Seeking Opinion on Bonding of Dock Ladders

[jar546]

I received this email sent to a bunch of us from one of our peers:

Good Evening Colleagues,

I’m reaching out to gather your perspectives on how your organizations handle metal ladders installed on docks that have any source of electrical power (shore power pedestals, boat lifts, lighting, receptacles, etc.). There’s been some suggestion that my jurisdiction is alone in enforcing this aspect of the NEC; I’d like to compare practices, code interpretations, and rationale across jurisdictions and trades.

• NFPA 70 (NEC) Article 555.13: “All non–current-carrying metal parts that are likely to become energized shall be connected to the branch circuit or feeder equipment grounding conductor by a bonding conductor that is insulated, covered, or bare and is not required to be larger than 8 AWG copper.”

There is an assumption that because a ladder is on a wood dock that there is no issue with the metal ladder and bonding isn’t required. The hazard isn’t with the wood dock, it’s stray current in the water from a faulted boat or dock circuit. A metal ladder in contact with that water can become energized and present a shock hazard (electric-shock drowning risk). Bonding provides a low-impedance path back to the source so protective devices can operate.

This is the other side of the argument.
Do you require bonding of metal ladders at any dock with electrical service? If not, what is your code basis and safety analysis?
Thank you in advance for weighing in. Our shared goal is to reduce electric-shock risk at docks through clear, consistent application of NEC 555.
Regards,

 

[jar546]

This was my response. Do you agree or disagree? What are your thoughts?

The current verbiage is similar to the understood section concerning bonding of gas lines, which means, if it does not have electric going to it, it is not required to be bonded. In other words, it is only likely to be energized if it is connected to electricity, such as a furnace. Then, the electric that supplies the gas appliance has a ground and it is bonded. Yes, I know this is not about gas piping, but hear me out.

However, 555 is similar to pool bonding and the intent was clarified in the 2023 NEC for 555.13 which now reads:

555.13 Bonding of Non-Current-Carrying Metal Parts.
All metal parts in contact with the water, all metal piping, and all non-current-carrying metal parts that are likely to become energized and that are not connected to a branch circuit or feeder equipment grounding conductor, shall be connected to the grounding bus in the panelboard using solid copper conductors; insulated, covered, or bare; not smaller than 8 AWG. Connections to bonded parts shall be made in accordance with 250.8.

This solidifies the intent that these metal parts are supposed to be bonded. I understand we are not under the 2023 NEC yet, but this is a clarification of the intent. This is my opinion, and how it is handled in my two jurisdictions.