Mobile Homes and Marinas

Choose the best answer:

  1. Aluminum, aluminum-alloy, and copper-clad aluminum conductors are permitted only for branch-circuit wiring in mobile and manufactured homes.
    (a) true
    (b) false

  2. All branch circuits that supply 15A and 20A, 125V outlets in bedrooms of _____ must be protected by AFCIs.
    (a) mobile homes
    (b) manufactured homes
    (c) a and b
    (d) none of these

  3. Service equipment can be mounted on or within a manufactured home.
    (a) true
    (b) false

  4. Private, noncommercial boat docking facilities _____ for use by the owner or residents of the associated single-family dwelling aren't covered by Art. 555.
    (a) constructed
    (b) occupied
    (c) a or b
    (d) none of these

  5. The electrical datum plane — land areas subject to tidal fluctuation — in a marina or boatyard is a horizontal plane _____ ft above the highest tide level under normal circumstances.
    (a) 1
    (b) 2
    (c) 3
    (d) 4

  6. A _____ is an enclosed assembly that can include receptacles, circuit breakers, fused switches, fuses, watt-hour meter(s), and monitoring means approved for marine use.
    (a) marine power receptacle
    (b) marine outlet
    (c) marine power outlet
    (d) any of these

  7. The disconnecting means for a boat must be readily accessible, not more than _____ from the receptacle it controls, and in the supply circuit ahead of the receptacle.
    (a) 12 in.
    (b) 24 in.
    (c) 30 in.
    (d) 36 in.

  8. Receptacles that provide shore power for boats must be _____.
    (a) rated not less than 30A
    (b) of the single-outlet type
    (c) of the locking and grounding-type, if rated 50A and less
    (d) all of these

Answers and Discussion

  1. (b), false. A new rule (550.15) in the 2002 NEC prohibits the use of aluminum wire in mobile and manufactured homes. This type of wire has traditionally been used to supply branch circuits for ranges, dryers, and electric furnaces.

  2. (c), a and b. A new rule (550.25) on arc-fault circuit interrupter (AFCI) protection for mobile and manufactured homes mirrors the AFCI requirements for dwelling units outlined in 210.12.

  3. (a), true. Service equipment can be installed in or on a manufactured home, provided the following conditions are met [550.32(B)].

    • The manufacturer must include in its written installation instructions indicating that the home must be secured in place by an anchoring system or installed on and secured to a permanent foundation.

    • The manufacturer must include in its written installation instructions one method of grounding the service equipment at the installation site. The instructions must clearly state that other methods of grounding are found in Art. 250.

    • A red warning label must be mounted on or adjacent to the service equipment, stating, “Warning: Do not provide electrical power until the grounding electrode(s) is installed and connected (see installation instructions).”

  4. (c), a or b. This rule was changed to clarify that the requirements of Art. 555 don't apply to boat docks at a single-family dwelling. For single-family dwellings, GFCI protection is required for all 15A and 20A, single-phase, 125V receptacles located outdoors or in boathouses [210.8(A)(3) and 210.8(A)(8)]. Although the Code doesn't define what a single-family dwelling unit is, it's safe to say a single-family dwelling unit and a single dwelling unit [Art. 100] are the same thing. Docking facilities at buildings containing more than one dwelling unit, such as duplexes, condominiums, and apartments, fall under the rules of Art. 555.

  5. (b), 2. A new definition in 555.2 ensures the proper placement of transformers [555.5], electrical connections [555.9], and shore power receptacles, in accordance with 555.19(A).

  6. (c), marine power outlet. A new definition in Art. 555.2 ensures the proper application of disconnecting means for shore power connections, in accordance with 555.17(B) and shore power receptacles, in accordance with 555.19(A).

  7. (c), 30 in. This new requirement (555.17) in the 2002 NEC was extracted from NFPA 303 — Fire Protection Standard for Marinas and Boatyards.

  8. (d), all of these. There is no specific requirement that the rating of a receptacle must be dependent on the length of the boat (555.19). Instead, the Code sets a minimum rating of 30A and leaves it up to the designer and/or owner to provide the receptacles they deem necessary based on projected usage of the slips.