1The core-drill diameter shall match the manufacturer's installation instructions for the selected device and its tolerance.
● 4 in nominal (standard open-office)
○ 6 in (heavy multi-service)
○ 10 in (large conference / AV)
NOTE Poke-through density and spacing are limited by the device listing, not by the NEC. (10.7)
NOTE The manufacturer's UL listing limits the number of poke-through units to a maximum of one per 65 sq ft of floor area and requires a minimum 24 inches (610 mm) center-to-center spacing between units. These are listing limitations and are frequently overlooked on dense open-plan furniture layouts; verify the exact figures with each manufacturer's listing because they vary by product. (10.8)
10.8.1The number of poke-through units shall not exceed the manufacturer's listed density limit of one unit per 65 sq ft (6.0 m²) of floor area, or the device's published limit if more restrictive.
10.8.2Poke-through units shall be spaced not less than 24 inches (610 mm) on center, or the device's published minimum if greater.
11 Box Fill and Raceway Entry
NOTE Box fill shall be calculated for every floor box so the conductor count does not exceed the listed box volume. (11.1)
NOTE Box volume and conductor fill are governed by NEC Article 314 and Chapter 9, Table 1. The raceway feeding the box is specified in
Raceways And Conduit; this section sets only the hub provisions and the fill obligation at the box itself.
(11.2) 11.2.1Box fill shall be calculated in accordance with NEC Article 314 and NEC Chapter 9, Table 1, and the installed conductor count shall not exceed the listed volume of the box.
11.2.2Conduit hub entries shall be provided in the trade sizes required to serve the device, coordinated with the raceway method specified in Raceways And Conduit. ○ Rigid metal conduit (RMC)
● Electrical metallic tubing (EMT)
○ Flexible metallic conduit (FMC)
☑ 1/2 in
☑ 3/4 in
☐ 1 in (6 in units)
NOTE The cover crush-load rating shall meet or exceed the anticipated floor loading. (12.1)
NOTE The minimum crush-load rating under the device listing is 300 lbs; premium models are rated to 1,000 lbs. Select the rating to suit the traffic and rolling loads anticipated at the location. (12.2)
12.2.1Cover assemblies shall have a crush-load rating of not less than 300 lbs, and not less than 1,000 lbs where heavy rolling or pedestrian loads are anticipated.
● 300 lbs (minimum listed)
○ 1000 lbs (heavy traffic)
13 Installation
NOTE Coordination of device locations with the structural and MEP designs precedes layout. (13.1)
NOTE The most damaging field errors on floor boxes are coordination failures - coring through post-tensioning tendons, setting boxes at the wrong elevation, or feeding boxes from below with no clear conduit path. These are addressed by sequencing the coordination before the layout is released, as the clauses below require. (13.2)
13.2.1Core-drill locations for poke-through devices shall be reviewed against the structural and post-tensioning drawings by the Structural Engineer of Record before layout is issued for construction.
13.2.2The Contractor shall not core-drill a post-tensioned slab until the tendon layout has been verified and the core location confirmed clear of tendons.
13.2.3Floor box locations fed from below shall be coordinated with the MEP engineer to confirm a clear below-slab conduit routing in the ceiling plenum of the floor below.
13.2.4The fire rating of the floor-ceiling assembly shall be confirmed with the AHJ and the Structural Engineer of Record before poke-through device selection.
NOTE Pour-in-place boxes shall be set to the correct elevation and secured against displacement during concrete placement. (13.3)
NOTE A preset box set too low is buried by screeding; set too high it becomes a trip hazard and a finish defect. Elevation and floor-finish tolerance shall be coordinated with the concrete trade. (13.4)
13.4.1Pour-in-place boxes shall be set to the finished-slab elevation coordinated with the concrete subcontractor, accounting for slab thickness and finish tolerance.
13.4.2Pour-in-place boxes shall be secured to the formwork or deck to prevent displacement or flotation during concrete placement.
13.4.3Box openings shall be protected from concrete intrusion during the pour and cleaned before cover installation.
NOTE Device locations within the floor are shown on the drawings. (13.5)
13.5.1Floor box and poke-through device locations shall be installed as shown on the drawings floor box location plan. 13.5.2Core-drill locations in post-tensioned decks shall be installed as shown on the coordinated structural penetration plan PT penetration plan. NOTE Devices shall be installed plumb, flush, and aligned with the finished-floor plane. (13.6)
13.6.1Recessed covers shall be set flush with the finished floor within the manufacturer's tolerance, with no lip exceeding the ADA §302 surface-discontinuity limit.
13.6.2Adjustable boxes shall be leveled to the finished floor using the leveling collar before the cover is installed.
13.6.3Modular inserts and receptacles shall be installed and terminated only after slab finishing, floor-finish installation, and box cleaning are complete.
14 Testing
NOTE Each installed device shall be tested for grounding, polarity, and GFCI function before substantial completion. (14.1)
14.1.1Each power receptacle shall be tested for correct polarity and grounding continuity.
14.1.2Each GFCI-protected floor receptacle shall be tested for correct trip function in accordance with NEC 406.4(G).
14.1.3Each cover and insert shall be operated to confirm it seats flush and removes without binding.
☑ Polarity and grounding continuity at each receptacle
☑ GFCI trip test at each protected receptacle
☑ Cover and insert operation check
15 Delivery, Storage, and Handling
NOTE Boxes, covers, and inserts shall be protected from damage and contamination from delivery through final cover installation. (15.1)
15.1.1Floor boxes and poke-through devices shall be delivered in the manufacturer's original packaging with listing and classification marks intact.
15.1.2Boxes set in advance of concrete placement shall be sealed against concrete, debris, and water intrusion until the cover is installed.
15.1.3Covers, finish inserts, and modular components shall be stored indoors and installed only after floor-finish work in the area is complete to avoid finish damage.
16 Warranty
NOTE The Contractor shall provide the manufacturer's standard written warranty for floor boxes, poke-through devices, covers, and service fittings. (16.1)
16.1.1The Contractor shall warrant that floor boxes, poke-through devices, covers, and fittings are free from defects in material and workmanship for a period of not less than one year from the date of Substantial Completion.
16.1.2The fire-resistance classification of poke-through devices shall be warranted to remain valid for the installed floor-ceiling assembly for the manufacturer's published period.
17 Spare Parts
NOTE The Contractor shall furnish spare covers, inserts, and gaskets to support future maintenance. (17.1)
17.1.1The Contractor shall furnish not fewer than two spare covers of each type and finish installed on the project.
17.1.2The Contractor shall furnish a stock of spare modular inserts and gaskets sufficient to service the installed devices, as scheduled.
☑ Spare covers (2 of each type/finish)
☑ Spare modular inserts
☐ Spare gaskets (wet/damp-location covers)