Bonding Screws through Metal wall - Rust prevention and treatment options?

[archjeb]

Hi Folks,

I know bonding has be talked about in this forum ad nauseam.

I'm replacing my old AGP that I installed several years back with a Resin pool. Old pool was easy peasy, all metal, 4 points around the pool with lugs on the uprights. All standard bonding -- easy stuff.

New pool is Resin rails (bottom and top), Resin bottom and top plate. The only metal is the wall and the uprights. So standard is to use the tie bar on the wall seam to mount a ground lug. Going to do that. But some municipalities want 4 points because they want to argue NEC code interpretation. At any rate, I'm not opposed to adding more bonding points, as its not going to hurt anyway.

I'm thinking since I have the old 8ga wire loop around the pool with 4 connection points -- to go ahead and drill a hole down below the cove during new pool install and put a lug on the outside of the pool wall.

Question, what have you used successfully to treat the hole drilled through the wall? Cold Galvanized paint? Anti corrosion spray (like marine anti-corrosion spray)?

I was thinking I might go two layers...once the bolt is screwed in with lug on the outside of the wall (again below the cove) and confirm good continuity with the wall, I'd then spray with cold galvanized paint. Let that dry...then spray with marine grade anti-corrosion spray.

Something like this https://www.amazon.com/CRC-06026-Heavy-Corrosion-Inhibitor/dp/B0000AXYA0
I've used this for Marine applications and its been pretty good in Salt water.

Or have you found a better option when treating this?

 

[Texas Splash]

Good morning Arch. Have you already completed your bond modification/pool install, or are you still looking for some replies? If so, we'll beat the bushes here and try to get some experts to chime in.

 

[archjeb]

thanks for the follow up and pinging me on this thread.

No I haven't yet. Ended up getting sick this week...so laying low till recovery.

Honestly, I'm having second thoughts and thinking I'll just bond at the stainless service wall seam with the #8 copper wire loop in place and call it good. If its good enough for latest NEC code, its good enough for me.

The more I think about drilling into the wall, it brings its own set of issues with potential rust and warranty. Just not worth it. Electrically, the bond at the wall seam is best, especially with a partial backfill, so I can at least visually see that bond connection since that service wall section will have access (not back-filling in that section). All other areas that get partially back-filled to the wall, will never get looked at, unless there is a problem.

 

[phonedave]

If you do drill a hole, use a good sharp drill, and file and deburr the edges of the hole. Any sharp point on the edge becomes a stress riser. A hole is bad enough, a hole with a nick in the perimeter is a disaster waiting to happen in a structure under a large tensile load, such as the wall of an ABG.

 

[archjeb]

If you do drill a hole, use a good sharp drill, and file and deburr the edges of the hole. Any sharp point on the edge becomes a stress riser. A hole is bad enough, a hole with a nick in the perimeter is a disaster waiting to happen in a structure under a large tensile load, such as the wall of an ABG.

Thanks for the reminder. In the end, I think its the course of wisdom to just bond on one of the existing screws on the wall seam. Maybe two of the screws if I want some extra insurance.