Gen 3 Wall Connector Installation Advice

[ghsnick!]

When I built my home I had the builder install a 50A GFCI Breaker and wiring to the outside for a Gen 3 Tesla Charger.

Here’s a picture of the box and where I want the Tesla charger mounted.

I opened the box and noticed it was a bit wet inside (sprinkler was hitting it, I fixed that) and there was some rust inside.

I believe the electrician is going to use that as a “junction box” or sorts and run some new wire (with conduit) so I can mount it exactly where I want to. He will probably enter the Tesla Charger like the second picture shows for “Bottom Entry” from the junction box.

1. Is it still considered a hard wire connection if the wires are connected/extended from the junction box?

2. Is there a way to limit the charger to 40A since I’m only on a 50A breaker/wiring?

3. Is it a good idea to remove the 50A GFCI Breaker and install a 50A Breaker?

I’m mounting this outside…has anyone had issues with the charger/junction box (for those that have one) getting wet and causing issues?

Any other advice / ideas are recommended!

 

[Cosmacelf]

Yes, yes and yes. I’d get a new cover for that box, but after that you should be good.

 

[archae86]

2. Is there a way to limit the charger to 40A since I’m only on a 50A breaker/wiring?

That is the easy one. A standard step in commissioning this generation Wall Connector involves telling the connector what rating circuit breaker it is on. The available choices are 60, 50, 40, 30, 20, and 15A, and limits itself to 80% of that value.

I found the commissioning procedure to be baffling in behavior--but the setting and limiting you want are right there.

 

[Awiner]

Tesla specifies not to use a GFCI breaker on the circuit the wall connector is wired to. The reason is because the wall connnecter has a internal GFCI.

 

[ghsnick!]

Yes, yes and yes. I’d get a new cover for that box, but after that you should be good.

That is the easy one. A standard step in commissioning this generation Wall Connector involves telling the connector what rating circuit breaker it is on. The available choices are 60, 50, 40, 30, 20, and 15A, and limits itself to 80% of that value.

I found the commissioning procedure to be baffling in behavior--but the setting and limiting you want are right there.

Tesla specifies not to use a GFCI breaker on the circuit the wall connector is wired to. The reason is because the wall connnecter has an internal GFCI.

Thanks for the feedback! Now I realized there’s #6 Romex and a 50A GFCI Breaker.

I plan on switching the breaker to a revaluation Non GFCI Breaker, but on #6 Romex couldn’t I upgrade to a 60A Breaker? I’m fine doing 50A and limiting the charge to 40A, but if it’s wired for #6 and I can do more, why not?

And any advice on a new cover box? Or one that won’t leak anymore?

 

[Cosmacelf]

Thanks for the feedback! Now I realized there’s #6 Romex and a 50A GFCI Breaker.

I plan on switching the breaker to a revaluation Non GFCI Breaker, but on #6 Romex couldn’t I upgrade to a 60A Breaker? I’m fine doing 50A and limiting the charge to 40A, but if it’s wired for #6 and I can do more, why not?

And any advice on a new cover box? Or one that won’t leak anymore?

Nope, #6 romex is only rated for 55A. So, by code, you should be using a 50A breaker and charging at 40A. It is very rare to find a household appliance that needs 60A, so electricians just default to #6 romex for all heavy duty electrical appliances. They haven’t been trained/don’t know that the newer crop of EVSEs can use 60A if available.

Just get the same cover for that box, but a new one, that’s all. The rust doesn’t hurt anything and could be caused by dew as much as anything.

 

[Rocky_H]

but on #6 Romex couldn’t I upgrade to a 60A Breaker? I’m fine doing 50A and limiting the charge to 40A, but if it’s wired for #6 and I can do more, why not?

No, it definitely can't. You can see the ratings in this table.

Cerrowire Resources - Ampacity Charts

Ampacity is the maximum current that a conductor can carry continuously under the conditions of use without exceeding its temperature rating. Cerrowire's ampacity chart helps calculate the load requirement for a circuit.

www.cerrowire.com

Romex is NM-B, and it's in that first column of 60 degrees C. It is only rated up to 55A circuit ratings, not 60. If it were 6 gauge individual wires in conduit, that is the stuff in the 75 degree column and has a 65 degrees C rating, so that could be used for a 60A circuit.

 

[davewill]

It doesn't help that the Tesla wall connector installation instructions don't more clearly specify the wire that should be used. It just says, "If installing for maximum power, use minimum 6 AWG, 90° C-rated copper wire for conductors." and it seems a lot of people stop reading after "6 AWG".

 

[Rocky_H]

It just says, "If installing for maximum power, use minimum 6 AWG, 90° C-rated copper wire for conductors." and it seems a lot of people stop reading after "6 AWG".

That statement makes it all worse and much more confusing, because it is saying nothing! Almost all kinds of wire you can get in any configuration already use 90 degree rated insulation! That's standard in everything. Even the conductors inside Romex are using 90 degree insulation. But they are bundled together in that sheath, which makes them have to use the lower 60 degree rating. So that dumb statement by Tesla doesn't add any useful information and only gets incorrect ideas and assumptions into people's heads.

It doesn't help that the Tesla wall connector installation instructions don't more clearly specify the wire that should be used.

I think it should go in the opposite direction. Tesla should not be trying to get really specific with telling people what to use. It should be left more general, to say, "Follow NEC guidelines for the type and gauge of wire for the amp rating of circuit you choose." Then, they may choose armored cable or THHN or tray cable or whatever fits their location and use case.

 

[davewill]

I think it should go in the opposite direction. Tesla should not be trying to get really specific with telling people what to use. It should be left more general, to say, "Follow NEC guidelines for the type and gauge of wire for the amp rating of circuit you choose." Then, they may choose armored cable or THHN or tray cable or whatever fits their location and use case.

That might be best for Tesla's liability exposure and guard against future building code changes, but giving specific guidance is the only way this situation of a large number of erroneous installs would ever improve.

 

[ghsnick!]

Nope, #6 romex is only rated for 55A. So, by code, you should be using a 50A breaker and charging at 40A. It is very rare to find a household appliance that needs 60A, so electricians just default to #6 romex for all heavy duty electrical appliances. They haven’t been trained/don’t know that the newer crop of EVSEs can use 60A if available.

Just get the same cover for that box, but a new one, that’s all. The rust doesn’t hurt anything and could be caused by dew as much as anything.

No, it definitely can't. You can see the ratings in this table.

Cerrowire Resources - Ampacity Charts

Ampacity is the maximum current that a conductor can carry continuously under the conditions of use without exceeding its temperature rating. Cerrowire's ampacity chart helps calculate the load requirement for a circuit.

www.cerrowire.com

Romex is NM-B, and it's in that first column of 60 degrees C. It is only rated up to 55A circuit ratings, not 60. If it were 6 gauge individual wires in conduit, that is the stuff in the 75 degree column and has a 65 degrees C rating, so that could be used for a 60A circuit.

It doesn't help that the Tesla wall connector installation instructions don't more clearly specify the wire that should be used. It just says, "If installing for maximum power, use minimum 6 AWG, 90° C-rated copper wire for conductors." and it seems a lot of people stop reading after "6 AWG".

Since I have #6 Romex to my junction box, I was told I had to put it on a 50A breaker (and the charger could pull 40A).

What’s weird…and please confirm if this is correct, is at the junction box with the Romex, they connected #8 THHN for the two black wires and #10 THHN for the ground wire. Does that sound right since I’m on a 50A breaker?

 

[Cosmacelf]

Since I have #6 Romex to my junction box, I was told I had to put it on a 50A breaker (and the charger could pull 40A).

What’s weird…and please confirm if this is correct, is at the junction box with the Romex, they connected #8 THHN for the two black wires and #10 THHN for the ground wire. Does that sound right since I’m on a 50A breaker?

Yes, that’s to code. It is correct for a 50A breaker. I’ve got an abbreviated chart on this page showing this. CarCharging.us

Basically Romex (NM-B) can’t handle as much current as THHN in a conduit.

 

[Rocket_man]

Thanks for the feedback! Now I realized there’s #6 Romex and a 50A GFCI Breaker.

I plan on switching the breaker to a revaluation Non GFCI Breaker, but on #6 Romex couldn’t I upgrade to a 60A Breaker? I’m fine doing 50A and limiting the charge to 40A, but if it’s wired for #6 and I can do more, why not?

And any advice on a new cover box? Or one that won’t leak anymore?

The other consideration is the max capacity of your house service. There is a calculation that you can do to model your panel capacity, the size of the house, large appliances etc and it will tell you what size service you need.... 100 amps, 150 amps, 175, 200 etc. There is an app called Mike Holts Electrical Toolbox that may be helpful. I have 150 amp service, and decently large house, two A/C units, and electric clothes dryer, oven, microwave, and induction cooktop. I don't think my service could take an extra 60-amp breaker. I mounted mine inside my garage using #6 90 deg Romex on a 50-amp non-GFCI breaker. I set the limit in the Wall Charger to 32 amps since I have a Model 3 RWD and it can't take more than that anyway. Even if I could get to 40-amps it wouldn't do me much good if I'm charging over night. I can get there just fine at 32 amps.. actually even 26 amps works just fine.

You might consider a PVC junction box with PVC water proof conduit so close to that hose bib.

 

[CKwik240]

I have 150 amp service, and decently large house, two A/C units, and electric clothes dryer, oven, microwave, and induction cooktop. I don't think my service could take an extra 60-amp breaker.

How many of those devices are you using when you charge. Or could you charge at night instead when you're not using those and use 60 amps? Assume your car could charge at that rate for this thought exercise.

 

[Rocket_man]

How many of those devices are you using when you charge. Or could you charge at night instead when you're not using those and use 60 amps? Assume your car could charge at that rate for this thought exercise.

Sure _I_ could manage the instantaneous load, but my wife can't/won't. And most homeowners also can't/wont. How many folks know the power draw of their clothes dryer? Mine is 7kw on a 'Normal' setting. That is nearly the draw of charging my car. So these rules of thumb of how many breakers of a certain size can be in your panel is meant to avoid tripping the main breaker. Only so many lights, appliances, air conditioners are going to be running at any given time, or at max times of the day like when people come home from work, crank up the AC, make dinner, do laundry etc. My Panel is about maxed out given these rules of thumb, but I have empty spots in a sub panel and could probably add some circuits that are not often used and/or high power draw. When both A/C units are running (which is often during the summer in TX) and the clothes dryer is running, that is nearly 15kw of power draw alone. The house takes about 1kw when the lights are on. That still gives me a lot of headroom on a 150amp panel. But add the car and the oven and I might be pretty close.

 

[CKwik240]

Sure _I_ could manage the instantaneous load, but my wife can't/won't. And most homeowners also can't/wont. How many folks know the power draw of their clothes dryer? Mine is 7kw on a 'Normal' setting. That is nearly the draw of charging my car. So these rules of thumb of how many breakers of a certain size can be in your panel is meant to avoid tripping the main breaker. Only so many lights, appliances, air conditioners are going to be running at any given time, or at max times of the day like when people come home from work, crank up the AC, make dinner, do laundry etc. My Panel is about maxed out given these rules of thumb, but I have empty spots in a sub panel and could probably add some circuits that are not often used and/or high power draw. When both A/C units are running (which is often during the summer in TX) and the clothes dryer is running, that is nearly 15kw of power draw alone. The house takes about 1kw when the lights are on. That still gives me a lot of headroom on a 150amp panel. But add the car and the oven and I might be pretty close.

Not sure if your charging needs, but if you don't actually need to charge often during the day, it would seem like charging while you sleep could be an option, especially if you're charging at 48A. Scheduling the car to charge after bedtime seems easy enough. I can see the possibility of running AC at night, but the oven AND the dryer?

As an aside, 1kW for lighting seems high. Especially if they are all LEDs. Assuming 6W lights, that's 166 lights. Lol.

 

[Rocket_man]

Not sure if your charging needs, but if you don't actually need to charge often during the day, it would seem like charging while you sleep could be an option, especially if you're charging at 48A. Scheduling the car to charge after bedtime seems easy enough. I can see the possibility of running AC at night, but the oven AND the dryer?

As an aside, 1kW for lighting seems high. Especially if they are all LEDs. Assuming 6W lights, that's 166 lights. Lol.

Honestly I don't have a problem. I was just responding to the OP's question. But to answer the other questions..... I have solar and yes I can charge at night and often do, but sometimes I like to charge on a sunny day just for the heck of it to see if I can get the house batteries and the car battery both to 100%. I don't need to, it is just somehow satisfying. I have a Sense house monitor and I can see the loads at any given time on the house. What I meant by the 1kw comment is that when the house is occupied (without any AC or major appliances running) it draws about 1kw. This is things like lights (all LEDs) but also TV's, the fridge, some air filters, IT equipment, other phantom loads. When I leave and turn the lights off it goes down to about 800 watts. A lot more than I thought it would be, but I'm reading this right from the main power feed on the house. As I type this late at night, some lights are off, the house is drawing 890 watts. A TV is on, living room lights, IT systems, air filters, outside lights... it adds up. Just now the draw went up to 930 watts, could be the fridge kicking on. The loads are constantly changing but it takes about 1kw just to occupy the house.

Here is the last ~30 minutes of data...

 

[CKwik240]

Honestly I don't have a problem. I was just responding to the OP's question. But to answer the other questions..... I have solar and yes I can charge at night and often do, but sometimes I like to charge on a sunny day just for the heck of it to see if I can get the house batteries and the car battery both to 100%. I don't need to, it is just somehow satisfying. I have a Sense house monitor and I can see the loads at any given time on the house. What I meant by the 1kw comment is that when the house is occupied (without any AC or major appliances running) it draws about 1kw. This is things like lights (all LEDs) but also TV's, the fridge, some air filters, IT equipment, other phantom loads. When I leave and turn the lights off it goes down to about 800 watts. A lot more than I thought it would be, but I'm reading this right from the main power feed on the house. As I type this late at night, some lights are off, the house is drawing 890 watts. A TV is on, living room lights, IT systems, air filters, outside lights... it adds up. Just now the draw went up to 930 watts, could be the fridge kicking on. The loads are constantly changing but it takes about 1kw just to occupy the house.

Here is the last ~30 minutes of data...

View attachment 920458

Gotcha. 1kW for only lights would be a lot.

 

[ghsnick!]

Yes, that’s to code. It is correct for a 50A breaker. I’ve got an abbreviated chart on this page showing this. CarCharging.us

Basically Romex (NM-B) can’t handle as much current as THHN in a conduit.

The other consideration is the max capacity of your house service. There is a calculation that you can do to model your panel capacity, the size of the house, large appliances etc and it will tell you what size service you need.... 100 amps, 150 amps, 175, 200 etc. There is an app called Mike Holts Electrical Toolbox that may be helpful. I have 150 amp service, and decently large house, two A/C units, and electric clothes dryer, oven, microwave, and induction cooktop. I don't think my service could take an extra 60-amp breaker. I mounted mine inside my garage using #6 90 deg Romex on a 50-amp non-GFCI breaker. I set the limit in the Wall Charger to 32 amps since I have a Model 3 RWD and it can't take more than that anyway. Even if I could get to 40-amps it wouldn't do me much good if I'm charging over night. I can get there just fine at 32 amps.. actually even 26 amps works just fine.

You might consider a PVC junction box with PVC water proof conduit so close to that hose bib.

To confirm - the power is off to this charger.

I noticed some of the wires are split to the sides of the tightening screw.

I thought all the strands of the wire needed to make good contact and noticed there’s gaps on the sides where some strands went.

This can easily be fixed while open (and the power is off). Should it be loosened so the wires can be clumped together and tightened? Or just leave it as is?

 

[Sophias_dad]

To confirm - the power is off to this charger.

I noticed some of the wires are split to the sides of the tightening screw.

I thought all the strands of the wire needed to make good contact and noticed there’s gaps on the sides where some strands went.

View attachment 920610View attachment 920611

This can easily be fixed while open (and the power is off). Should it be loosened so the wires can be clumped together and tightened? Or just leave it as is?

TBH, I'd leave it as is. Another attempt will probably result in exactly the same outcome.

If I were installing this new, I'd use ferrules to tightly hold the strands together. In fact, that's what I did.