Has anyone used Aluminum electrical wire for their charging outlet? I live in a mixed-use building (condo with commercial on first floor), so use of Aluminum is permitted. A neighbor told me the cost of aluminum conduit is about 25% that of copper for an equal current rating. I'm aware of the problems in the 60s and 70s related to aluminum wiring (not accounting for different coefficient of expansion than copper and galvanic corrosion at the termination.) As those problems have been addressed, any reason not to use it?
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Unless you are running a really long way, #8 (or #6) Cu isn't all that expensive. I would rather spend the little bit more on Cu than to try do deal with the thicker and stiffer Al. #8 Cu is already hard to deal with inside a j-box for the 14-50R.
I wouldn't doubt if some said they did, but typically I've found that for #2 or smaller, CU is really the best choice and isn't too much of a difference price-wise, all things considered (labor, materials, etc.)
You only need #6 AL for a 14-50 if you wanted to use it, so in many cases it's not bigger than what's already considered (#8 CU is sufficient for wire-in-conduit, not Romex) and it's more of a pain in the ass to deal with.
You only need #6 AL for a 14-50 if you wanted to use it, so in many cases it's not bigger than what's already considered (#8 CU is sufficient for wire-in-conduit, not Romex) and it's more of a pain in the ass to deal with.
sfriedrich
Member
CliffG
Member
Yes, and we used #4 Al - and the difference in pricing for #6 Cu was in the hundreds of bucks for the 100+ ft. wiring.
ghost640
Member
Can I ask a sort-of related noob question - what's the difference between 14-50 and 14-50R? I just went to the hardware store to buy one - my Tesla pamphlet says 14-50 but the store just had the 14-50R.
I'm not familiar with all the details of the building mechanicals, but the main electrical room is about 300 ft from my assigned parking spot in the building. There may be a closer access point and I'll have to find out details from building maintenance when the time gets closer (I have a MX rez, so it will be a while).
brucet999
Active Member
Look up ampacity tables online. Normal wire sizes called out for a given sized outlet are predicated on 100 ft of wire distance from the panel (or less) allowing no more than 5% voltage drop from line resistance. Your 300 foot run will require larger wire to reduce the line losses. Remember, you are delivering watts to the onboard charger, so even though the amperage will remain at 40, lower voltage from line losses will reduce the number of watts delivered and therefore increase the time required for a charge.
A thread from the past :smile:
I went with copper. First, the electrician said if aluminum is used, the connections need to be inspected every year, tightened, etc. Second, the HOAs insurance policy would need to be amended if aluminum was used. Bottom line, too much hassle, despite potnetial cost savings.
I went with copper. First, the electrician said if aluminum is used, the connections need to be inspected every year, tightened, etc. Second, the HOAs insurance policy would need to be amended if aluminum was used. Bottom line, too much hassle, despite potnetial cost savings.
Cyclone
Cyclonic Member ((.oO))
Cyclone
Cyclonic Member ((.oO))
Aluminum is fine to use, you can use #6 for a NEMA 14-50 (50A at the 75 deg termination). You need to make sure to use CoAl rated devices (most are at that gauge). Some people will recommend some older mechanisms to help cope (anti-oxidation paste) - and some inspectors will even require it - but today's aluminum really doesn't need it.
There are a lot of people scared about aluminum wiring, which was warranted when considering the 1970's 2000-series aluminum used in wiring (they basically took long-haul high tension cable aluminum and made solid building wire out of it). Today's 9000-series aluminum wire is much closer to the expansion/contraction rates of existing copper wire. In addition, since larger wires are stranded, you have more protection against a single strand that works loose - you really don't have to re-torque it anymore than re-torquing copper.
Now, with that said, the copper will run cooler and at that gauge the price difference isn't too much; I recommend copper (and Tesla requires its "find an electrician" program electricians to use copper), but it will be ok.
For the HPWC, you run into a problem because you have to use #1 AL for a 100A circuit and you won't be able to work that into the HPWC terminals. You're best to use aluminum and transition to #3 copper in a junction box near the HPWC with listed connectors if you have a longer run.
There are a lot of people scared about aluminum wiring, which was warranted when considering the 1970's 2000-series aluminum used in wiring (they basically took long-haul high tension cable aluminum and made solid building wire out of it). Today's 9000-series aluminum wire is much closer to the expansion/contraction rates of existing copper wire. In addition, since larger wires are stranded, you have more protection against a single strand that works loose - you really don't have to re-torque it anymore than re-torquing copper.
Now, with that said, the copper will run cooler and at that gauge the price difference isn't too much; I recommend copper (and Tesla requires its "find an electrician" program electricians to use copper), but it will be ok.
For the HPWC, you run into a problem because you have to use #1 AL for a 100A circuit and you won't be able to work that into the HPWC terminals. You're best to use aluminum and transition to #3 copper in a junction box near the HPWC with listed connectors if you have a longer run.
hanstremblay
Member
Revisiting this thread, we have a new house where builder was cheap and only used aluminum 6AWG to run from main panel to dedicated EV junction box in garage. Electrician says we can only install a NEMA 14-30 (or 10-30) outlet in this junctions box or connect a HPWC @ 32A. If folks have wired a NEMA 14-50 outlet to aluminum 6AWG wiring and had no issues I may just go that route in a DIY...
brucet999
Active Member
See linked ampacity chart https://www.usawire-cable.com/pdfs/nec ampacities.pdf
Aluminum 6AWG is rated 15 amps lower than copper. If your wire is rated for 75º C, then it would be rated for 50amps, just barely enough. If 90ºC, a comfortable 60A.
You would have to verify that the 14-50 outlet is rated CU/AL, meaning that it is ok for aluminum. You would need to be certain, also, that you torque down the terminal screws properly to assure a good connection. It would be wise, whatever outlet is connected, to check the terminals after a few months to be sure that they are still tightly connected.
How difficult would it be to pull new copper to that location? If it is all in conduit, then it might be fairly easy.
Thanks!
I'm not sure if it's all wired in conduit for the entire route, will try to find out.
I think it's probably about 50-75 foot run from the main panel to the junction box.
Electrician was super impressed by our "fancy & expensive" (his words) 400A main service panel; can't for the life of me figure out why builder used AL for the pre-wiring of an EVSE in garage, other than just pinching pennies.
If it's too difficult or costly to re-run copper, I'll be sure to get a 14-50R outlet that is CU/AL rated.
brucet999
Active Member
Please, please check the rating of the Al wire (printed on the insulation) before you connect a 14-50. If it is not one of the 75ºC or 90ºC types with ampacity rated at 50A or higher, that would be a bad idea.
Nothing wrong with Al wiring if it meets the correct specs for the job. My builder ran Al to a junction box in my garage. Electrician ran copper from the junction box to my wall charger. No issues charging at 80A.
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