555.14 Equipotential Planes and Bonding of Equipotential Planes.

The equipotential plane must encompass the area around the equipment and must extend from the area directly below the equipment out at least 36 inches in all directions from where a person can stand and make contact with the equipment.
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The equipotential plane must encompass the area around the equipment and must extend from the area directly below the equipment out at least 36 inches in all directions from where a person can stand and make contact with the equipment.

Code Change Summary: New code Section 555.14 requires an equipotential plane for specific electrical equipment.

In the 2023 NEC®, a public input (code change proposal) was accepted to create new code Section 555.14 based on similar language existing in 682.33 which covers equipotential planes and bonding of equipotential planes for electrical equipment adjacent to natural and artificially made bodies of water. The new code section is intended to mitigate step and touch voltages for electrical equipment supplying power to equipment located at or on docks or floating buildings.

The new language in 555.14 requires an Equipotential Plane to be installed adjacent to all outdoor service equipment or any disconnecting means that controls equipment in or on the water where the following conditions are present:

(1) Where the system voltage exceeds 250 volts to ground

(2) Where the equipment is located within 10 feet of the body of water

An Equipotential Plane is defined in Article 100 as “conductive elements that are connected together to minimize voltage differences”.

Creating the equipotential plane required in 555.14 includes bonding all metallic enclosures and controls that are likely to become energized and are accessible to personnel with a solid copper conductor; insulated, covered, or bare; not smaller than 8 AWG. The equipotential plane must encompass the area around the equipment and must extend from the area directly below the equipment out at least 36 inches in all directions from where a person can stand and make contact with the equipment.

According to the definition in Article 100, “likely to become energized includes conductive materials that could become energized because of a failure of electrical insulation or electrical spacing.

Note that an equipotential plane is not required for the controlled utilization equipment on the docking facility or floating building supplied by the service equipment or disconnecting means.

Below is a preview of the NEC®. See the actual NEC® text at NFPA.ORG for the complete code section. Once there, click on their link to free access to the 2023 NEC® edition of NFPA 70.

2020 Code Language:

This code section did not exist.

2023 Code Language:

N 555.14 Equipotential Planes and Bonding of Equipotential Planes. An equipotential plane shall be installed where required in this section to mitigate step and touch voltages at electrical equipment. The parts specified in this section shall be bonded together and to the electrical grounding system. The bonding conductor shall be solid copper conductors; insulated, covered, or bare; not smaller than 8 AWG.

(A) Areas Requiring Equipotential Planes.

Equipotential planes shall be installed adjacent to all outdoor service equipment or disconnecting means that control equipment in or on water where the following conditions exist:

(1) Where the system voltage exceeds 250 volts to ground

(2) Where the equipment is located within 10 feet of the body of water

The equipotential plane shall include all metallic enclosures and controls that are likely to become energized and are accessible to personnel. The equipotential plane shall encompass the area around the equipment and shall extend from the area directly below the equipment out not less than 36 inches in all directions from which a person would be able to stand and come in contact with the equipment.

(B) Areas Not Requiring Equipotential Planes. Equipotential planes shall not be required for the controlled utilization equipment on the docking facility or floating building supplied by the service equipment or disconnecting means.

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555.14 Equipotential Planes and Bonding of Equipotential Planes.

Below is a Real Question from our Electrical Continuing Education Courses for Electrical License Renewal:

Which of the following is true for equipotential planes covered in 555.14?

A: The bonding wire must be a solid copper conductor; insulated, covered, or bare; not smaller than 8 AWG.
B: The bonding wire must be a solid aluminum conductor.
C: The bonding wire must be stranded.
D: The bonding wire must be uninsulated.
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