Aluminum wire for Tesla wall connector

[rickybobbee]

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.

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!

get a new electrician. This guy doesn't know what he's doing. The cost difference he is talking about is pennies and taking short cuts with wire.........red flags everywhere. He wants to use a 50 amp because he took it from someone elses house that replace a 50 with a 60amp breaker from a hot tub or something

 

[howardnj]

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

It is 120v outlet that is required under our local code. So are the painted black plywood backboards in both my basement 200 Amp panel and the 100 Amp garage sub panel. When you hire a local NJ licensed experienced electrician you end up with a top quality inspected and approved job and not have to worry about possibly setting the house on fire in the middle of the night. NJ licensed electricians do not use cheap materials from home Depot made in China, but obtain all of their supplies from an electrical supply house. This is why a top quality job costs more and you just add that cost as an option to your first EV. I've already received my $1500 rebate from NJ PSE&G to off set the cost of a proper installation. I charge my Y nightly at 48 Amps in my garage.

 

[MdlYYY]

I do not recommend aluminum wire for anything other than a temporary application! Only use copper!

 

[vlee]

It is 120v outlet that is required under our local code.

I was actually referring to this thing. Looks like an outlet inside the panel? Just curious to learn more about that.

 

[howardnj]

I was actually referring to this thing. Looks like an outlet inside the panel? Just curious to learn more about that.
View attachment 869518

That is the main on/off breaker for the entire 200 Amp panel

 

[iRia]

I would even upsize the wire to 4AWG if you can to minimize voltage drop. Especially if it’s a long run.

 

[ucmndd]

I would even upsize the wire to 4AWG if you can to minimize voltage drop. Especially if it’s a long run.

This is really completely unnecessary for all but the very longest runs.

#6 copper at 240v/48a will result in a ~1.6% voltage drop over 100 feet (i.e. 3.8 volts).

#4 copper at the same length results in a ~1.0% voltage drop (i.e. 2.4 volts).

At my local Home Depot #4 THHN is 80 cents more a foot than #6. Is it worth an extra $160 in materials (before accounting for other needs like upsized conduit) to prevent a 1.4 volt drop? I guess you can be the judge.

 

[Art84]

At my local Home Depot #4 THHN is 80 cents more a foot than #6. Is it worth an extra $160 in materials (before accounting for other needs like upsized conduit) to prevent a 1.4 volt drop? I guess you can be the judge.

So don't shop in Home Depot. Shop online.
THHN/THWN-2 Copper Wire | WireAndCableYourWay.com

 

[ucmndd]

So don't shop in Home Depot. Shop online.
THHN/THWN-2 Copper Wire | WireAndCableYourWay.com

Does anything I said fundamentally change if the difference per foot is 53 cents (plus shipping) instead of 80 cents?

 

[Art84]

View attachment 869868

Does anything I said fundamentally change if the difference per foot is 53 cents (plus shipping) instead of 80 cents?

Yes, it does!
Because the price per foot for #6 THHN in Home Depot ($1.46) is almost the same as $4 THHN if shopping in other places ($1.55). So why not go with #4?
From this perspective, you don't save much and it's not about a $160 difference as you have mentioned.

 

[ucmndd]

So why not go with #4?

Because it provides zero benefit. There’s absolutely no reason to for any normal-length run.

If you’re that price conscious, you should get the cheapest option from the cheapest outlet that meets the needs of the installation (i.e. #6). Any way you cut it, spending extra money for no good reason is goofy.

Setting aside for the moment that we’re ignoring shipping costs, which will eat into any online “savings” pretty quickly.

Anyway. Be cool boss man. You do you.

 

[GWord]

So why not go with #4?

The difference is 67 watts on a 48A load (using the run lengths discussed earlier), resulting in a savings of 1min 45sec on a 5h charge. As far as valuing time, that seems like an expensive 1.75 minutes.

 

[dgbehrends]

Great explanations here. I used 6/3 MC at it was $5.5 a foot vs 4/3 NMB for $11 a foot for a 60amp breaker install. My run was 50 feet so it made a big difference in price. I wanted to get the fastest charge possible knowing that there was going to come a time where an unexpected trip was needed and getting the car charged up as much as possible was important.

 

[Nubo]

The difference is 67 watts on a 48A load (using the run lengths discussed earlier), resulting in a savings of 1min 45sec on a 5h charge. As far as valuing time, that seems like an expensive 1.75 minutes.

That is also 335 watt-hours over the course of 5 hours, so there is an electricity cost savings. Small, but over time... Perhaps more significant is the extra margin of safety as the thicker conductors will pull more heat away from any hot spots, keeping connections running cooler. People tend to not appreciate that this kind of heavy continous load is unprecedented in many households. Even electric ovens or large HVAC systems cycle during use.