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Aluminum wire?

iwannam3

Member
Aug 8, 2016
949
1,322
Washington
I have a circuit that is no longer used and has a 60 amp fuse with 4ga aluminum wire in a 3/4 inch metal conduit running to where I could install a HPWC. Looking at the FAQs in installation manual it says Copper feed only. Is that true, the internal connectors are not AL/CU rated? The model 3 is rated at 40 amps. If I have to replace the AL wire, can I use 6ga in a 3/4 inch conduit, the Tesla manual says the HPWC has 1 inch conduit entrances, can I just use a bushing or is there a code requirement for 1 inch?

Thanks
 

BerTX

Supporting Member
Supporting Member
May 2, 2014
3,505
3,568
Texas/Washington
I have a circuit that is no longer used and has a 60 amp fuse with 4ga aluminum wire in a 3/4 inch metal conduit running to where I could install a HPWC. Looking at the FAQs in installation manual it says Copper feed only. Is that true, the internal connectors are not AL/CU rated? The model 3 is rated at 40 amps. If I have to replace the AL wire, can I use 6ga in a 3/4 inch conduit, the Tesla manual says the HPWC has 1 inch conduit entrances, can I just use a bushing or is there a code requirement for 1 inch?

Thanks
Not an electrician, so just suggestions to explore...

You could put a junction box and use approved Al/Cu connectors to add a copper run to the TWC inside a flexible conduit connector.

If the breaker is not in the place where the TWC will be located, you will likely need a disconnect in that room. Use that device as the junction between the Al and the Cu pigtail connecting to the TWC.
 

iluvmacs

Member
Jan 27, 2014
489
810
Madison, WI
Above reply has best suggestions (unless you just replace the wire). Using a 60A disconnect box (most have Al/Cu rated lugs) will be WAY cheaper than using Al/Cu rated splices for this gauge. Don't forget the Al wire anti-oxidizer goop in any case...

I just installed an HPWC with 3/4" conduit fittings. You have to drill the hole anyway, so make it whatever size is appropriate. Really the manual should say "up to 1 inch".
 
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iwannam3

Member
Aug 8, 2016
949
1,322
Washington
Not an electrician, so just suggestions to explore...

You could put a junction box and use approved Al/Cu connectors to add a copper run to the TWC inside a flexible conduit connector.

If the breaker is not in the place where the TWC will be located, you will likely need a disconnect in that room. Use that device as the junction between the Al and the Cu pigtail connecting to the TWC.
Excellent idea, but the Al wire was packed way too tight to meet code and I needed to shorten the conduit to mount the HPWC and did not have a way to cut the conduit and spare the wire. I'm sure electricians have something like a copper tubing cutter that can cut conduit with wire inside. Ran two 6 ga and a 10ga ground.
 
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Lloyd

Well-Known Member
Supporting Member
Jan 12, 2011
6,321
2,123
San Luis Obispo, CA
With aluminum wire, you should also re-torque all of your lugs and connections every couple of years as it tends to shrink away from the lug over time.
 
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Lloyd

Well-Known Member
Supporting Member
Jan 12, 2011
6,321
2,123
San Luis Obispo, CA
You could splice copper pigtails on the aluminum. There are kits available for this procedure. All the houses in my neighborhood were wired with aluminum, and it's noted in inspection reports when they go on sale. Some people go through their houses and pigtail all the junction boxes. Others just use aluminum-compatible switches and stuff.

AlumiConn 2-Port Al/Cu Wire Connector (25-Pack)-95025 - The Home Depot

This is a patch for a failed AL connection. It does not really fix the problem.
 

iluvmacs

Member
Jan 27, 2014
489
810
Madison, WI
You could splice copper pigtails on the aluminum. There are kits available for this procedure. All the houses in my neighborhood were wired with aluminum, and it's noted in inspection reports when they go on sale. Some people go through their houses and pigtail all the junction boxes. Others just use aluminum-compatible switches and stuff.

AlumiConn 2-Port Al/Cu Wire Connector (25-Pack)-95025 - The Home Depot
You'll note that those do not come close to handling 4 AWG wire. You have to instead use something like Polaris 4-14 AWG Bagged Insulated Tap Connector, Black-IT-4B - The Home Depot which is rather expensive (hence the suggestion to use a disconnect box with lugs as a much more cost effective solution)
 
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