Dissimailar metal contact

Status
Not open for further replies.
B

brian_mller

Member
Location
austin, tx
I batting 1 for 1 today.....here is another one I am tusseling with the builder:

the stranded aluminum conductor is bundled with the equipment grounds. I say no. Builder says okay. Thoughts on this one?
 

Attachments

  • IMG aaa.jpg
    IMG aaa.jpg
    20.9 KB · Views: 2
It shouldn't have been done that way, but most likely not a big deal if they aren't completely separated. We solar guys install bare copper ground next to aluminum racking all the time and as long as the solid connections are done with the right material then it doesn't cause problems if there's a little bit of incidental contact. And that is exposed to the elements where corrosion will happen much faster.

I would probably ask to cut the cable ties that are easily accessible and install new ones just around the copper, but not demand that all contact be eliminated.

A key point is that these are not supposed to have current flowing through them.
 
Why is the builder saying what's okay. I happen to agree with him on this but he should not be calling the shots. Aluminum and copper cannot be connected together without special terminations, however, I know of nothing that prevents copper from being in contact with aluminum
 
Dennis Alwon said:
Why is the builder saying what's okay. I happen to agree with him on this but he should not be calling the shots. Aluminum and copper cannot be connected together without special terminations, however, I know of nothing that prevents copper from being in contact with aluminum
Click to expand...

I agree, occasional contact shouldn't be a problem.
 
GoldDigger said:
Incidental contact in a corrosive atmosphere, or even wet with some salt content can cause galvanic corrosion even above ground and outside raceways.
Arizona probably fine. Florida probably a bad idea.
Click to expand...

If the atmosphere is corrosive or the location is a damp location then could you be using the equipment in the photo in the OP?
 
infinity said:
If the atmosphere is corrosive or the location is a damp location then could you be using the equipment in the photo in the OP?
Click to expand...

I don't know why not. 30 yards from the ocean is not a classified location or anything, but electrical equipment there will need to be replaced sooner than elsewhere.
 
Dennis Alwon said:
Why is the builder saying what's okay. I happen to agree with him on this but he should not be calling the shots.
Click to expand...

The OP appears to be an engineering consultant. If the job passed inspection (whick it probably did) and there is nothing in the job specs to prevent the AL & CU being in contact I can see where the builder would balk at making any changes. The EC is not going to make changes for free unless they are in the wrong in some way (code or job specs).
 
I have been making and removing or working on connections for a forty years now, and have yet to see any real incident of galvanic action inside connections. I've seen lots of connection failures. They are easily figured out to be from loose connections when checked carefully , or corrosion on the terminal itself. Lots of corrosion on the terminal incidents. Zero due to actual aluminum mixed with copper though. Zero.
 
infinity said:
I agree, occasional contact shouldn't be a problem.
Click to expand...

We do it all the time.
Aluminum cable ladder with bare copper ground running through it.
Of course it isn't touching the whole way. We stand it off with clamps about every 4 feet or so.
Poco substation control houses. That's what they want.
 
Status
Not open for further replies.
Top