I have a 230' long run from a main panel to a workshop subpanel. The panel will be 240v/125a. The engineer is calling for 3/0 aluminum due to voltage drop. There is NO WAY to get a 3/0 aluminum wire under any lug that will fit in a Siemans 200 amp panel. If I switch to copper, I can run 1/0 for the 2 energized lines then run aluminum for the neutral and bond. The cost of the 1/0 copper is substantially more than the 3/0 aluminum, but it will save headaches in the future. I cannot find anything that says I can't do this. These will be separate feeders in an underground sch 40 pvc pipe. Any input?
Mixing copper and aluminum wires as sub feeders
- Thread starter jrl5687
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- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
You mean the lugs on the 125 amp panel will not handle 3/0. They make connectors that are a pin to reduce the 3/0 so it fits. Something like this which is a compression fitting
- Location
- New Jersey
- Occupation
- Journeyman Electrician
Are you saying that a 125 amp panel won't accept a #3/0?
letgomywago
Senior Member
- Location
- Washington state and Oregon coast
- Occupation
- residential electrician
Even a cheap splice reducer to change to copper before the breaker would be compliant. Or if you have a crimper crimp reducers.
The lugs on the 125 will, but the 200 I'm coming from needs a 125a breaker or a sub-feed lug kit. The lug kit will not accept 3/0. It says 2/0 max. I've never used a pin adapter.
Thank you, I'm going to look into these.
letgomywago
Senior Member
- Location
- Washington state and Oregon coast
- Occupation
- residential electrician
6 inches of 1/0 copper and a splice reducer boom done.
Thank you, thats a great idea. Hadn't thought of that.
Great idea, thanks.
letgomywago
Senior Member
- Location
- Washington state and Oregon coast
- Occupation
- residential electrician
Trying to stay in a budget use the 10 dollar splice instead of the 50 dollar pins. The cool thing about the pins is they make 90° ones
- Location
- New Jersey
- Occupation
- Journeyman Electrician
Got it. Dirty little secret, breaker terminals rated for #2/0 copper will often allow a #3/0 compact strand alumiunum to fit. Not code complaint due to the listing but it should be.
letgomywago
Senior Member
- Location
- Washington state and Oregon coast
- Occupation
- residential electrician
That's like you can get 10s into a lug for 8s minimum by folding into a uGot it. Dirty little secret, breaker terminals rated for #2/0 copper will often allow a #3/0 compact strand alumiunum to fit. Not code complaint due to the listing but it should be.
winnie
Senior Member
- Location
- Springfield, MA, USA
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- Electric motor research
IMHO the reduction connections already proposed are the proper solution to the problem.
However to answer the original question: Yes, a circuit can be run with a combination of Aluminium and Copper conductors. You could have hot A made with Cu, neutral and hot B made with Al, and the ground could be steel conduit.
The only restriction in code on mixing conductors is for parallel conductors, where set of paralleled conductors must be the made of conductors of the same characteristics.
-Jon
However to answer the original question: Yes, a circuit can be run with a combination of Aluminium and Copper conductors. You could have hot A made with Cu, neutral and hot B made with Al, and the ground could be steel conduit.
The only restriction in code on mixing conductors is for parallel conductors, where set of paralleled conductors must be the made of conductors of the same characteristics.
-Jon
- Location
- New Jersey
- Occupation
- Journeyman Electrician
Not exactly the same thing but okay.
electrofelon
Senior Member
- Location
- Cherry Valley NY, Seattle, WA
I was going to say the same thing. I have and would do that in a heartbeat.Got it. Dirty little secret, breaker terminals rated for #2/0 copper will often allow a #3/0 compact strand alumiunum to fit. Not code complaint due to the listing but it should be.
Not sure if you have to follow the engineers design exactly in this case, but he doesn't know what he is talking about, 2/0 AL is fine for that run. Plus 3/0 might be hard to find.
electrofelon
Senior Member
- Location
- Cherry Valley NY, Seattle, WA
No that is very different (but still actually fine in reality). Most crimp on lugs I use specifically say you can use one size up max AL size from the max copper size.
- Location
- Illinois
- Occupation
- retired electrician
Those are not suitable for use with panelboard and breaker terminations as they are only listed for the termination of Class B or C stranded conductors. If you want to do that, you need this type, but rated for aluminum conductors.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
I didn't check all the info but I wanted to give the op an idea of what could work.... He would have to check the info of the item he seeks.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
Ilsco makes all sorts of combinations for regular and fine stranded conductors. These are good for #3/0 Al and feature a #1/0 pin.
wwhitney
Senior Member
- Location
- Berkeley, CA
- Occupation
- Retired
Solid pin? I think the point Don was making is that the lug on the panelboard or breaker may only be rated for stranded conductors, not for a solid pin.
Cheers, Wayne
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