Article 555

Marinas, Boatyards, and Commercial and Noncommercial Docking Facilities

  1. Scope. This article covers the installation of wiring and equipment in the areas comprising fixed or floating piers, wharves, docks, and other areas in marinas, boatyards, boat•basins, boathouses, yacht clubs, boat condominiums, docking facilities associated with one-family dwellings, two-family dwell‐ ings, multifamily dwellings, and residential condominiums; any multiple docking facility or similar occupancies; and facilities that are used, or intended for use, for the purpose of repair, berthing, launching, storage, or fueling of small craft and the moorage of floating buildings.•Informational Note: See NFPA 303-2011, Fire Protection Standardfor Marinas and Boatyards, for additional information.
  2. Definitions.Electrical Datum Plane. The electrical datum plane is defined as follows:
    1. In land areas subject to tidal fluctuation, the electrical datum plane is a horizontal plane 606 mm (2 ft) above the highest tide level for the area occurring under normal circumstances, that is, highest high tide.
    2. In land areas not subject to tidal fluctuation, the electri‐ cal datum plane is a horizontal plane 606 mm (2 ft) above the highest water level for the area occurring under normal circumstances.
    3. The electrical datum plane for floating piers and landing stages that are (a) installed to permit rise and fall response to water level, without lateral movement, and
    (b) that are so equipped that they can rise to the datum plane established for (1) or (2), is a horizontal plane 762 mm (30 in.) above the water level at the floating pier or landing stage and a minimum of 305 mm (12 in.) above the level of the deck.Marine Power Outlet. An enclosed assembly that can include equipment such as receptacles, circuit breakers, fused switches, fuses, a watt-hour meter(s), panelboards, and monitoring means approved for marine use.protective
  3. Ground-Fault Protection. The overcurrentdevices that supply the marina, boatyards, and commercial and noncommercial docking facilities shall have ground-fault protection not exceeding 30 mA.
  4. Distribution System. Yard and pier distribution systems shall not exceed 1000 volts phase to phase.
  5. Transformers. Transformers and enclosures shall be specifically approved for the intended location. The bottom of enclosures for transformers shall not be located below the elec‐ trical datum plane.

555.7 Location of Service Equipment. The service equipment for floating docks or marinas shall be located adjacent to, but not on or in, the floating structure.

  1. Electrical Connections. Electrical connections shall be located at least 305 mm (12 in.) above the deck of a floating pier. Conductor splices, within approved junction boxes, utiliz‐ ing sealed wire connector systems listed and identified for submersion shall be permitted where located above the water‐ line but below the electrical datum plane for floating piers.All electrical connections shall be located at least 305 mm (12 in.) above the deck of a fixed pier but not below the electri‐ cal datum plane.
  2. Electrical Equipment Enclosures.
    1. Securing and Supporting. Electrical equipment enclo‐ sures installed on piers above deck level shall be securely andARTICLE 555 — MARINAS, BOATYARDS, AND COMMERCIAL AND NONCOMMERCIAL DOCKING FACILITIES 555.15
      substantially supported by structural members, independent of any conduit connected to them. If enclosures are not attached to mounting surfaces by means of external ears or lugs, the internal screw heads shall be sealed to prevent seepage of water through mounting holes.
    2. Location. Electrical equipment enclosures on piers shall be located so as not to interfere with mooring lines.
  3. Circuit Breakers, Switches, Panelboards, and Marine Power Outlets. Circuit breakers and switches installed in gasketed enclosures shall be arranged to permit required manual operation without exposing the interior of the enclo‐ sure. All such enclosures shall be arranged with a weep hole to discharge condensation.
  4. Load Calculations for Service and Feeder Conductors. General lighting and other loads shall be calculated in accord‐ ance with Part III of Article 220, and, in addition, the demand factors set forth in Table 555.12 shall be permitted for each service and/or feeder circuit supplying receptacles that provide shore power for boats. These calculations shall be permitted to be modified as indicated in notes (1) and (2) to Table 555.12. Where demand factors of Table 555.12 are applied, the demand factor specified in 220.61(B) shall not be permitted.Informational Note: These demand factors may be inadequate in areas of extreme hot or cold temperatures with loaded circuits for heating, air-conditioning, or refrigerating equip‐ ment.
  5. Wiring Methods and Installation.
  1. Wiring Methods.
    1. General. Wiring methods of Chapter 3 shall be permitted where identified for use in wet locations.
    2. Portable Power Cables. Extra-hard usage portable power cables rated not less than 75°C (167°F), 600 volts; listed for both wet locations and sunlight resistance; and having an outer jacket rated to be resistant to temperature extremes, oil, gaso‐ line, ozone, abrasion, acids, and chemicals shall be permitted as follows:
      Table 555.12 Demand Factors
      1. As permanent wiring on the underside of piers (floating or fixed)
      2. Where flexibility is necessary as on piers composed of floating sections
      3. Temporary Wiring. Temporary wiring, except as permit‐ ted by Article 590, shall not be used to supply power to boats.
  2. Installation.
    1. Overhead Wiring. Overhead wiring shall be installed to avoid possible contact with masts and other parts of boats being moved in the yard.Conductors and cables shall be routed to avoid wiring closer than 6.0 m (20 ft) from the outer edge or any portion of the yard that can be used for moving vessels or stepping or unstep‐ ping masts.
    2. Outside Branch Circuits and Feeders. Outside branch circuits and feeders shall comply with Article 225 except that clearances for overhead wiring in portions of the yard other than those described in 555.13(B)(1) shall not be less than5.49 m (18 ft) abovegrade.
    3. Wiring Over and Under Navigable Water. Wiring over and under navigable water shall be subject to approval by the authority having jurisdiction.Informational Note: See NFPA 303-2011, Fire Protection Standard for Marinas and Boatyards, for warning sign requirements.
    4. Portable Power Cables.
      1. Where portable power cables are permitted by 555.13(A)(2), the installation shall comply with the following:
        1. Cables shall be properly supported.
        2. Cables shall be located on the underside of the pier.
        3. Cables shall be securely fastened by nonmetallic clips to structural members other than the deck planking.
        4. Cables shall not be installed where subject to physical damage.
        5. Where cables pass through structural members, they shall be protected against chafing by a permanently installed oversized sleeve of nonmetallic material.
      2. Where portable power cables are used as permitted in 555.13(A)(2)(2), there shall be an approved junction box of corrosion-resistant construction with permanently installed

Number of Shore Power Receptacles

Sum of the Rating of the Receptacles (%)

terminal blocks on each pier section to which the feeder and feeder extensions are to be connected. A listed marine power outlet employing terminal blocks/bars shall be permitted in


1–4 100

5–8 90

9–14 80

15–30 70

31–40 60

41–50 50

51–70 40

≥71 30

lieu of a junction box. Metal junction boxes and their covers, and metal screws and parts that are exposed externally to the boxes, shall be of corrosion-resistant materials or protected by material resistant to corrosion.

(5) Protection. Rigid metal conduit, reinforced thermosetting resin conduit (RTRC) listed for aboveground use, or rigid poly‐ vinyl chloride (PVC) conduit suitable for the location, shall be installed to protect wiring above decks of piers and landing

  1. Where shore power accommodations provide two receptacles specifically for an individual boat slip and these receptacles have different voltages (for example, one 30 ampere, 125 volt and one 50 ampere, 125/250 volt), only the receptacle with the larger kilowatt demand shall be required to be calculated.
  2. If the facility being installed includes individual kilowatt-hour submeters for each slip and is being calculated using the criteria listed in Table 555.12, the total demand amperes may be multiplied by 0.9 to achieve the final demand amperes.

stages and below the enclosure that it serves. The conduit shall be connected to the enclosure by full standard threads or fittings listed for use in damp or wet locations, as applicable.

555.15 Grounding. Wiring and equipment within the scope of this article shall be grounded as specified in Article 250 and as required by 555.15(A) through (E).

  1. Equipment to Be Grounded. The following items shall be connected to an equipment grounding conductor run with the circuit conductors in the same raceway, cable, or trench:
    1. Metal boxes, metal cabinets, and all other metal enclo‐ sures
    2. Metal frames of utilization equipment
    3. Grounding terminals of grounding-type receptacles
  2. Type of Equipment Grounding Conductor. The equip‐ ment grounding conductor shall be an insulated conductor with a continuous outer finish that is either green or green with one or more yellow stripes. The equipment grounding conductor of Type MI cable shall be permitted to be identified at terminations. For conductors larger than 6 AWG, or where multiconductor cables are used, re-identification of conductors allowed in 250.119(A)(2)b. and (A)(2)c. or 250.119(B)(2) and (B)(3) shall be permitted.
  3. Size of Equipment Grounding Conductor. The insulated equipment grounding conductor shall be sized in accordance with 250.122 but not smaller than 12 AWG.
  4. Branch-Circuit Equipment Grounding Conductor. The insulated equipment grounding conductor for branch circuits shall terminate at a grounding terminal in a remote panel‐ board or the grounding terminal in the main service equip‐ ment.
  5. Feeder Equipment Grounding Conductors. Where a feeder supplies a remote panelboard, an insulated equipment grounding conductor shall extend from a grounding terminal in the service equipment to a grounding terminal in the remote panelboard.

555.17 Disconnecting Means for Shore Power Connection(s). Disconnecting means shall be provided to isolate each boat from its supply connection(s).

  1. Type. The disconnecting means shall consist of a circuit breaker, switch, or both, and shall be properly identified as to which receptacle it controls.
  2. Location. The disconnecting means shall be readily acces‐ sible, located not more than 762 mm (30 in.) from the recepta‐ cle it controls, and shall be located in the supply circuit ahead of the receptacle. Circuit breakers or switches located in marine power outlets complying with this section shall be permitted as the disconnecting means.

555.19 Receptacles. Receptacles shall be mounted not less than 305 mm (12 in.) above the deck surface of the pier and not below the electrical datum plane on a fixed pier.

  1. Shore Power Receptacles.
    1. Enclosures. Receptacles intended to supply shore power to boats shall be housed in marine power outlets listed as marina power outlets or listed for set locations, or shall be installed in listed enclosures protected from the weather or in listed weatherproof enclosures. The integrity of the assembly shall not be affected when the receptacles are in use with any type of booted or nonbooted attachment plug/cap inserted.
    2. Strain Relief. Means shall be provided where necessary to reduce the strain on the plug and receptacle caused by the weight and catenary angle of the shore power cord.
    3. Branch Circuits. Each single receptacle that supplies shore power to boats shall be supplied from a marine power outlet or panelboard by an individual branch circuit of the volt‐ age class and rating corresponding to the rating of the recepta‐ cle.Informational Note: Supplying receptacles at voltages other than the voltages marked on the receptacle may cause overheat‐ ing or malfunctioning of connected equipment, for example, supplying single-phase, 120/240-volt, 3-wire loads from a 208Y/ 120-volt, 3-wire source.
    4. Ratings. Shore power for boats shall be provided by single receptacles rated not less than 30 amperes.Informational Note: For locking- and grounding-type recepta‐ cles for auxiliary power to boats, see NFPA 303-2011, Fire Protec‐ tion Standard for Marinas and Boatyards.
      1. Receptacles rated 30 amperes and 50 amperes shall be of the locking and grounding type.Informational Note: For various configurations and ratings of locking- and grounding-type receptacles and caps, see ANSI/ NEMA WD 6-2002 (Rev. 2008), Standard for Dimensions of Attach‐ ment Plugs and Receptacles.
      2. Receptacles rated 60 amperes or higher shall be of the pin and sleeve type.Informational Note: For various configurations and ratings of pin and sleeve receptacles, see ANSI/UL 1686, UL Standard for Safety Pin and Sleeve Configurations.
  2. Other Than Shore Power.
    1. Ground-Fault Circuit-Interrupter (GFCI) Protection for Personnel. Fifteen- and 20-ampere, single-phase, 125-volt receptacles installed outdoors, in boathouses, in buildings or structures used for storage, maintenance, or repair shall be provided with GFCI protection for personnel. Receptacles in other locations shall be protected in accordance with 210.8(B).
    2. Marking. Receptacles other than those supplying shore power to boats shall be permitted to be housed in marine power outlets with the receptacles that provide shore power to boats, provided they are marked to clearly indicate that they are not to be used to supply power to boats.
  1. Motor Fuel Dispensing Stations — Hazardous (Classi‐ fied) Locations. Electrical wiring and equipment located at or serving motor fuel dispensing locations shall comply with Arti‐ cle 514 in addition to the requirements of this article.
  2. Repair Facilities — Hazardous (Classified) Locations. Electrical wiring and equipment located at facilities for the repair of marine craft containing flammable or combustible liquids or gases shall comply with Article 511 in addition to the requirements of this article.
  3. Marine Hoists, Railways, Cranes, and Monorails. Motors and controls for marine hoists, railways, cranes, and monorails shall not be located below the electrical datum plane. Where it is necessary to provide electric power to a mobile crane or hoist in the yard and a trailing cable is utilized, it shall be a listed portable power cable rated for the conditions of use and be provided with an outer jacket of distinctive color for safety.
  4. Signage. Permanent safety signs shall be installed to give notice of electrical shock hazard risks to persons using or swimming near a boat dock or marina and shall comply with all of the following:
  1. The signage shall comply with 110.21(B)(1) and be of sufficient durability to withstand the environment.
  2. The signs shall be clearly visible from all approaches to a marina or boatyard facility.