Aluminum pool coping bonding

[ozark01]

I am wiring some polymer wall pools with aluminum coping. The AHJ is requiring me bond each section of coping since they are not tied together mechanically. The problem is that they are requiring a lug rated for direct burial that is also rated for direct contact with aluminum and for a #8 copper wire. I can not find this type of lug. Does anyone have any ideas how I can bond this coping so it will satisfy the inspector? They have offered no suggestions....only the requirements stated above.

 

[infinity]

I agree with the inspector that the bonding is required. I would contact the people who make the coping and ask them how you're supposed to bond their product. I would think that an AL/Cu lug would satisfy the two different metals but the direct burial may be a problem.

 

[ozark01]

Thanks for the response. The pool builder did contact the coping supplier and they had no solution. You are correct that the problem is finding a direct burial lug rated for CU/AL.

 

[Dennis Alwon]

Thanks for the response. The pool builder did contact the coping supplier and they had no solution. You are correct that the problem is finding a direct burial lug rated for CU/AL.

It amazes me that a company can put out a product but has no remedy for the legal installation. I would make them figure it out or pull the pool out of the ground.

The world is full of idiots and I happen to be one of them.....:grin:

 

[LarryFine]

The world is full of idiots and I happen to be one of them.....:grin:

That recognition disqualifies you. :smile:

 

[Dennis Alwon]

That recognition disqualifies you. :smile:

Are you sure???

 

[petersonra]

It amazes me that a company can put out a product but has no remedy for the legal installation. I would make them figure it out or pull the pool out of the ground.

any reason you can't just drill and tap with a SS machine screw?

 

[Dennis Alwon]

any reason you can't just drill and tap with a SS machine screw?

And what type of lug would you use underground that is suitable to be in contact with the aluminum. The screw may be fine but the lug that is touching the aluminum must be rated for that and be underground approved also.

 

[tkb]

Couldn't you use a stainless steel nut and bolt with a stainless washer in between the aluminum and the the CU DB lug?

I known it may not be "UL" but it keeps the disimilar metals from making contact and the lug can be buried.

 

[Dennis Alwon]

Couldn't you use a stainless steel nut and bolt with a stainless washer in between the aluminum and the the CU DB lug?

I known it may not be "UL" but it keeps the disimilar metals from making contact and the lug can be buried.

That sounds feasible but I guess you may have to sell that idea to the inspector. The idea of aluminum in the ground sounds like a bad idea to me. Aluminum supports for the pool buried in the ground????? What happens when that corrodes--

I thought aluminum and underground was a bad mix.

 

[petersonra]

Couldn't you use a stainless steel nut and bolt with a stainless washer in between the aluminum and the the CU DB lug?

I known it may not be "UL" but it keeps the disimilar metals from making contact and the lug can be buried.

Thats kind of what I had in mind. I don't see a UL problem. I doubt the listing prohibits this kind of install.

 

[petersonra]

That sounds feasible but I guess you may have to sell that idea to the inspector. The idea of aluminum in the ground sounds like a bad idea to me. Aluminum supports for the pool buried in the ground????? What happens when that corrodes--

I thought aluminum and underground was a bad mix.

I don't see an issue with it. When aluminum corrodes it forms an oxide layer that is very corrosion resistant. The oxide is not a good conductor. But you are not trying to conduct anything here, just make an equipotential grid.

 

[kbsparky]

I thought that those lugs and the corresponding jumper wires ended up embedded in poured concrete, not exactly the same thing as "buried" in the ground? :-?

We simply use standard Cu/AL lugs, fastened with SS bolts and "K" nuts directly to the coping flange.

Never had a problem with this method, nor with any inspector-critter who certified our work. :grin:

 

[don_resqcapt19]

I don't see an issue with it. When aluminum corrodes it forms an oxide layer that is very corrosion resistant.

If there isn't a problem why does the code have section 250.64(A)? Aluminum in contact with the earth has a short life.
Don

 

[petersonra]

(A) Aluminum or Copper-Clad Aluminum Conductors.
Bare aluminum or copper-clad aluminum grounding conductors
shall not be used where in direct contact with masonry
or the earth or where subject to corrosive conditions.
Where used outside, aluminum or copper-clad aluminum
grounding conductors shall not be terminated within 450 mm
(18 in.) of the earth.

this refers to conductors, not metal parts you are bonding. as long as he is not planning to use aluminum conductors it does not apply, and would only apply if he were using uninsulated aluminum conductors.

 

[Dennis Alwon]

this refers to conductors, not metal parts you are bonding. as long as he is not planning to use aluminum conductors it does not apply, and would only apply if he were using uninsulated aluminum conductors.

I guess I still don't get it. My point was that why will an aluminum post last underground-- nothing to do with boding--- I have seen aluminum wire wear out in weaks under certain soil conditions. Would these post not deteriorate????

 

[kbsparky]

I guess I still don't get it. My point was that why will an aluminum post last underground-- nothing to do with boding--- I have seen aluminum wire wear out in weaks under certain soil conditions. Would these post not deteriorate????

Nope. You are not dealing with raw aluminum here, but an aluminum alloy which is a different animal. It has to be able to withstand the corrosion effects of the chlorine and other chemicals in the water. Same thing with the CU/AL lugs used. Compatible for use on both copper and aluminum conductors.