Wall Connector Gen3: Future-proofing with 60A breaker?

[Zinzan]

I have a 2021 SR+, and have been using a NEMA 14-50 outlet since last June. It's been great.

However, as good as this is, I couldn't resist ordering a Wall Connector as I am moving to a new house where I don't plan to move for many, many years.

I know the SR+ can only charge at a max rate of 32A, so if I'm understanding correctly, I only need a 40A breaker. But should I consider just going ahead and having a 60A circuit installed for future-proofing? There's probably a greater than 0% chance this isn't my last Tesla (and probably an even better chance this isn't my last EV), and the next one, whether for me or my wife, may have a higher max charge rate. The electrician says the cost difference is negligible.

If I go ahead with a 60A breaker, is there anything to be careful or concerned about? The onboard charger will make sure I don't draw too much, just as it currently does with my mobile connector on the 14-50 outlet, right? But in the meantime, if I have guests with a more powerful Tesla, they can benefit from a faster charge.

Thanks in advance for any information or advice.

 

[Zinzan]

P.S. He will be installing 6 gauge copper, regardless.

 

[SilverString]

The prudent move would be to have the breaker rating equal to or less than the outlet rating even if you pull #6 copper. Most use a 50 amp breaker for the mobile charger and a NEMA 14-50 industrial grade outlet. If/when you get your HPWC installed just pop in a 60 amp breaker. That said I doubt that you would ever have a problem with your existing plan.

 

[STS-134]

P.S. He will be installing 6 gauge copper, regardless.

60A breaker will protect a wire that's capable of taking 60A of current. Installing an oversized breaker (or a wire that's undersized for the breaker) is not allowed because you can draw too much current, heat up the wire, and cause a fire (however you are allowed to undersize the breaker or oversize the wiring because there is no fire risk associated with doing this). If you want a 60A breaker, install 4 gauge wiring. It's probably cheaper to do this now than to have the electrician come back and have to rip out the 6 gauge and replace it with 4 gauge in the future. If you really want to future proof your setup, install 2 gauge wiring with a 60A breaker; you'd be able to reuse the wiring for a future 80A EVSE if Tesla ever starts making them again, or if you get an EV like a Rivian or Lucid that has an 80A OBC. But note that the Gen 3 WC only allows you to connect wires as big as 4 gauge, so you'd need the electrician to do some extra work to make the connection from the 4 gauge wiring to the 2 gauge wiring just before the wires enter the WC.

 

[Rodney!]

I am going whole hog on the future proofing... I am running 3awg copper for a dedicated 100amp wall charger circuit for my Gen2, but installing a 60amp breaker as my M3 can only charge @48 amps currently.

The wire/conduit price is ~$120 difference, but I will only have to do the install labor just once. In the event that Tesla ups their charging capability, or I get a Ford Lightening (which charges @80amps). That was I will only have to swap the breaker and the amp dial on the Tesla charger or swap the charger head.

I will probably sell the house before that happens, but hey, it will be done for the new owner...

 

[Gauss Guzzler]

Yes, 60A and 6 AWG are perfect. That's plenty of power to charge even the most inefficient Hummer overnight, should you find yourself commuting 300 miles/day in such a monstrosity.

No need for any crazy wire sizes but your "future" will likely include a second EV so consider power on both sides of the garage.

 

[Zinzan]

The prudent move would be to have the breaker rating equal to or less than the outlet rating even if you pull #6 copper. Most use a 50 amp breaker for the mobile charger and a NEMA 14-50 industrial grade outlet. If/when you get your HPWC installed just pop in a 60 amp breaker. That said I doubt that you would ever have a problem with your existing plan.

Yes, I have 6 AWG, 50A breaker on my current NEMA 14-50 industrial grade outlet setup (house I'm selling). And it's not a matter of if on the HPWC--I already have it ready for install at my new house.

60A breaker will protect a wire that's capable of taking 60A of current. Installing an oversized breaker (or a wire that's undersized for the breaker) is not allowed because you can draw too much current, heat up the wire, and cause a fire (however you are allowed to undersize the breaker or oversize the wiring because there is no fire risk associated with doing this). If you want a 60A breaker, install 4 gauge wiring. It's probably cheaper to do this now than to have the electrician come back and have to rip out the 6 gauge and replace it with 4 gauge in the future. If you really want to future proof your setup, install 2 gauge wiring with a 60A breaker; you'd be able to reuse the wiring for a future 80A EVSE if Tesla ever starts making them again, or if you get an EV like a Rivian or Lucid that has an 80A OBC. But note that the Gen 3 WC only allows you to connect wires as big as 4 gauge, so you'd need the electrician to do some extra work to make the connection from the 4 gauge wiring to the 2 gauge wiring just before the wires enter the WC.

Are you suggesting that 6 AWG is insufficient for 60A breaker?

I am going whole hog on the future proofing... I am running 3awg copper for a dedicated 100amp wall charger circuit for my Gen2, but installing a 60amp breaker as my M3 can only charge @48 amps currently.

The wire/conduit price is ~$120 difference, but I will only have to do the install labor just once. In the event that Tesla ups their charging capability, or I get a Ford Lightening (which charges @80amps). That was I will only have to swap the breaker and the amp dial on the Tesla charger or swap the charger head.

I will probably sell the house before that happens, but hey, it will be done for the new owner...

I wouldn't say I desire to go whole hog on future proofing. Just some reasonable future-proofing like getting the most out of my new Gen 3 HPWC, should I get a different Tesla in the future (only going by current max charge rates, not future vehicles that may charge even higher than 48A. If I do get an EV one day with a higher possible max charge rate, I think I can continue to get by with 48A max charge rate, as my daily commute is not long.

But yeah, if you have big plans, and/or have a Gen 2 that you want to get the most out of, then sounds like a good idea if you can swing it now.

Yes, 60A and 6 AWG are perfect. That's plenty of power to charge even the most inefficient Hummer overnight, should you find yourself commuting 300 miles/day in such a monstrosity.

No need for any crazy wire sizes but your "future" will likely include a second EV so consider power on both sides of the garage.

Thanks, @Gauss Guzzler. So if going with this plan for the HPWC Gen 3 install, no concerns about the circuit, or any particular configuration/settings to make with HPWC or on my M3 SR+?

 

[Big Dog]

yes, definitely go for the 60 amp if you have space in your electrical box. The labor cost is the same, and the heavier gauge wire is only a few extra bucks.

 

[Gauss Guzzler]

Yes @Zinzan 6 AWG is the "correct" size for a 60A circuit but with the caveat that it needs to be individual wires in conduit, not a molded Romex cable. Surely your electrician knows this but if Romex is preferred for any reason, you can simply use a 50 breaker and set the semi-permanent HPWC limit to 40A. Configuring the charger for a limited circuit is easy, just connect to the charger's Wi-Fi using the password in the quick start guide and select the appropriate limit.

Your 3SR will always charge at whatever rate is lower - either the car's limit of 32A or the limit of whatever charger you connect it to. Even with adapters to generic chargers that could be 12A or 60A or anything in between, all EV's will safely auto-negotiate the best charge rate with all chargers.

 

[STS-134]

Are you suggesting that 6 AWG is insufficient for 60A breaker?

For longer runs and multiple wires together in the same cable, yes.

Yes @Zinzan 6 AWG is the "correct" size for a 60A circuit but with the caveat that it needs to be individual wires in conduit, not a molded Romex cable. Surely your electrician knows this but if Romex is preferred for any reason, you can simply use a 50 breaker and set the semi-permanent HPWC limit to 40A.

Do you trust Tesla's software team to properly preserve this software-controlled current limit? Note that unlike the situation with the Gen2 WC (where the current limit was controlled by a physical switch that had to be rotated to a certain position), the Gen3 WC limits the current only with software. And given what I have seen from Tesla's software team, I don't trust them to properly preserve the setting. Now in theory, this is okay, because you've still got the 50A breaker, but you're not supposed to run 48A of continuous load through a 50A breaker, nor through 6AWG wire that's got multiple wires in the same cable or is very long. The problem is, the breaker won't trip and let you know that you've got a problem.

 

[terranx]

For longer runs and multiple wires together in the same cable, yes.

Why are you assuming he has a long enough run and / or enough wires to necessitate derating the cable? 6AWG is sufficient for the vast majority of cases

Do you trust Tesla's software team to properly preserve this software-controlled current limit? Note that unlike the situation with the Gen2 WC (where the current limit was controlled by a physical switch that had to be rotated to a certain position), the Gen3 WC limits the current only with software. And given what I have seen from Tesla's software team, I don't trust them to properly preserve the setting. Now in theory, this is okay, because you've still got the 50A breaker, but you're not supposed to run 48A of continuous load through a 50A breaker, nor through 6AWG wire that's got multiple wires in the same cable or is very long. The problem is, the breaker won't trip and let you know that you've got a problem.

Believe it or not, software in the gen 1/2 connectors has to interpret the dipswitch position to enforce a current limit. I trust an NVRAM variable about as much as I trust a dipswitch.

Not sure why you feel the need to fear monger.

 

[STS-134]

Why are you assuming he has a long enough run and / or enough wires to necessitate derating the cable? 6AWG is sufficient for the vast majority of cases

My electrician installed 4/3 Romex for my 48A WC. Whether it was because it was Romex or because of the length of the run or both, I never really asked.

Believe it or not, software in the gen 1/2 connectors has to interpret the dipswitch position to enforce a current limit. I trust an NVRAM variable about as much as I trust a dipswitch.

Not sure why you feel the need to fear monger.

At least the software is taking its input from a physical switch instead of just some bits in flash memory that can be ignored. Simplest solution to the problem though is to just assume that the software will be faulty and will reset to allowing a vehicle to pull a full 48A, and design the wiring and breaker accordingly. ESPECIALLY for a new install. A 60A breaker takes up just as many panel slots as a 50A or a 40A. There's no reason to try to de-rate the WC to a lower amperage unless you're using an existing circuit and trying to avoid having to run new wiring.

 

[Summoner12]

#6 copper is rated at 65amps at 75*C. So long as the three wires are the only ones in the conduit. Add more than three, and you'll need to derate them and you'll need larger wire.

BTW, this is COPPER, not aluminum. If you run aluminum you'll need to go with a larger wire size.

If you have power near the location of your charger, don't worry TOO much about wire future proofing. I would be more concerned with the conduit being run than the wire, if it's close to the main home power panel. If you have a long run to the power source, maybe consider a sub-panal for the garage, run big stuff, like 1/0 or 2/0 for a 100amp sub. then you can have a wall of chargers to pick from.

 

[terranx]

My electrician installed 4/3 Romex for my 48A WC. Whether it was because it was Romex or because of the length of the run or both, I never really asked.

At least the software is taking its input from a physical switch instead of just some bits in flash memory that can be ignored. Simplest solution to the problem though is to just assume that the software will be faulty and will reset to allowing a vehicle to pull a full 48A, and design the wiring and breaker accordingly. ESPECIALLY for a new install. A 60A breaker takes up just as many panel slots as a 50A or a 40A. There's no reason to try to de-rate the WC to a lower amperage unless you're using an existing circuit and trying to avoid having to run new wiring.

It’s because it’s romex. Those are rated for less current than thhn or mc cable.

Software can just as easily ignore a physical switch as it can flash memory. I agree if you’re doing a new install you might as well go for the max capacity, but there are reasons you wouldn’t do that (reusing existing wiring being a big one)

 

[Zinzan]

In regards to the distance, the panel is in the unfinished basement on the other side of the house, so the run is probably around 50 feet. The basement is framed but open straight to the bottom of the garage wall so the wire run should be fairly easy.

 

[Zinzan]

In regards to the distance, the panel is in the unfinished basement on the other side of the house, so the run is probably around 50 feet. The basement is framed but open straight to the bottom of the garage wall so the wire run should be fairly easy.

I can no longer edit this message, but wanted to add/clarify a few things:

The basement is framed but open (no drywall or ceiling in place yet) to the bottom of the garage wall, and it would be a straight shot along a single basement ceiling beam, so the wire run should be fairly easy.

Given the run distance, does that change the recommendations on wiring? If I go 60A breaker, molded Romex 6AWG is not advised, and I would need individual wires in conduit (even though the entire run would be within walls and ceiling (that aren't yet covered)?

Else, if I go 50A breaker, molded Romex 6AWG is fine, but I would also want to configure the HPWC with that info?

 

[Rocky_H]

Given the run distance, does that change the recommendations on wiring?

No, you were mentioning it's approximately 50 feet, which isn't very long anyway. It may have an extra 2 or 3 volts drop, but that's not a big deal, and the car and charging equipment won't care.

If I go 60A breaker, molded Romex 6AWG is not advised, and I would need individual wires in conduit (even though the entire run would be within walls and ceiling (that aren't yet covered)?

Right, the 6 gauge Romex is only rated for up to 55A circuits, so can't be used on a 60A circuit. But then you jump to needing conduit, and I would say no, that's not the case. Where you are physically putting the wire run is usually the main thing that determines whether it is more appropriate to go for Romex or wires in conduit. But then you just need to pick the appropriate gauge. It sounds like trying to install conduit all along all of this is going to be more troublesome, so Romex sounds like the fine choice to string it up easily. But then you just need to go up to 4 gauge instead of 6 gauge to meet the requirement for a 60A circuit.

 

[Gauss Guzzler]

Straight-shot conduit is really cheap, easy, and would be fully code-compliant right off the bat with or without drywall. But it's a bit of a hassle to zig-zag thru joists and stuff. The loose wire has to be in conduit whether it's inside a wall or not. It can be flexible conduit though, if that helps.

4/2 Romex is reasonably easy to string up and staple in place but should have drywall or something to protect it. But 4 gauge Romex isn't always easy to find.
6/2 Romex is a bit cheaper but yes you'd give up 20% of your charge speed by configuring the HPWC to 40A. Probably not worth the minimal savings for a 50' run.

 

[Jeremy3292]

@Zinzan

6 gauge THHN hot wires, 10 gauge THHN ground wire, 60 amp breaker, and the Tesla wall connector.

Done and done. Don’t over complicate it.

 

[Rocky_H]

Done and done. Don’t over complicate it.

Doing conduit where you don't need to and Romex is more appropriate would be over complicating it.