Wall Charger what amp for breaker

[bgrynn1873]

Had an electrician install a gen 3 wall charger. So line and everything is able to handle 6 gauge. It could easily handle a 60 amp breaker as the wire and panel can handle it but at the time of install he only had a 50 amp breaker so I had him just install the 50 amp breaker since it's easy to swap out later if I want to.

After some reading I am starting to think maybe 50 amp is just fine and perhaps actually better since it be better for the battery and at the end of the day not a big deal.

So question is should I upgrade the panel or just not worry about and charge at 40 instead of 48 since it will be more then enough.

 

[jimmythefrack]

for 6 guage wire you can only run 50 amps you would need 4 gauge wire for 60 amps

 

[bgrynn1873]

[

for 6 guage wire you can only run 50 amps you would need 4 gauge wire for 60 amps

It's actually spec to 60 amp with the correct gauge made a mistake it is 4 guarge wire.

Anyways I was thinking running the charger at 50 amps is probaly a lot better for everything including the charger since I see reports of the cord getting hot at 48amps. If that is the case then I rather run the charger a little less amps. The extra 8 amps is not going to big deal in the real world application of charging.

 

[iluvmacs]

for 6 guage wire you can only run 50 amps you would need 4 gauge wire for 60 amps

That depends on wire type. For instance, THHN #6 can do 60A, but NM-B (Romex) is rated 55A, making it only good for a 50A circuit as you say.

 

[Rocky_H]

After some reading I am starting to think maybe 50 amp is just fine and perhaps actually better

Sure, I think that usually serves pretty well for at home charging levels.

since it be better for the battery

No.

is probaly a lot better for everything including the charger since I see reports of the cord getting hot at 48amps.

Yes, probably.
Concern for the battery doesn't make any sense. You're quibbling about the power difference between 10 kW or 11.5 kW. These are battery packs that can charge at 200+ kW. I assure you the battery doesn't give a $&*t about 10 or 11.5. All home charging levels are very slow from the battery's perspective, so don't worry about that.

However, your concern for heat in the charging connectors is pretty well founded. Tesla has a bit of history of being barely marginal on some of their charging cables and equipment, and I'm already seeing reports of the gen3 wall connectors getting pretty hot running at that 48A maximum. So yes, to probably extend the life of your charging equipment, you may be helping by running them a bit below max to keep them cooler.

 

[paulk]

i think in your situation id put in the 60 amp breaker and set the car to charge lower. ive got my cars set to charge at 40 amps regularly, but if im in a rush i can increase the model S to 72 amps and the model 3 to 48 amps.

 

[bgrynn1873]

Sure, I think that usually serves pretty well for at home charging levels.

No.

Yes, probably.
Concern for the battery doesn't make any sense. You're quibbling about the power difference between 10 kW or 11.5 kW. These are battery packs that can charge at 200+ kW. I assure you the battery doesn't give a $&*t about 10 or 11.5. All home charging levels are very slow from the battery's perspective, so don't worry about that.

However, your concern for heat in the charging connectors is pretty well founded. Tesla has a bit of history of being barely marginal on some of their charging cables and equipment, and I'm already seeing reports of the gen3 wall connectors getting pretty hot running at that 48A maximum. So yes, to probably extend the life of your charging equipment, you may be helping by running them a bit below max to keep them cooler.

From the sounds of it the concern over the Ten 3 wall connector is a real issue. If the connector gets a little warm at 48amps then there probaly pushing it. I think I will stick with the 40 amp setting and breaker if I need more power I will change the breaker. I sort of feel it I need to charge it in a hurry then I need to be using a supercharger anyways.

 

[empiredown]

I’ve had a Gen 3 installed in a TX garage since March. The temp in this non HVAC’d garage is regularly 90 degrees or above. ZERO ISSUES and it charges at 48 amps / 12 kW sustained. The cable does get warm, but it’s supposed to as that’s the way physics works. I wouldn’t let a couple, unfortunate, bad examples sway you.

If your provision it properly, don’t play games with the breaker or your wiring, and use it in accordance with its design odds are you’ll be fine. Let’s, please, not let this get out of hand like “all” the Y horror stories that took on a life of their own and had everyone playing Chicken Little for months. Faults and errors happen, but the silent majority is the largest part of the bell curve.

ß

 

[wondering]

If you want to charge at 48, you can with a 60 amp breaker. #6 romex is good for 55 amps and you size the breaker by going to the next size which is 60 amps. You can only run breakers continuously at 80% of their trip setting. 60 amps times 80% is 48 amps. It sounds like you are good to go once you swap the 50 amp breaker out to 60 amp and change the setting in the Gen3 charger.

 

[Rocky_H]

If you want to charge at 48, you can with a 60 amp breaker. #6 romex is good for 55 amps and you size the breaker by going to the next size which is 60 amps. You can only run breakers continuously at 80% of their trip setting. 60 amps times 80% is 48 amps. It sounds like you are good to go once you swap the 50 amp breaker out to 60 amp and change the setting in the Gen3 charger.

No, no, NO! Fortunately, the OP doesn't have what you are describing, as the follow up message said he found he actually has 4 gauge wire, so that's all good for his situation.

But you are giving blatantly wrong info about how this works with electrical code, and I don't want someone to make a bad mistake from taking your advice.

#6 romex is good for 55 amps

True.

and you size the breaker by going to the next size which is 60 amps.

Technically you could, but you are not understanding what that means. You go on with the assumption that because you have physically placed a 60A breaker on it, that it now becomes a real certified 60A rated circuit. But that is not true; lowest limitation still applies. It's still only 55A rated because of the wire limitation that happens to have an oversized breaker.

You can only run breakers continuously at 80% of their trip setting.

(My bold added) So this is where you're getting this wrong. It's not just about the breaker. You are only allowed to run a circuit at 80% of its rating continuously. And that has to pass the limitations throughout the whole circuit: outlet or appliance connection, wire, and breaker.

60 amps times 80% is 48 amps.

But it's not a 60A circuit. It's a 55A circuit, so you can't run it higher than 44A.

It sounds like you are good to go once you swap the 50 amp breaker out to 60 amp and change the setting in the Gen3 charger.

You can't use the 60A setting, because that would run at 48A continuous, which isn't allowed on a 55A circuit, which can only do 44A continuous, etc.

So all this to say, that is why no one ever recommends using that oversize breaker technicality with 6 gauge Romex--because it can incorrectly fool people into thinking that makes it into a 60A circuit when it really isn't. The wire capability means it's only 55A max, so you're best to just breaker it as a 50A circuit.

Sorry if I'm coming across as harsh, but what you are recommending is dangerous.

 

[everydaychris]

Sweet mercy. So what do I tell the electrician? 60 AMP 6 gauge ?

I'm so confused haha.

 

[Rocky_H]

Sweet mercy. So what do I tell the electrician? 60 AMP 6 gauge ?

I'm so confused haha.

You don't really have to tell an electrician every detail. They will know how to comply with code. Just tell them if you want a 50A circuit or a 60A circuit. They will pick the right wire size and breaker and will not do those kinds of hokey stupid tricks like I was having to warn against above.
But if you do want to learn more about it, here is where to start:
Ampacity Charts - Cerrowire

This table shows the wire gauge for various types of wire and how many amps they are allowed to run. That first column, that says "NM-B" is the stuff people refer to as Romex cable. It has multiple wires bundled together inside a rubber sheath. That is marked for a 60 degree C heat limit. That is for running directly inside insulated walls. The next column (75 degrees C) has the stuff that would be individual wires running inside a conduit, like along the outside surface of a wall. And you will notice that for a same wire gauge thickness, it does allow a higher current, because it is able to dissipate the heat better.

It's pretty straightforward if you just follow the limits.
So for a 50A circuit, you could do 6 gauge Romex or 8 gauge wires in conduit. Although, that's right at the 50A limit, so I would still recommend 6 gauge in that case too.
For a 60A circuit, you can see that it would be either 4 gauge Romex or 6 gauge wire in conduit.

 

[hcdavis3]

Sure, I think that usually serves pretty well for at home charging levels.

No.

Yes, probably.
Concern for the battery doesn't make any sense. You're quibbling about the power difference between 10 kW or 11.5 kW. These are battery packs that can charge at 200+ kW. I assure you the battery doesn't give a $&*t about 10 or 11.5. All home charging levels are very slow from the battery's perspective, so don't worry about that.

However, your concern for heat in the charging connectors is pretty well founded. Tesla has a bit of history of being barely marginal on some of their charging cables and equipment, and I'm already seeing reports of the gen3 wall connectors getting pretty hot running at that 48A maximum. So yes, to probably extend the life of your charging equipment, you may be helping by running them a bit below max to keep them cooler.

Rocky is the only guy you should trust...period.

 

[everydaychris]

You don't really have to tell an electrician every detail. They will know how to comply with code. Just tell them if you want a 50A circuit or a 60A circuit. They will pick the right wire size and breaker and will not do those kinds of hokey stupid tricks like I was having to warn against above.
But if you do want to learn more about it, here is where to start:
Ampacity Charts - Cerrowire

This table shows the wire gauge for various types of wire and how many amps they are allowed to run. That first column, that says "NM-B" is the stuff people refer to as Romex cable. It has multiple wires bundled together inside a rubber sheath. That is marked for a 60 degree C heat limit. That is for running directly inside insulated walls. The next column (75 degrees C) has the stuff that would be individual wires running inside a conduit, like along the outside surface of a wall. And you will notice that for a same wire gauge thickness, it does allow a higher current, because it is able to dissipate the heat better.

It's pretty straightforward if you just follow the limits.
So for a 50A circuit, you could do 6 gauge Romex or 8 gauge wires in conduit. Although, that's right at the 50A limit, so I would still recommend 6 gauge in that case too.
For a 60A circuit, you can see that it would be either 4 gauge Romex or 6 gauge wire in conduit.

Thanks for the info. I did see people talk about Romex cables so now I know what that is.

 

[Rocky_H]

Thanks for the info. I did see people talk about Romex cables so now I know what that is.

And I forgot to mention, but if you're wondering about the third column in that table with the 90 degrees C rating, you don't need to worry about those, because residential circuit breakers or outlets and Tesla wall connectors and such don't have their connection points rated to that temperature level, so the 60 or 75 columns are all that would be relevant for residential stuff.

 

[JCLee]

From the sounds of it the concern over the Ten 3 wall connector is a real issue. If the connector gets a little warm at 48amps then there probaly pushing it. I think I will stick with the 40 amp setting and breaker if I need more power I will change the breaker. I sort of feel it I need to charge it in a hurry then I need to be using a supercharger anyways.

Good decision. I installed a gen 3 WC myself and did the same thing after some research. 6/2 (or 6/3) NM-B is much easier to install, the wire is cheaper, and 50A circuit (40A charging) is plenty and better for the battery for long term. No need to worry about higher current/heat, etc.

 

[everydaychris]

Good decision. I installed a gen 3 WC myself and did the same thing after some research. 6/2 (or 6/3) NM-B is much easier to install, the wire is cheaper, and 50A circuit (40A charging) is plenty and better for the battery for long term. No need to worry about higher current/heat, etc.

Hmm..
I was going to still get a 60 amp because 50 is right at the limit as rocky points out. You can decrease the amps through the Tesla charger settings right?

 

[JCLee]

Hmm..
I was going to still get a 60 amp because 50 is right at the limit as rocky points out. You can decrease the amps through the Tesla charger settings right?

It's not safe and the extra charging speed is not worth. What would the insurance company say in case of fire?

 

[Pluturi]

It's not safe and the extra charging speed is not worth. What would the insurance company say in case of fire?

Please don't say things like this as it is completely wrong. If the circuit is installed as Rocky described above, it is perfectly safe and meets all of the electrical code requirements.

To answer the real question, yes, you can put in the circuit that is capable of 60A and run it at only 50A either by configuring the connector or the car. However, you are doing it for your own peace of mind. It will not help the battery by running at 50A vs. 60A. It really doesn't care.

 

[JCLee]

Please don't say things like this as it is completely wrong. If the circuit is installed as Rocky described above, it is perfectly safe and meets all of the electrical code requirements.

To answer the real question, yes, you can put in the circuit that is capable of 60A and run it at only 50A either by configuring the connector or the car. However, you are doing it for your own peace of mind. It will not help the battery by running at 50A vs. 60A. It really doesn't care.

No, I have to disagree with that. This is straight from the Tesla gen 3 WC manual (page 5).

If installing for maximum power, use minimum 6 AWG, 90° C-rated copper wire for conductors. NOTE: Upsize conductors if necessary.

Rocky might be right in that the copper conductor might not be the first point of failure because there are other components that don't meet the 90C rating, but still it is clearly described in the manual and violating it is entirely at the user's risk/fault.