NEC Article 555: Marinas, Boatyards, Floating Buildings, and Docking Facilities (2023 NEC)

[jar546]

Scope and Application
Article 555 of the National Electrical Code (NEC), also known as NFPA 70, governs the installation of electrical wiring and equipment in various marine environments, including fixed or floating piers, wharves, docks, floating buildings, and marinas. This includes facilities for small craft repair, berthing, launching, storage, or fueling, as well as docking facilities associated with residential buildings.

Key Definitions
Article 555 includes specific definitions for terms used within its scope, such as berth, boatyard, bulkhead, crane, docking facility, dry stack storage, marina, marina power outlet, monorail, mooring, shore power, slip, and wharf.

Electrical Datum Plane Distances

• Floating Piers: The electrical datum plane must be 30 inches above the water level and at least 12 inches above the deck.
• Tidal Areas: In areas subject to tidal fluctuations, the datum plane must be 2 feet above the highest high tide.
• Non-Tidal Areas: In areas not subject to tidal fluctuations, the datum plane must be 2 feet above the highest normal water level.

Location and Installation of Service Equipment
Service equipment must be installed on land, no closer than 5 feet horizontally from the structure it serves, and elevated at least 12 inches above the electrical datum plane. This ensures the equipment can be easily disconnected in emergencies and prevents water damage.

Maximum Voltage and Load Calculations

• Voltage Limits: Pier power distribution systems are generally limited to 250 volts phase to phase. Systems may exceed this up to 600 volts if maintained by qualified personnel.
• Load Calculations: Load calculations for service and feeder conductors must follow Part III of Article 220, with additional demand factors permitted for shore power receptacles.

Transformers and Electrical Equipment

• Transformer Requirements: Transformers must be identified for wet locations and installed above the electrical datum plane.
• Motor Controls: Motors and controls for marine hoists, cranes, and monorails must be installed above the electrical datum plane and use suitable portable power cables.

Safety Signage and Hazardous Locations

• Safety Signs: Permanent signs warning of electrical shock hazards must be installed and visible from all approaches to the facility. Signs must state, “WARNING — POTENTIAL SHOCK HAZARD — ELECTRICAL CURRENTS MAY BE PRESENT IN THE WATER.”
• Hazardous Locations: Electrical wiring and equipment at motor fuel dispensing stations and repair facilities must comply with Articles 514 and 511, respectively.

Bonding and Equipotential Planes

• Bonding Requirements: Non-current-carrying metal parts must be bonded using solid copper conductors, ensuring safety by mitigating electrical potential differences.
• Equipotential Planes: Required adjacent to outdoor service equipment or disconnecting means to prevent step and touch voltages.

Electrical Equipment and Connections

• Equipment Installation: Electrical components must be installed at least 12 inches above the deck and not below the electrical datum plane. Splices must use sealed wire connector systems identified for submersion.
• Replacements: Replacement connections must adhere to the same elevation and protection standards.

Receptacles and Wiring Methods

• Shore Power Receptacles: Must be mounted at least 12 inches above the deck and enclosed in listed marina power outlets or weather-protected enclosures. Each receptacle must be supplied by an individual branch circuit.
• Portable Power Cables: Permitted where flexibility is necessary, and must be supported, secured, and protected from physical damage.

Ground-Fault Protection

• Feeder Protection: Listed GFPE rated not more than 100 milliamperes is required for feeders on docking facilities.
• Shore Power Receptacles: Must have GFPE rated not more than 30 milliamperes.
• Leakage Current Measurement: Devices for measuring leakage current must be available where more than three shore power receptacles are used.

Disconnecting Means

• Shore Power Disconnection: Each boat must have a disconnecting means, such as a circuit breaker or switch, within 30 inches of the receptacle.
• Emergency Disconnect: Each marina power outlet must have a listed emergency shutoff device that is clearly marked and accessible.

Grounding Requirements

• Equipment Grounding Conductors: Must be wire-type, insulated, and properly terminated. Grounding of both electrical and nonelectrical parts in floating buildings is required.
• Identification: The equipment grounding conductor must be green or green with yellow stripes.

Floating Buildings

• Service and Feeder Conductors: Each floating building must be supplied by a single set of feeder conductors. Flexibility in the wiring system must be maintained to accommodate water level changes.
• Ground-Fault Protection: The main overcurrent protective device must have ground-fault protection not exceeding 100 mA. Branch-circuit GFCI devices are required for outlets rated 240 volts or less.

 

[Mark K]

The structural prescriptions in the ICC codes assume that the structure is connected to the earth.

 

[jar546]

The structural prescriptions in the ICC codes assume that the structure is connected to the earth.

The second you connect it to shore power, it is.

 

[Mark K]

The second you connect it to shore powe

The second you connect it to shore power, it is.

So when a ship connects to shore power it is subject to the building code? Interesting

 

[jar546]

So when a ship connects to shore power it is subject to the building code? Interesting

Although the NEC does not cover electrical installations on ships or watercraft, it does cover installations for floating buildings. Floating buildings are permanently moored in one location, for example, restaurants, aquariums, and dwelling units. All other applicable articles apply to these floating buildings.

For the scope statement on floating buildings covered by the NEC, see 90.2(A)(1). For the scope statement on ships and watercraft (other than floating buildings) not covered by the NEC, see and see 90.2(B)(1).

Mark, are you in a mood to troll today?

 

[ICE]

Ground-Fault Protection

• Feeder Protection: Listed GFPE rated not more than 100 milliamperes is required for feeders on docking facilities.
• Shore Power Receptacles: Must have GFPE rated not more than 30 milliamperes.
• Leakage Current Measurement: Devices for measuring leakage current must be available where more than three shore power receptacles are used.

I have not inspected anything that is regulated by NEC Article 555, and probably never will. The 100 and 30 milliamper ratings caught my attention. The 30 MA is for a 30 amp shore receptacle for plugging in a boat. The 100 MA protects feeders and branch circuits installed on docking facilities. Knowing that a Class A GFCI is rated to operate between 3 and 5 milliampers, I am wondering what or who will benefit from 30 to 100 milliamper protection.


(B) Leakage Current Measurement Device. Where more than three receptacles supply shore power to boats, a leakage current measurement device shall be available and be used to determine leakage current from each boat that will utilize shore power.

I found the informational note to be interesting.

Informational Note No. 1: Leakage current measurement will provide the capability to determine when an individual boat has defective wiring or other problems contributing to hazardous voltage and current. The use of a test device will allow the facility operator to identify a boat that is creating problems. In some cases a single boat may cause an upstream GFPE device protecting a feeder to operate even though multiple boats are supplied from the same feeder. The use of a test device will help the facility operator prevent a particular boat from contributing to hazardous voltage and current in the marina area.
Informational

Note No. 2: An annual test of each boat with the leakage current measurement device is a prudent step toward determining if a boat has defective wiring that may be contributing hazardous voltage and current. Where the leakage current measurement device reveals that a boat is contributing hazardous voltage and current, repairs should be made to the boat before it is permitted to utilize shore power.

 

[jar546]

I have not inspected anything that is regulated by NEC Article 555, and probably never will. The 100 and 30 milliamper ratings caught my attention. The 30 MA is for a 30 amp shore receptacle for plugging in a boat. The 100 MA protects feeders and branch circuits installed on docking facilities. Knowing that a Class A GFCI is rated to operate between 3 and 5 milliampers, I am wondering what or who will benefit from 30 to 100 milliamper protection.

I had an entire 8-hour class on this from an electrical engineer who specialized in NEC 555 and designed these systems for a living. There are many scenarios out there where this works and many factors to take into consideration, especially if it is in freshwater, which is more dangerous than salt or brackish water.

One of the things we found out is that the boaters were pissed because the GFCIs would trip all the time for two reasons:
1) The electrician did not know what they were doing and installed regular GFCI protection.
2) This brought to light the fact that their boats had electrical issues they were unaware of, which was causing the 30ma GFI to trip.

This can be a very long and complicated discussion. I already need a refresher course, and I deal with this stuff regularly. I am loaded with docks, seawalls, boatlifts and more.

 

[ICE]

Leakage Current Measurement Device

Who is responsible for providing the device.

An annual test of each boat with the leakage current measurement device is a prudent step toward determining if a boat has defective wiring that may be contributing hazardous voltage and current.

There is no schedule outlined in the code other than a suggestion of once a year. I don't know what's involved to perform a test but monthly seems like a haphazard approach.

How do you deal with it?

Is there an explanation for the 30 &100ma ratings that protect equipment but not people? Is 3 to 5ma not doable/

 

[jar546]

Here is some interesting information on electric shock and NEC 555.

ESD & FAQ

WHAT IS ELECTRIC SHOCK DROWNING? Electric Shock Drowning (ESD) is the result of the passage of a typically low level AC current through the body with sufficient force to cause skeletal...

www.electricshockdrowning.org

 

[jar546]

Who is responsible for providing the device.

The permit holder

There is no schedule outlined in the code other than a suggestion of once a year. I don't know what's involved to perform a test but monthly seems like a haphazard approach.

How do you deal with it?

Is there an explanation for the 30 &100ma ratings that protect equipment but not people? Is 3 to 5ma not doable/

We don't do annual inspections, just make sure that new systems that are installed meet NEC 555.

There are new products on the market and more in the works to help with compliance. We have entire marina substations that have been installed and simple products like this https://marinaee.com/marina-power-l...-equipment/marina-ground-fault-control-panel/

 

[jar546]

Here is some summarized information from a previous class on this subject prior to the 2023 NEC.

Introduction to Marina Electrical Systems

This session reviewed the current ground-fault requirements per the National Electrical Code (NEC) and general best practices for marina electrical systems. It emphasized early detection and immediate addressing of electrical problems to minimize or avoid issues within a marina.

Course Description

The session focused on several critical aspects of marina electrical systems:

1. Receptacle Selection:
   • For sailboats, houseboats, and fishing boats, different receptacles are recommended.
   • Voltage ratings:
     • 20 amp and 30 amp receptacles are typically 120V and must be GFCI protected.
     • 50 amp receptacles are usually 120/240V.
     • 100 amp or 200 amp, 4-wire receptacles are 120/240V or 480V.
     • 100 amp or 200 amp, 5-wire receptacles are 120/208V or 277/480V.
   • 100 amp receptacles are IEC Pin & Sleeve configuration, 30 amp and 50 amp receptacles are twist-lock, while most 20 amp receptacles are straight blade GFCIs.
2. Avoiding Adapters:
   • Most “Y-Adapter” cord sets are not listed products and do not provide the proper circuit protection for safe electrical connections.
3. Electric Shock Drowning (ESD):
   • ESD occurs when faulty wiring energizes underwater metals, creating an electrical field.
   • Swimmers entering this field complete the circuit to ground, leading to varying degrees of electric shock.
   • Fresh water poses a higher risk since it is more resistive than salt water, making electric current leakage a major concern.

Electrical Safety and Maintenance

1. In-Water Hazards and ESD:
   • ESD is caused by energized underwater metals such as boat props, dock frames, and ladders.
   • The human body, being a better conductor than fresh water, becomes the path of least resistance for electrical currents.
   • Current effects can range from a slight tingle to complete loss of muscle control, and in severe cases, ventricular fibrillation.
2. Inspection Requirements:
   • Annual inspections, testing, and maintenance of electrical wiring and equipment in marinas are essential.
   • This includes all electrical wiring, ground connections, conduits, supports, pedestals, utility centers, distribution gear, receptacles, and circuit breakers.
   • Proper documentation of these inspections is crucial for compliance and liability purposes.
3. Testing Procedures:
   • Typical testing involves:
     1. Turning off all breakers on the power pedestal and testing device.
     2. Turning off all circuits on the vessel.
     3. Plugging the power cord or cords into the testing device and then into the pedestal.
     4. Energizing the power outlet supply and then the testing device.
     5. Energizing the VGFCU (main and branch breakers).
     6. Energizing all circuits on the vessel one at a time and documenting the ground-fault reading.
   • Vessels must have ground-fault readings not exceeding 30mA to be code-compliant. Vessels exceeding this threshold require repairs and retesting.

General Electrical Safety Rules

1. Prohibiting Swimming:
   • Swimming in marinas should be strictly prohibited, with clear signage indicating the potential shock hazards.
2. Certified Electricians:
   • All electrical work should be conducted by certified electricians.
   • Boat owners should ensure their electrical work is performed by ABYC certified professionals and should document all inspections and maintenance activities for liability purposes.
3. Routine Inspections:
   • Regular inspections and maintenance should be performed at least annually, adhering to NFPA 5.20 "Maintenance of Electrical Wiring and Equipment."
   • Documenting these activities is essential for compliance and liability management.

Technical Details on Ground-Fault Protectio

1. NEC 555.35 - Ground-Fault Protection:
   • Receptacles: Must be ground-fault protected at 30mA or less.
   • Feeders and Branch Circuits: Must be ground-fault protected at 100mA or less.
2. NEC 555.24 - Required Signage:
   • Permanent safety signs must be installed to notify users of electrical shock hazards.
   • Signs should be visible from all approaches to the marina or boatyard facility and state, “WARNING – POTENTIAL SHOCK HAZARD – ELECTRICAL CURRENTS MAY BE PRESENT IN WATER.”
3. Inspection and Testing Compliance:
   • Inspections should cover all electrical components in the marina, including boats connected to shore power.
   • Testing for ground faults should be conducted upon the initial connection to the marina electrical system and annually thereafter. Boats must display leakage under 30mA to be compliant.