THHN vs XHHW Aluminum?

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tx2step

Senior Member
I'll be installing a new 120/240 single phase 400A service using 2 parallel sets of 3 each #250 Aluminum in 2" IMC. I think I can get the Aluminum in either THHN or XHHW. I haven't used any XHHW in a long time. I seem to remember that the XHHW insulation was more difficult to strip? I also seem to remember that the XHHW insulation was more prone to tearing?
1. What are the pro's and con's of using XHHW instead of THHN?
2. Is the aluminum usually a "compact conductor" with both insulation types?
3. I haven't used aluminum in a while -- other than using penetrox & torquing the lugs, is there anything else I should do to make sure I have trouble free mechanical terminations? Is it still recommended to brush the wire with a stainless steel brush before applying penetrox?
4. Any suggestions on how to do this the best, easiest & most cost effective way?

Thanks in advance
 

Strife

Senior Member
I don't think they even make (sell more likely) Thhn AL.
I know XHHW is a compact conductor, not sure about Thhn.
Did quite a few jobs in XHHW lately, the conductor is very compacted (basically a 600 Xhhw is almost as small as a 400 Cu), but it's still lighter and easier to bend than Cu. Last year we pulled 200 some feet of 250 Xhhw Al with 3 people, by hand.
Not sure if it's harder to strip because is Xhhw or because the "soap free" insulation. Seems to me that, while it's true that you don't need soap on Southwire lube free wire, they are difficult to strip.

I'll be installing a new 120/240 single phase 400A service using 2 parallel sets of 3 each #250 Aluminum in 2" IMC. I think I can get the Aluminum in either THHN or XHHW. I haven't used any XHHW in a long time. I seem to remember that the XHHW insulation was more difficult to strip? I also seem to remember that the XHHW insulation was more prone to tearing?
1. What are the pro's and con's of using XHHW instead of THHN?
2. Is the aluminum usually a "compact conductor" with both insulation types?
3. I haven't used aluminum in a while -- other than using penetrox & torquing the lugs, is there anything else I should do to make sure I have trouble free mechanical terminations? Is it still recommended to brush the wire with a stainless steel brush before applying penetrox?
4. Any suggestions on how to do this the best, easiest & most cost effective way?

Thanks in advance
 
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