existing pool with aluminum equipotential grounding conductors

[malachi constant]

We're doing the engineering on an existing indoor pool where the deck is getting replaced. We expect the existing "perimeter surfaces bonding conductor" to be buried bare in the mudding just below the tile, and so are putting in our documents that the contractor shall replace this.

We wondered if while we're touching that, maybe an inspector will require us to bring more of the pool grounding system up to code, so took a look at the existing 1970s-era documents to see what they probably have installed. We found a pool grounding detail with a note that reads, "Grounding conductor this area must be aluminum, copper is not permitted due to possible reaction between the aluminum pool shell and the copper." This is at odds with what the NEC allows - 680.26(B) states copper shall bond parts together.

Any thoughts on how to handle this? My inclination is to simply replace the aluminum that is likely to get nicked with copper, and join them with rated splices. We would also call out for the contractor to both visually inspect and test the grounding system. However if there is a serious issue with copper being in the vicinity of an aluminum pool shell we would need to rethink that, probably get the inspector involved sooner than we typically would.

Thanks!

 

[Dennis Alwon]

Aluminum cannot be buried in the dirt

 

[Dennis Alwon]

Article 680.26 will not allow aluminum as an epb

 

[GoldDigger]

The real problem that needs to be solved is connecting the copper wire to the aluminum shell. Just having the two in the same area will not by itself cause a problem.
Basically the attachment between the pool shell and the EPB needs to be made of a suitable metal, such as some types of stainless steel, which will not react badly with either the copper or the aluminum. That NEC is fine with that type of solution, but you may need to find a connector/lug that is listed for that application, especially if the inspector is having a bad day.

A typical (Polaris connector or Al/Cu wirenut) solution for bonding Al wire to Cu wire will not be suitable for unprotected direct burial or ground contact.

 

[Dennis Alwon]

Certainly the pool companies have a lug that is listed for this purpose. I am certain that many of the lug manufacturers have lugs rated for direct burial that can attach to a an aluminum pool shell

 

[malachi constant]

Thanks all! (Or both of you, I should say.)