Aluminum wire for Tesla wall connector

[Ipcress]

Hi all,
I'd appreciate your thoughts. I'm getting my wall connector installed soon. I live in New England, and will mount the connector on a post next to my driveway.
The electrician would like to use a 50 amp breaker, not a 60. The charge speed penalty would be from 44 mph at 60 amp, to 37 mph at 50 amp. That seems pretty close, and I don't anticipate needing top recharging speeds as my daily use is mostly around town/short trips. Should I go along with the lower amp set-up?

He also wants to use aluminum wire. He says that the wire size needed means it will cost 2x more, at least, in copper and be more difficult to route. I noticed on page 5 of the installation manual, it says “COPPER WIRE TERMINATIONS ONLY for landing in Wall Connector wirebox terminals. Conductors can be stranded or solid.” Does this mean that the wire can be aluminum, but the “terminations” copper? The connector will be mounted 6' from the house, and about 30' total from the panel.

Thanks for your comments in advance!

 

[Sophias_dad]

He can add a pigtail to the aluminum wire to make it copper before it connects to the HPWC. He's full of crap, though. The cost differential isn't anything like 2x when you add three approved pigtails, on a 30 foot line. I'd wager he wasn't going to and WON'T use pigtails unless you are watching him like a hawk.

Is there some reason he wants to use a 50 amp breaker, like he has a zillion feet of aluminum his cost is zero on?

Thirty feet of cable is NOTHING. Don't let him screw around with aluminum. You are asking about three conductors, 30' each, at either 0.50/ft or $1 a foot, so $45 or $90 dollars. Betcha it'll cost ~$20 or more for the pigtails to get from aluminum to copper. The third conductor doesn't even need to be bigger than #10 awg so your real cost differential is probably more like $10(that is, (30+$20 for aluminum) or $60 for copper, ignoring the ground line)

If its going through conduit underground(and in the house!), you could even get away with 8awg copper for a 50 amp breaker. I myself would stick with #6 and do the 60 amp, unless you have a supply-side-limit.

I'd ask for a quote/opinion from another electrician.

 

[Rocky_H]

The electrician would like to use a 50 amp breaker, not a 60. The charge speed penalty would be from 44 mph at 60 amp, to 37 mph at 50 amp. That seems pretty close, and I don't anticipate needing top recharging speeds as my daily use is mostly around town/short trips. Should I go along with the lower amp set-up?

For this part, yeah, you won't notice any difference. If the car charges in 5 hours while you're sleeping instead of 4 hours, who cares? You sleep more than that anyway.

He also wants to use aluminum wire. He says that the wire size needed means it will cost 2x more, at least, in copper and be more difficult to route. I noticed on page 5 of the installation manual, it says “COPPER WIRE TERMINATIONS ONLY for landing in Wall Connector wirebox terminals. Conductors can be stranded or solid.” Does this mean that the wire can be aluminum, but the “terminations” copper? The connector will be mounted 6' from the house, and about 30' total from the panel.

There can be conditions of really long wiring runs where the cost difference can be a really big deal and make sense to use aluminum for it, but you are correct about the instructions in the manual. It takes special lugs made to accept aluminum, and the wall connector doesn't have those, so the final connections would need to be copper wire. So that would need some extra kind of box along the way to make the switch, and it's more hassle and parts and kills most of the cost savings.

So @Sophias_dad makes the very relevant point. For a measly 30 foot run, there is no sense in doing the extra B.S. of trying to use aluminum for that. You wouldn't save more than a tiny handful of change. When someone has a really complicated 120+ foot wiring run or something, then yes, there's probably going to be realistic cost savings that might be worth it.

 

[Art84]

Agreed with the previous two replies. Find a new electrician.

 

[ucmndd]

Do it right the first time. Go the full 60 amps if your panel can support it and DON’T terminate aluminum wire directly to the wall connector.

Find an electrician that isn’t trying to cut needless corners.

 

[qdeathstar]

Use #6 copper for the entire run in conduit, don’t bother with any other solutions. Any pig tailed connection will eventually fail so I would not recommend that.

You only need two #6 conductors. You can use #10 for the equipment ground, or no wire if you use metal conduit and bonding bushings… I usually just run the third wire.

 

[240vPlug]

Agree with everyone here,. Get an opinion from another electrician.

Run copper and use a 60 amp breaker if at all possible. This is not a place where you want to try and cut costs. The stakes are high so do the job right and rest easy moving forward.

 

[howardnj]

When i decided to order a Tesla, I decided to use a recommended local electrician from the Tesla website. I'm glad that I did.
They ran 150 ft of #2 aluminum cable from my 200 amp basement panel to the 100 amp sub panel in my garage with 60 amp breakers and installed my Tesla HPWC using copper so I charge nightly at 48 amps. They did excellent work.
They did not use cheap materials from Home Depot but acquire all the needed materials from a local electrical supply house. They filed for the necessary permit and inspection, submitted the required load/data form to NJ PSE&G so I qualified for the $1500 EV rebate.
My advice is do not go cheap, obtain proper permits, and don't risk a fire or end up with a home insurance problems.
You just add the cost to the price of your first EV just like you added options on previous ICE vehicles.

 

[ChrisMPK]

Aluminum wire should really only be used for feeding a sub panel a long distance from a main panel. This is absolutely the wrong use for it. Also, if you aren't limited by capacity on your panel, run a 60A circuit for your charger. The cost difference is negligible, and assuming that you always have surplus time at night to charge this or any other electric vehicle for the next 20 years is going to be wrong at some point. Your schedule may change, the vehicles you own may change, the occupants of your house may change, and your electric TOU rates will definitely change given a long enough timeline. Most of the advise on this forum about charging comes from someone telling you what works for their schedule now. You probably aren't going to revisit this project for many years (nor should you), so think longer term.

 

[boulder.dude]

Even if you use a 50A circuit breaker, run wire for the full 60A to future-proof. EV batteries will only get bigger and maybe someday you’ll have two.

 

[Hookemhorns]

I am NOT an electrician. I am a mere user....

Our first house had aluminum wiring. The latest and greatest thing, they told us. In the 3 years we lived there, sockets were going out all the time. It appeared the wire heated too much when it was in use, and loosened the screws. Finally there was insufficient contact. I'd pull them out of the wall, tighten the screws, curse the builder, and replace them. They then worked like a champ for months.

I have no doubt a real electrician who says they are OK is right. But I would pay extra for copper. Just me.

 

[boulder.dude]

I am NOT an electrician. I am a mere user....

Our first house had aluminum wiring. The latest and greatest thing, they told us. In the 3 years we lived there, sockets were going out all the time. It appeared the wire heated too much when it was in use, and loosened the screws. Finally there was insufficient contact. I'd pull them out of the wall, tighten the screws, curse the builder, and replace them. They then worked like a champ for months.

I have no doubt a real electrician who says they are OK is right. But I would pay extra for copper. Just me.

Scary! Bare aluminum wire forms an electrically resistive coating if it is in contact with air for long periods of time. This causes the connection to get warmer and warmer, burning your house down.

This is the reason for adding (air sealed) copper ‘pigtails’ to the ends of aluminum wiring.

Stick with copper for home use!

 

[L_Mont]

Aluminum wires are used for electrical wiring but you have to use an anti-oxidant compound at each connections when exposed to air.
Search: "Noalox Anti-Oxidant Coumpound"

 

[ATPMSD]

If you decide to run 60-amp wire make sure it is real 60-amp wire. Too many electrians run things like #6 Romex, which is rated at 55-amps, not 60.

 

[ucmndd]

The wall connector install manual says very clearly use only copper conductors. Anti oxidant or not. Just don’t do it.

 

[fiehlsport]

Aluminum wires are used for electrical wiring but you have to use an anti-oxidant compound at each connections when exposed to air.
Search: "Noalox Anti-Oxidant Coumpound"

I believe recent changes to the composition of aluminum wiring in the last 0-5 years has negated the need for Noalox. Regardless, I used it when I wired my subpanel. But a good thing to keep in mind regardless, and it doesn't hurt to use it.

 

[Depwraith]

I ran 4 gauge copper. Never seen so many people worry about such a minimal cost compared to the vehicle. Future vehicle will charge faster and you're gonna want that extra.

 

[howardnj]

The wall connector install manual says very clearly use only copper conductors. Anti oxidant or not. Just don’t do it.

#2 Aluminum is used for long indoor runs between the basement 200 amp panel and the 100 amp sub panel located in the garage. The proper copper cable is then run out of the sub panel to the HPWC and any additional garage outlets.
This work should only be done by NJ licensed electricians that apply for the proper permits, use high quality materials, and fill out the required load/data form to PSE&G to qualify for the $1500.00 rebate. This work is not for inexperienced handymen if you want to avoid possibly burning down your house in the middle of the night

 

[Ipcress]

Thanks for these informative replies! Going with full copper and 60 amp.

 

[vlee]

Is that a 5-15 outlet on the inside of your 200 amp basement panel?