Boat dock bonding 2020

[hillbilly1]

I was reading over 555.13 in the 2020 code, and new verbiage was added “using solid copper conductors; insulated, covered, or bare…….” It appears to prohibit stranded. This would be incredibly stupid to use on a hinged gangway to a floating dock where flexibility is required. Another slip up of the NEC?

 

[synchro]

I was reading over 555.13 in the 2020 code, and new verbiage was added “using solid copper conductors; insulated, covered, or bare…….” It appears to prohibit stranded. This would be incredibly stupid to use on a hinged gangway to a floating dock where flexibility is required. Another slip up of the NEC?

Perhaps that means no copper-clad aluminum wire?

 

[hillbilly1]

Perhaps that means no copper-clad aluminum wire?

Maybe……

 

[Little Bill]

Hard to find covered/insulated solid conductors over #10. So I'm thinking they just mean "pure" copper, not coated, as Synchro said.

 

[retirede]

If it simply said “copper conductor”, would anyone here really think that allowed copper-clad aluminum? I wouldn’t.

Applying Charlie’s Rule, “solid”, means “solid”. Having said that, I don’t see where “solid” or “conductor-solid” is defined in article 100.

I agree with Hillbilly - they messed this up.

 

[don_resqcapt19]

This is typical of the requirement for bonding conductors in Article 680. The reason for requiring a solid conductor is for corrosion resistance.

The rule only applied to floating buildings in the 2017 code and did not include the requirement that the bonding conductor be solid.

Article 553 for Floating Buildings was merged into 555 for the 2020 code and the bonding rule placed in Part I so it applies to both floating buildings and marinas. I did not find the PI or FR that made the actual language change to require a solid conductor.

I can understand the concern for the use of solid and possible breakage of the conductor from movement. Probably could use a PI to fix this for the 2026 code.

 

[RCS Rick]

Here is a further question regarding 555.13. I am in discussion with AHJ regarding: "shall be connected to the grounding buss in the panelboard". Does this mean the main panelboard at the house or could it be the sub panel at the dock?

 

[Dennis Alwon]

Here is a further question regarding 555.13. I am in discussion with AHJ regarding: "shall be connected to the grounding buss in the panelboard". Does this mean the main panelboard at the house or could it be the sub panel at the dock?

Imo, it means the panel at the dock. If it meant the service panel then I believe it would have stated that.

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 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.

 

[Barney B]

IMO the panel was trying to avoid the extra resistance created in corroded terminations on stranded wire as compared to solid wire in what may be a corrosive environment. Each strand in a stranded conductor tends to corrode individually rather than just around the perimeter of the wire. This is the reasoning behind requirements for solid copper bonding jumpers in Article 680.

 

[wwhitney]

If solid copper is required, but you want stranded for flexibility, nothing prevents running two in parallel, one solid, one stranded. Then you can see which one fails first, the solid one from mechanical forces, or the stranded one from corrosion.

Cheers, Wayne