What percentage of the branch circuit must the total load of a window air conditioner not exceed?

(a) The number of branch circuits required shall be determined in accordance with the following:

(1) Lighting, based on 3 volt-amperes per square foot times outside dimensions of the manufactured home (coupler excluded) divided by 120 volts times amperes to determine number of 15 or 20 ampere lighting area circuits. e.g. [3 × length × width - [120 × (15 or 20)] = number of 15 or 20 ampere circuits. Lighting circuits are permitted to serve built-in gas ovens with electric service for lights, clocks, or timers, or for listed cord-connected garbage disposal units.

(2) Small Appliances. For the small appliance load in kitchens, pantries, dining rooms, and breakfast rooms of manufactured homes, two or more 20-ampere appliance branch circuits, in addition to the branch circuit specified in paragraph (a)(1) of this section, must be provided for all receptacle outlets in these rooms, and such circuits must have no other outlets. Countertop receptacle outlets installed in the kitchen must be supplied by not less than two small appliance branch circuits. One or more of the small appliance branch circuits may also supply other receptacle outlets in the kitchen, pantry, dining room, and breakfast room. Receptacles installed solely for the electrical supply to an electric clock and receptacles installed to provide power for supplemental equipment and lighting on gas-fired ranges, ovens, or counter-mounted cooking units are not subject to the requirements of this paragraph (a)(2).

(3) General appliances (Including furnace, water heater, range, and central or room air conditioner, etc.). There shall be one or more circuits of adequate rating in accordance with the following:

(i) The ampere rating of fixed appliances must not exceed 50 percent of the circuit rating if lighting outlets are on the same circuit (receptacles in the kitchen, dining area, and laundry are not considered to be lighting outlets);

(ii) For fixed appliances on a circuit without lighting outlets, the sum of rated amperes shall not exceed the branch-circuit rating. Motor loads or other continuous duty loads shall not exceed 80 percent of the branch circuit rating.

(iii) The rating of a single cord and plug connected appliances on a circuit having no other outlets, shall not exceed 80 percent of the circuit rating.

(iv) The rating of the range branch circuit is based on the range demand as specified for ranges in § 3280.811(a)(5). For central air conditioning, see Article 440 of the National Electrical Code, NFPA No. 70-2005.

(v) Where a laundry area is provided, a 20 ampere branch circuit shall be provided to supply laundry receptacle outlets. This circuit shall have no other outlets. See § 3280.806(a)(7).

(vi) Bathroom receptacle outlets must be supplied by at least one 20-ampere branch circuit. Such circuits must have no other outlets, except that it is permissible to place the receptacle outlet for a heat tape or pipe heating cable required by § 3280.806(d)(10) on a bathroom circuit. (See § 3280.806(b).)

(b) [Reserved]

[40 FR 58752, Dec. 18, 1975. Redesignated at 44 FR 20679, Apr. 6, 1979, as amended at 58 FR 55020, Oct. 25, 1993; 70 FR 72051, Nov. 30, 2005; 78 FR 73991, Dec. 9, 2013]

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(a) All receptacle outlets shall be:

(1) Of grounding type;

(2) Installed according to Article 406.3 of the National Electrical Code, NFPA No. 70-2005.

(3) Except when supplying specific appliances, be parallel-blade, 15-ampere, 125-volt, either single or duplex.

(b) All 125-volt, single-phase, 15- and 20-ampere receptacle outlets installed outdoors, or in compartments accessible from outside the manufactured home, and in bathrooms, including receptacles in light fixtures, must have ground-fault circuit-interrupter protection for personnel. Ground-fault circuit-interrupter protection for personnel must be provided for receptacles serving countertops in kitchens and receptacle outlets located within 6 feet of a wet bar sink, except for receptacles installed for appliances in dedicated spaces, such as dishwashers, disposals, refrigerators, freezers, and laundry equipment.

(d) Receptacle outlets required. Except in the bath, closet, and hall areas, receptacle outlets must be installed at wall spaces 2 feet or more wide, so that no point along the floor line is more than 6 feet, measured horizontally, from an outlet in that space. Receptacle outlets in floors shall not be counted as part of the required number of receptacle outlets, unless located within 18 inches of the wall. In addition, a receptacle outlet must be installed in the following locations:

(1) Over or adjacent to counter tops in the kitchen (at least one on each side of the sink if counter tops are on each side and 12 inches or over in width).

(2) Adjacent to the refrigerator and free-standing gas-range space. A duplex receptacle may serve as the outlet for a countertop and a refrigerator.

(3) At counter top spaces for built-in vanities.

(4) At counter top spaces under wall-mounted cabinets.

(5) In the wall, at the nearest point where a bar type counter attaches to the wall.

(6) In the wall at the nearest point where a fixed room divider attaches to the wall.

(7) In laundry areas within 6 feet of the intended location of the appliance(s).

(8) At least one receptacle outlet shall be installed outdoors.

(9) At least one wall receptacle outlet shall be installed in bathrooms within 36 inches (914 mm) of the outside edge of each basin. The receptacle outlet must be located on a wall that is adjacent to the basin location. This receptacle is in addition to any receptacle that is part of a lighting fixture or appliance. The receptacle must not be enclosed within a bathroom cabinet or vanity.

(10) On the underside of the home for the connection of pipe heating cable(s) or heat tape(s), and the outlet must:

(i) Be located within 2 feet of the cold water inlet;

(ii) Be connected to an interior branch circuit, other than a small appliance branch circuit;

(iii) Be located on a circuit where all of the outlets are on the load side of the ground-fault circuit-interrupter protection for personnel; and

(iv) Not be considered as the receptacle outlet required by paragraph (8) of this section.

(11) Receptacle outlets are not required in the following locations:

(i) Wall space occupied by built-in kitchen or wardrobe cabinets,

(ii) Wall space behind doors which may be opened fully against a wall surface,

(iii) Room dividers of the lattice type, less than 8 feet long, not solid within 6 inches of the floor,

(iv) Wall space afforded by bar type counters.

(e) Receptacle outlets shall not be installed in or within reach (30 inches) of a shower or bathtub space.

(f) Receptacle outlets shall not be installed above electric baseboard heaters.

(g) Receptacles must not be in a face-up position in any countertop.

[40 FR 58752, Dec. 18, 1975. Redesignated at 44 FR 20679, Apr. 6, 1979, as amended at 58 FR 55020, Oct. 25, 1993; 70 FR 72052, Nov. 30, 2005; 78 FR 73991, Dec. 9, 2013]

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§ 3280.807 Fixtures and appliances.

(a) Electrical materials, devices, appliances, fittings, and other equipment installed, intended for use in, or attached to the manufactured home shall be approved for the application and shall be connected in an approved manner when in service. Facilities shall be provided to securely fasten appliances when the manufactured home is in transit. (See § 3280.809.)

(b) Specifically listed pendant-type fixtures or pendant cords shall be permitted in manufactured homes.

(c) Where a lighting fixture is installed over a bathtub or in a shower stall, it must be listed for wet locations. [See also Article 410.4(D) of the National Electrical Code NFPA No. 70-2005.]

(d) The switch for shower lighting fixtures and exhaust fans located over a tub or in a shower stall shall be located outside the tub shower space. (See § 3280.806(e).)

(e) Any combustible wall or ceiling finish exposed between the edge of a fixture canopy, or pan and an outlet box shall be covered with non-combustible or limited combustible material.

(f) Every appliance shall be accessible for inspection, service, repair, or replacement without removal of permanent construction.

(g) In bathrooms, ceiling-mounted lighting fixtures and wall-mounted lighting fixtures must not be controlled by the same switch.

[40 FR 58752, Dec. 18, 1975. Redesignated at 44 FR 20679, Apr. 6, 1979, as amended at 52 FR 35543, Sept. 22, 1987; 58 FR 55020, Oct. 25, 1993; 70 FR 72052, Nov. 30, 2005; 78 FR 73991, Dec. 9, 2013; 86 FR 2523, Jan. 12, 2021]

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(a) Except as specifically permitted by this part, the wiring methods and materials specified in the National Electrical Code, NFPA No. 70-2005, must be used in manufactured homes.

(b) Nonmetallic outlet boxes shall be acceptable only with nonmetallic cable.

(c) Nonmetallic cable located 15 inches or less above the floor, if exposed, shall be protected from physical damage by covering boards, guard strips, or conduit. Cable likely to be damaged by stowage shall be so protected in all cases.

(d) Nonmetallic sheathed cable shall be secured by staples, straps, or similar fittings so designed and installed as not to injure any cable. Cable shall be secured in place at intervals not exceeding 4 1/2 feet and within 12 inches from every cabinet, box or fitting.

(e) Metal-clad and nonmetallic cables shall be permitted to pass through the centers of the wide side of 2-inch by 4-inch studs. However, they shall be protected where they pass through 2-inch by 2-inch studs or at other studs or frames where the cable or armor would be less than 1 1/2 inches from the inside or outside surface of the studs when the wall covering materials are in contact with the studs. Steel plates on each side of the cable, or a tube, with not less than No. 16 MSG wall thickness shall be required to protect the cable. These plates or tubes shall be securely held in place.

(f) Where metal faceplates are used, they must be effectively grounded.

(g) If the range, clothes dryer, or similar appliance is connected by metalclad cable or flexible conduit, a length of not less than three feet of free cable or conduit shall be provided to permit moving the appliance. Type NM or Type SE cable shall not be used to connect a range or a dryer. This shall not prohibit the use of Type NM or Type SE cable between the branch circuit overcurrent protective device and a junction box or range or dryer receptacle.

(h) Where rigid metal conduit or intermediate metal conduit is terminated at an enclosure with a locknut and bushing connection, two locknuts must be provided, one inside and one outside of the enclosure. Rigid nonmetallic conduit or electrical nonmetallic tubing is permitted. All cut ends of conduit and tubing must be reamed or otherwise finished to remove rough edges.

(i) Switches must be rated as follows:

(1) For lighting circuits, switches must be rated not less than 10 amperes, 120 to 125 volts, and in no case less than the connected load.

(2) For motors or other loads, switches shall have ampere or horsepower ratings, or both, adequate for loads controlled. (An “AC general-use” snap switch shall be permitted to control a motor 2 horsepower or less with full-load current not over 80 percent of the switch ampere rating).

(j) At least 4 inches of free conductor shall be left at each outlet box except where conductors are intended to loop without joints.

(k) When outdoor or under-chassis line-voltage (120 volts, nominal or higher) wiring is exposed to moisture or physical damage, it must be protected by rigid metal conduit or intermediate metal conduit. The conductors must be suitable for wet locations. Electrical metallic tubing or rigid nonmetallic conduit is permitted to be used when closely routed against frames and equipment enclosures.

(l) Outlet boxes of dimensions less than those required in Table 314.16(A) of the National Electrical Code, NFPA No. 70-2005, are permitted provided the box has been tested and approved for that purpose.

(m) Boxes, fittings, and cabinets shall be securely fastened in place, and shall be supported from a structural member of the home, either directly or by using a substantial brace. Snap-in type boxes provided with special wall or ceiling brackets that securely fasten boxes in walls or ceilings shall be permitted.

(n) Outlet boxes must fit closely to openings in combustible walls and ceilings and must be flush with the finish surface or project therefrom. In walls and ceilings of noncombustible material, outlet boxes and fittings must be installed so that the front edge of the box or fitting will not be set back from the finished surface more than 1/4 inch. Plaster, drywall, or plasterboard surfaces that are broken or incomplete must be repaired so that there will be no gaps or open spaces greater than 1/8 inch at the edge of the box or fitting.

(o) Appliances having branch-circuit terminal connections which operate at temperatures higher than 60 °C (140 °F) shall have circuit conductors as described in paragraphs (p) (1) and (2) of this section:

(1) Branch-circuit conductors having an insulation suitable for the temperature encountered shall be permitted to run directly to the appliance.

(2) Conductors having an insulation suitable for the temperature encountered may be run from the appliance terminal connections to a readily accessible outlet box placed at least one foot from the appliance. If provided, these conductors must be in a suitable raceway or Type AC or MC cable, of at least 18 inches but not more than 6 feet in length.

(p) A substantial brace for securing a box, fitting, or cabinet must be as described in the National Electrical Code, NFPA 70-2005, Article 314.23(B), or the brace, including the fastening mechanism to attach the brace to the home structure, must withstand a force of 50 lbs. applied to the brace at the intended point(s) of attachment for the box in a direction perpendicular to the surface on which the box is installed.

(q) Where the sheathing of NM cable has been cut or damaged and visual inspection reveals that the conductor and its insulation has not been damaged, it shall be permitted to repair the cable sheath with electrical tape which provides equivalent protection to the sheath.

[40 FR 58752, Dec. 18, 1975. Redesignated at 44 FR 20679, Apr. 6, 1979, as amended at 58 FR 55020, Oct. 25, 1993; 70 FR 72052, Nov. 30, 2005; 78 FR 73991, Dec. 9, 2013]

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§ 3280.809 Grounding.

(a) General. Grounding of both electrical and nonelectrical metal parts in a manufactured home shall be through connection to a grounding bus in the manufactured home distribution panelboard. The grounding bus shall be grounded through the green-colored conductor in the supply cord or the feeder wiring to the service ground in the service-entrance equipment located adjacent to the manufactured home location. Neither the frame of the manufactured home nor the frame of any appliance shall be connected to the neutral conductor in the manufactured home.

(b) Insulated neutral.

(1) The grounded circuit conductor (neutral) shall be insulated from the grounding conductors and from equipment enclosures and other grounded parts. The grounded (neutral) circuit terminals in the distribution panelboard and in ranges, clothes dryers, counter-mounted cooking units, and wall-mounted ovens shall be insulated from the equipment enclosure. Bonding screws, straps, or buses in the distribution panelboard or in appliances shall be removed and discarded. However, when service equipment is installed on the manufactured home, the neutral and the ground bus may be connected in the distribution panel.

(2) Connection of ranges and clothes dryers with 120/240 volt, 3-wire ratings shall be made with 4 conductor cord and 3 pole, 4-wire grounding type plugs, or by type AC metal clad conductors enclosed in flexible metal conduit. For 120 volt rated devices a 3-conductor cord and a 2-pole, 3-wire grounding type plug shall be permitted.

(1) The green-colored grounding wire in the supply cord or permanent feeder wiring shall be connected to the grounding bus in the distribution panelboard or disconnecting means.

(2) In the electrical system, all exposed metal parts, enclosures, frames, lamp fixture canopies, etc., shall be effectively bonded to the grounding terminal or enclosure of the distribution panelboard.

(3) Cord-connected appliances, such as washing machines, clothes dryers, refrigerators, and the electrical system of gas ranges, etc., shall be grounded by means of an approved cord with grounding conductor and grounding-type attachment plug.

(d) Bonding of noncurrent-carrying metal parts.

(1) All exposed noncurrent-carrying metal parts that may become energized shall be effectively bonded to the grounding terminal or enclosure of the distribution panelboard. A bonding conductor shall be connected between each distribution panelboard and an accessible terminal on the chassis.

(2) Grounding terminals shall be of the solderless type and approved as pressure-terminal connectors recognized for the wire size used. Star washers or other approved paint-penetrating fitting shall be used to bond terminals to chassis or other coated areas. The bonding conductor shall be solid or stranded, insulated or bare and shall be No. 8 copper minimum, or equal. The bonding conductor shall be routed so as not to be exposed to physical damage. Protection can be afforded by the configuration of the chassis.

(3) Metallic gas, water and waste pipes and metallic air-circulating ducts shall be considered bonded if they are connected to the terminal on the chassis (see § 3280.809) by clamps, solderless connectors, or by suitable grounding-type straps.

(4) Any metallic roof and exterior covering shall be considered bonded if (i) the metal panels overlap one another and are securely attached to the wood or metal frame parts by metallic fasteners, and (ii) if the lower panel of the metallic exterior covering is secured by metallic fasteners at a cross member of the chassis by two metal straps per manufactured home unit or section at opposite ends. The bonding strap material shall be a minimum of 4 inches in width of material equivalent to the skin or a material of equal or better electrical conductivity. The straps shall be fastened with paint-penetrating fittings (such as screws and star washers or equivalent).

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§ 3280.810 Electrical testing.

(a) Dielectric strength test. The wiring of each manufactured home shall be subjected to a 1-minute, 900 to 1079 volt dielectric strength test (with all switches closed) between live parts and the manufactured home ground, and neutral and the manufactured home ground. Alternatively, the test may be performed at 1080 to 1250 volts for 1 second. This test shall be performed after branch circuits are complete and after fixtures or appliances are installed. Fixtures or appliances which are listed shall not be required to withstand the dielectric strength test.

(b) Additional testing. Each manufactured home must be subjected to the following tests:

(1) An electrical continuity test to assure that metallic parts are effectively bonded;

(2) An operational test of all devices and utilization equipment, except water heaters, electric ranges, electric furnaces, dishwashers, clothes washers/dryers, and portable appliances, to demonstrate they are connected and in working order; and

(3) Electrical polarity checks to determine that connections have been made in accordance with applicable provisions of these standards and Article 550.17 of NFPA 70-2005 (incorporated by reference, see § 3280.4). Visual verification is an acceptable electrical polarity check.

[58 FR 55020, Oct. 25, 1993, as amended at 86 FR 2523, Jan. 12, 2021]