Tesla Wall Charger installed - 50 amp instead of 60 amp

[Netzero71]

I just got the Tesla wall charger gen3 installed. The electrician brought a 50 amp breaker instead of 60 amp. He said he will come back to swap the break. However, looking at the app and charging right now, I'm getting 41 mi/hr at 40a which is slightly higher than the 37 mi/hr as stated on the installation manual.

Question, what are your experiences with 60 amp breaker output? Is it worth asking the electrician to come back and swap the 50 amp for 60 amp breaker?

 

[jjrandorin]

Are you sure its 41mph at 40amp (are you sure the wall connector is configured for a 50 amp breaker (40 amp charging) and not a 60 amp breaker (48 amp charging)?

Sounds to me like the wall connector is configured for a 60amp breaker which is 48amp charging.

 

[Sophias_dad]

And of course, what kind/gauge of wire is connecting the HPWC to the panel. I'm wagering its not 48A continuous-capable. Needs to be #4 NMB or #6 if its conductors-in-conduit. (Lower numbers are better, so #6 NMB is not supposed to be used for 60A(48A continuous))

 

[UncleCreepy]

He said he will come back to swap the break. [...]

Is it worth asking the electrician to come back and swap the 50 amp for 60 amp breaker?

You're not asking him to come back if he already said he'll be back.

Sounds like he didn't have a 60A breaker at hand and temporarily installed a 50A breaker. No reason not to swap it once it's available.

 

[Netzero71]

Are you sure its 41mph at 40amp (are you sure the wall connector is configured for a 50 amp breaker (40 amp charging) and not a 60 amp breaker (48 amp charging)?

Sounds to me like the wall connector is configured for a 60amp breaker which is 48amp charging.

Here is a screenshot from my phone. and yes, it is a 50 amp because he will come back for the 60 amp. I also did setup the charger for 50 amp.

 

[ucmndd]

Miles/hour is variable by model given the varying efficiencies of each model/trim/battery configuration. The value in the manual is an average. Don’t get hung up on it as it’s not a definitive measure of charging power in the way volts and amps are.

It’s like measuring the flow rate of a gas pump in miles per hour. The same pump might add “120 miles per minute” to a Prius but only “40 miles per minute” to an F-150.

 

[RayK]

If your electrician has done a load analysis and come to the conclusion that a 60A breaker (48A continuous) is allowed AND the wiring in place is able to safely handle the 48A, then sure, let him swap in a new 60A breaker if you think that you really need the extra 5-7MPH boost in charging.

 

[ATPMSD]

Needs to be #4 NMB or #6 if its conductors-in-conduit.

@Netzero71

This is an extremely important point as all too often electricians do not run wire the appropriate wire for a 60-amp circuit, so double check with him. If it is…

#4 NMB that is good
#6 NMB is not and you must leave it as a 50-amp circuit
#6 THW/THWN is also good
#8 THW/THWN is not

 

[Netzero71]

@Netzero71

This is an extremely important point as all too often electricians do not run wire the appropriate wire for a 60-amp circuit, so double check with him. If it is…

#4 NMB that is good
#6 NMB is not and you must leave it as a 50-amp circuit
#6 THW/THWN is also good
#8 THW/THWN is not

not sure which one. it is #6 for sure, but how can I quickly tell which one?

 

[ATPMSD]

not sure which one. it is #6 for sure, but how can I quickly tell which one?

If the wires are in a protected covering, it is most likely NMB. If the wires are not in a protected covering it is probably THW/THWN. But you have to be careful as if you only see the wires in the wall connector this will not tell you much as the covering is typically removed as it enters the wall connector.

You can also look at the wires for a marking such as THW/THWN. If you post a photo we may be able to help, but of course your electrician will know for sure.

 

[davewill]

If it was run inside the walls, good bet it's NM-B. If it was run in conduit, THHN.

 

[Netzero71]

The feedback I'm loo

If it was run inside the walls, good bet it's NM-B. If it was run in conduit, THHN.

in wall - black cover for all wires and then 3 covered wires + ground

 

[ATPMSD]

You can confirm with the eletrician but that sure sounds like NM-B. If it is in fact #6 wire then you are restricted to 50A, so you should not replace the breaker.

 

[ewoodrick]

The way way that this works is that the car should work well on a 50A circuit and charging at 48A. But that does NOT pass code. Situation is that configured that way, (and assuming that the wiring is sized to support it) heating will be occurring on the circuit. It probably won't mean anything on Day 1. Probably won't mean much on Day 60. May not mean anything on Day 365. But on any of these days as well as further into the future, the heating of the wires will cause abnormal heating of everything around it and bad things start happening. And one evening you may wake to the smell of smoke.

Any circuit that operates in a "continuous" mode (EVs definitely do) must be rated at only 80% of what the circuit can handle. So both the wire and breaker must be rated for 60A if charging at 48A.
Why did Tesla choose 48A as the max charging rate? It happens to be 80% of 60A, the largest general plug that you will have in residences.

 

[nickkovach]

So my electrician also wired my gen 3 Tesla charger with a 50amp and I was surprised to see i am limited to 32a when charging my 2023 model 3sr+ (LFP battery of course). I read the car limits itself to 32a (but a performance model 3 can pull more?) so I figured it’s not worth arguing for 60a in my case.

 

[Sophias_dad]

So my electrician also wired my gen 3 Tesla charger with a 50amp and I was surprised to see i am limited to 32a when charging my 2023 model 3sr+ (LFP battery of course). I read the car limits itself to 32a (but a performance model 3 can pull more?) so I figured it’s not worth arguing for 60a in my case.

Yes, the long range versions(aka P or AWD) have a 48 amp charging circuit.

 

[ewoodrick]

So my electrician also wired my gen 3 Tesla charger with a 50amp and I was surprised to see i am limited to 32a when charging my 2023 model 3sr+ (LFP battery of course). I read the car limits itself to 32a (but a performance model 3 can pull more?) so I figured it’s not worth arguing for 60a in my case.

You'll probably never notice the difference in charging between 32A and 48A. They'll both be finished in the middle of the night before you need them

 

[UncleCreepy]

You'll probably never notice the difference in charging between 32A and 48A. They'll both be finished in the middle of the night before you need them

That is something I frequently read from people who live in warmer climates, and they are absolutely right based on where they live (assuming they use their car once during the day). OP lives in Boston though where it can get pretty cold. This is my fourth winter with a Tesla in Ontario and trust me, when it gets down to -20 or - 30 °C (-4/-22F), you'll want to use all the power you can get to get the battery charged. Even on a public 10 kW charger that I frequently use the charging sometimes goes down to just a few kph because the battery needs to be reheated. In other words, the charging process is not generating enough heat to maintain the battery temperature. This would be even worse with less available power. That alone was reason enough for me to replace the existing wiring to my garage so I could install and set up the WC for 48 Amps.

Point is, there is no "one size fits all". Some folks might be okay with Level 1 charging, others need all the power they can get.

 

[SageBrush]

Question

The important first question here is:
What wire was installed ?

You DO NOT WANT to be in a position where the breaker is not protecting the wire

 

[RISC601]

With a 60 amp breaker and the Tesla Wall Charger my 2021 Model 3 pulls 48 amps and charges @ 49-50 mph.