14-50 and 50 amp breaker

[Insureit1]

I searched and was not able to find an answer to my specific questions. I have had the X for about a month now and had a Nissan LEAF prior. For three years charged the LEAF using an ESVE on a 40 amp breaker. This has been working fine with X but I would like to use the UMC so it is easier to plug and unplug the cable. The ESVE uses a 6-50 plug. when I installed the 6-50 plug I ran 3/3 AWG (?) wire and put in the 40 amp breaker. I am planning on changing the outlet to 14-50 tomorrow and will connect the currently unused neutral in the 14-50 outlet. So I have two questions.

1) Do I need to change the breaker to 50 amps or will the UMC work with a 40 amp breaker? If I keep the breaker at 40 amps do I need to change any setting on the X or will this happen automatically? I am fine with a 40 amp breaker and 20 mph charging and do not need the extra few miles a 50 amp breaker would provide.
2) If I move up to the 50 amp breaker the 3/3 awg wire will be sufficient, correct? I am pretty confident it will but want some reassurance. The wire says "3 awg with 10 awg ground". The ground is solid and the other wires are twisted. It has been almost 4 years since I put the wire in and have never had any issues at all. Thanks for any feedback!

 

[roblab]

1) Do I need to change the breaker to 50 amps or will the UMC work with a 40 amp breaker? If I keep the breaker at 40 amps do I need to change any setting on the X or will this happen automatically? I am fine with a 40 amp breaker and 20 mph charging and do not need the extra few miles a 50 amp breaker would provide.
2) If I move up to the 50 amp breaker the 3/3 awg wire will be sufficient, correct? I am pretty confident it will but want some reassurance. The wire says "3 awg with 10 awg ground". The ground is solid and the other wires are twisted.

I am sure other highly educated electrician types will answer this soon, but my question is that I have not seen 3 gauge wire. Which only means I don't know much. I would expect maybe 6, which would carry a 50 amp breaker. Also, you don't tell us how far the outlet is from the breaker, which matters.

You can wire the ground and neutral with the same wire. I don't think the UMC uses the ground anyway, but does use the neutral. Or the other way. Just make sure it's not touching, is shielded, etc.

If you use the UMC, the car gets a signal that says 40 amps. If you have a 40 amp breaker, that's too small, as your constant rate should be 80% of the circuit breaker. YOU will have to tell the car to charge at 32 amps. It would be safer to have a 50 amp breaker so you don't forget.

By way of interest, my 50 amp breaker and #6 wire evidently are showing some problem, because my car will only charge at 32 amps lately. I think Tesla made the car more conservative so there wouldn't be f***s in garages, and it doesn't like my setup. I'm having a real electrician check it out. But it charges fine at 32.

 

[Insureit1]

I am sure other highly educated electrician types will answer this soon, but my question is that I have not seen 3 gauge wire. Which only means I don't know much. I would expect maybe 6, which would carry a 50 amp breaker. Also, you don't tell us how far the outlet is from the breaker, which matters.

You can wire the ground and neutral with the same wire. I don't think the UMC uses the ground anyway, but does use the neutral. Or the other way. Just make sure it's not touching, is shielded, etc.

If you use the UMC, the car gets a signal that says 40 amps. If you have a 40 amp breaker, that's too small, as your constant rate should be 80% of the circuit breaker. YOU will have to tell the car to charge at 32 amps. It would be safer to have a 50 amp breaker so you don't forget.

By way of interest, my 50 amp breaker and #6 wire evidently are showing some problem, because my car will only charge at 32 amps lately. I think Tesla made the car more conservative so there wouldn't be f***s in garages, and it doesn't like my setup. I'm having a real electrician check it out. But it charges fine at 32.

Thanks for the info. This is a pretty thick set of wires and was hard as hell pulling thru the conduit. It definitely says "AWG 3 CU 3 CDR AWG 10 GROUND TYPE NN-B 600 VOL 75". Total run of wire is no more than 70 feet. Like I said everything works perfectly with the ESVE and 40 amp breaker. Just to be safe I am going to put in the 50 amp breaker.

 

[FlatSix911]

I am planning on changing the outlet to 14-50 tomorrow and will connect the currently unused neutral in the 14-50 outlet.
So I have two questions.
1) Do I need to change the breaker to 50 amps or will the UMC work with a 40 amp breaker? If I keep the breaker at 40 amps do I need to change any setting on the X or will this happen automatically? I am fine with a 40 amp breaker and 20 mph charging and do not need the extra few miles a 50 amp breaker would provide.

2) If I move up to the 50 amp breaker the 3/3 awg wire will be sufficient, correct? I am pretty confident it will but want some reassurance. The wire says "3 awg with 10 awg ground". The ground is solid and the other wires are twisted. It has been almost 4 years since I put the wire in and have never had any issues at all. Thanks for any feedback!

1. You should change the breaker to 50 Amps so you can charge at a full 40 Amp rate. See the table below:
2. Your wire gauge is oversized so you are able to install a HPWC if you need faster charging in the future.

 

[Insureit1]

Thanks guys. Changed out to a 50 amp breaker and everything is working. Charging shows 40A and 26 miles per hour charging rate. Everything looks good.

 

[Rocky_H]

Thanks guys. Changed out to a 50 amp breaker and everything is working. Charging shows 40A and 26 miles per hour charging rate. Everything looks good.

It's good that you did that, but I'll just throw in this detail of why it is actually an electric code requirement, as I have learned here from [whoops, drawing a blank on his name right now].

Normally a 50 amp outlet needs to have a 50A circuit with 50A breaker. You were using an exception case before. The exception is: There are 40A-specific appliances, like some ovens or your old EVSE. Since there are not 40A outlet types, they are allowed to use a 40A breaker with that 50A outlet type, like a 6-50, ONLY if it is being used with a 40A appliance. That was fine for your old wall unit. Now that you are going to be using the Tesla UMC, it is a 50A appliance, so the old 40A breaker is not allowed, and you have to get a 50A breaker that matches the device.

 

[number12]

Anyone use a leaf clipper creek charger with adapter on their tesla?

Does that just save not getting your own cord out and plugging into 240 plug?

 

[goneskiian]

It's good that you did that, but I'll just throw in this detail of why it is actually an electric code requirement, as I have learned here from [whoops, drawing a blank on his name right now].

Normally a 50 amp outlet needs to have a 50A circuit with 50A breaker. You were using an exception case before. The exception is: There are 40A-specific appliances, like some ovens or your old EVSE. Since there are not 40A outlet types, they are allowed to use a 40A breaker with that 50A outlet type, like a 6-50, ONLY if it is being used with a 40A appliance. That was fine for your old wall unit. Now that you are going to be using the Tesla UMC, it is a 50A appliance, so the old 40A breaker is not allowed, and you have to get a 50A breaker that matches the device.

@FlasherZ perhaps?

Anyone use a leaf clipper creek charger with adapter on their tesla?

Does that just save not getting your own cord out and plugging into 240 plug?

Yes, it's basically a J1772 head isn't it? It would work fine. You'd probably have to dial down the amps the Tesla pulls though.

 

[Insureit1]

Anyone use a leaf clipper creek charger with adapter on their tesla?

Does that just save not getting your own cord out and plugging into 240 plug?

I was using a Siemens VersiCharge ESVE and it worked fine and did not have to adjust anything on the X. What I did not like was the ESVE adapter and the J1772 required two hands to remove and almost always required me to put it in twice to get it to charge. I had the thicker wire already run and $15 for a new 50amp breaker and a 14-50 plug was easy to swap out and took less than 30 minutes. I just wanted the easier operation of the Tesla connector.

 

[Brass Guy]

I don't think you'd have to dial down the car. The car and EVSE negotiate and set the current. The problem arises when people (like me) use a home made adapter to plug into a lower current source. Without a proper Tesla adapter, the UMC tells the car 50A is OK.

 

[davewill]

Just one remark. The guy who said you could use the same wire for both the ground and neutral is dead wrong. I realize you didn't do this, but someone else reading the thread might take his advice.

 

[Insureit1]

Just one remark. The guy who said you could use the same wire for both the ground and neutral is dead wrong. I realize you didn't do this, but someone else reading the thread might take his advice.

Excellent point. On the 6-50 the neutral was not required or used. On the 14-50 you definitely need to connect the neutral AND make sure everything is connected properly. This is nothing to play around with.

 

[BerTX]

What keeps nagging me about this thread is that you used 3 guage wire in a 40 amp breaker. The 40 amp breakers I have used would not have a terminal big enough to fit that size wire. So either this is a different breaker type than I have used in my (admittedly limited) experience, or that is NOT 3 guage wire.

Like I said, it was just bothering me...

 

[Insureit1]

Definitely a 3 gauge wire based on the lettering on the wire. 40 amp and 50 amp breakers were both Square D breakers. Plenty of space for the wire to fit. You can see the red, black and white wire poking out in the middle of the picture. Everything seems to be working fine. Maybe there are differences between the ratings of wires I am not aware of.

 

[Brass Guy]

I'm no electrician, but that looks like #8 to me.

 

[CmdrThor]

I was using a Siemens VersiCharge ESVE and it worked fine and did not have to adjust anything on the X. What I did not like was the ESVE adapter and the J1772 required two hands to remove and almost always required me to put it in twice to get it to charge. I had the thicker wire already run and $15 for a new 50amp breaker and a 14-50 plug was easy to swap out and took less than 30 minutes. I just wanted the easier operation of the Tesla connector.

I also have a Siemens VersiCharge and it worked fine for charging my X, but its position in my garage was more suitable for the LEAF's charging port in the front of the car. To charge the X I had to drape the cable across the front of the car which was not ideal. We still have the LEAF so I kept the Siemens EVSE, but I added a Tesla Wall Connector in the back of the garage for the X. Hopefully someday I'll replace the LEAF with Model 3 and I can get another Wall Connector to replace the Siemens EVSE.

 

[CmdrThor]

I'm no electrician, but that looks like #8 to me.

Agree, I don't think #3 would come in NM-B like that. Plus it should have something like a #5 ground. Here is a picture of my #3 THHN for my Wall Connector install.

Also I used #8 NM-B for my 30 amp EVSE on a 40 amp breaker so that would make a lot of sense.

 

[davewill]

Yeah, when I search for nmb cable with a 10 awg ground, it's always got 8 awg conductors. 8 gauge is what was used for my 40a circuit. It's almost got to be some kind of misprint. I think the OP needs to take a hard look at this and be absolutely sure of the wire. If it is indeed 8 awg, he needs to back his install back down to a 40a breaker and 32a charging...or replace the wire.

 

[FlatSix911]

Yeah, when I search for nmb cable with a 10 awg ground, it's always got 8 awg conductors. 8 gauge is what was used for my 40a circuit. It's almost got to be some kind of misprint. I think the OP needs to take a hard look at this and be absolutely sure of the wire. If it is indeed 8 awg, he needs to back his install back down to a 40a breaker and 32a charging...or replace the wire.

Agree, however 8 AWG should be NEC rated for 40A charging.

 

[davewill]

Agree, however 8 AWG should be NEC rated for 40A charging.

According to the FAQ: Home Tesla charging infrastructure Q&A, using NM-B cable you need 6 AWG.