900-volt, dielectric strength test (with all switches closed) between live parts (including neutral conductor) and
the mobile home ground. Alternatively, the test shall be permitted to be performed at 1080 volts for 1 second. This test shall be performed after branch circuits are complete and after luminaires or appliances are installed.
Exception: Listed luminaires or appliances shall not be required to withstand the dielectric strength test.
(B) Continuity and Operational Tests and Polarity Checks. Each mobile home shall be subjected to all of the following:
(1) An electrical continuity test to ensure that all exposed electrically conductive parts are properly bonded
(2) An electrical operational test to demonstrate that all equipment, except water heaters and electric furnaces, is connected and in working order
(3) Electrical polarity checks of permanently wired equipment and receptacle outlets to determine that connections have been properly made
550.18 Calculations. The following method shall be em ployed in calculating the supply-cord and distribution- panelboard load for each feeder assembly for each mobile home in lieu of the procedure shown in Article
220 and shall be based on a 3-wire, 120/240-volt supply with 120-volt loads balanced between the two ungrounded conductors of the 3-wire system.
Nameplate Rating Use
(watts) (volt-amperes)
0 - 10,000 80 percent of rating
Over 10,000- 12,500 8,000
Over 12,500- 13,500 8,400
Over 13,500- 14,500 8,800
Over 14,500 - 15,500 9,200
Over 15,500 - 16,500 9,600
Over 16,500 - 17,500 10,000
550.19 Interconnection of Multiple-Section Mobile or
Manufactured Home Units.
(A) Wiring Methods. Approved and listed fixed-type wir ing methods shall be used to join portions of a circuit that must be electrically joined and are located in adjacent sections after the home is installed on its support foundation. The circuit's junction shall be accessible for disassembly when the home is prepared for relocation.
FPN: See 550.15(K) for component interconnections.
(B) Disconnecting Means. Expandable or multiunit manufactured homes, not having permanently installed feeders, that are to be moved from one location to another shall be permitted to have disconnecting means with branch-circuit protective equipment in each unit when so located that after assembly or joining together of units, the requirements of 550.10 will be met.
550.20 Outdoor Outlets, Luminaires, Air-Cooling
Equipment, and So Forth.
(A) Listed for Outdoor Use. Outdoor luminaires and equipment shall be listed for wet locations or outdoor use. Outdoor receptacles shall comply with 406.8. Where located on the underside of the home or located under roof extensions or similarly protected locations, outdoor luminaires and equipment shall be listed for use in damp locations.
(B) Outside Heating Equipment, Air-Conditioning Equip- ment, or Both. A mobile home provided with a branch circuit designed to energize outside heating equipment, air-conditioning equipment, or both, located outside the mobile home, other than room air conditioners, shall have such branch-circuit conductors terminate in a listed outlet box, or disconnecting means, located on the outside of the mobile home. A label shall be permanently affixed adjacent to the outlet box and shall contain the following information:
THIS CONNECTION IS FOR HEATING AND/OR AIR-CONDITIONING EQUIPMENT. THE BRANCH CIRCUIT IS RATED