Home Wall Connector Install

[kppolich]

We recently moved to a new house and the Main Panel had plenty of room and a fairly short run to where I wanted to put a Wall Connector.

I was initially going to install a level 2 NEMA 14-50 Outlet and use my spare mobile charger, already purchased Homeline 50A GFCI breaker, and Hubbel 9450. However, I had purchased those items when we lived in an older home with a detached garage approximately 50 feet from the main panel. There, I had 2" underground conduit and purchased THHN wire in separate strands.

That initial thread is here:

Detached Garage, Conduit, 14-50, what else am I missing?

Currently wall charging my model 3 on 120V 12A and looking to add a Nema 14-50 plug. We are in Milwaukee, WI - 1950's house, detached garage ~40 feet away from main panel. Main Panel: 100A Service Garage: Load Center with (2) 15A circuits for receptacles & garage door opener. Now, the...

teslamotorsclub.com

However, we moved to a new house out of state and that never got used. Here we are today and below is a list of what I purchased and a few photos of the install process.

1.) Tesla Wall Connector (24') from the forums here - $315
2.) 30 feet of 6/3 Romex from Amazon - $120

Amazon.com

3.) Eaton 60A 2 Pole Breaker from Lowes - $20


I started by cracking open the panel to see what kind of shape it was in from the builder.
Woofta, what a beauty it was.

Then I ran the 6/3 to the access hole that was left by the builder and pushed it up into the wall.

Next, I measured over on the interior garage wall to the approximate height I wanted the Wall Connector. I knew where the access hole was below, so A simple 1" hole about 2" from the stud I was going to mount the Wall Connector on.
Voila! Grabbed it with a metal pick and pulled it though. I used a Oscillating Multitool to get a little larger hole to pull it through and also a place for the cable clamp to sit into the wall so the Connector body would be flush.

I put a wire nut on the white neutral and left it low and safe in the wall connector body in case we move or replace it with something that requires it. I ended up doing the same thing in the main panel, leaving a wire nut on the neutral white wire and running it long and safely tucking it away.

Here it is mounted, flush and I'm happy. I'l be doing a final drywall coat or two in the spring.


Back downstairs it was time to install the breaker and wire everything up.
Here you can see my neutral with the wire nut, tucked in ground and beginning of the wire organization process to match the original well done work.
View attachment 992774



Final Product, happy to be able to charge at 48A if needed. All in all, 30' was spot on. A little service loop left in the floor and only cutoff about a foot total doing the final trimming on each end.

Total cost: $455.00 USD
Total time: 3 hours

I ended up selling my Mobile Charger, Hubbel 9450A, 55' of THHN wire, and Homeline 50A GFCI for $500.00, so overall it was cheaper to go the wall connector route.

 

[brkaus]

6/3 nm-b isn’t rated for a 60a breaker.

 

[kppolich]

So I read a few things beforehand knowing 48A would be the max it would ever pull:

1.) NM-b works on 60 amp breaker if the operating load falls over 50 but not over 55 amps. If it falls on 56 amps you cannot use 6/3 G nm-b and a 60 amp breaker.

2.) 6/3 is normally protected with a 60-amp breaker. Since there are no 55-amp breakers, code allows you to round up to the next larger standard size.

3.) Per Manual - https://www.tesla.com/sites/default...ng/Gen3_WallConnector_Installation_Manual.pdf

• If installing for maximum power, use minimum 6 AWG, 90° C-rated copper wire for conductors.

Max load is 48A.


-Mostly this thread too

60A Breaker -> 4 gage or 6 gage wire?

I'm jumping on this thread, but I have to wonder why everyone is talking about, for the NM-B / Romex options, 4/3 or 6/3 instead of 4/2 or 6/2? You only need 2 power wires plus the ground wire. If you use 4/3, you are wasting one of the conductors and making the wire stiffer and harder to work...

teslamotorsclub.com

 

[Eric33432]

Beautiful wiring job on your panel, and nice job with the Tesla Wall Connector.

But . . . NM-B is rated for 60˚C which results in an ampaoity of 55 amps for non-continuous loads, and must be derated by 20% for continuous loads. Therefore NM-B is only allowed 80% of 55 amps because EVSE are considered continuous loads. That would be 44 amps, after derating.

Would I use NM-B? No I used 6/2 MC cable, rated for 75˚C and 65 amps. And I cannot say #6 NM-B is OK for 48 amp EVSE loads because I don't want any one to sue me for saying it is OK.

This video explains it. Pay attention to what he says at 3:04 into the video.

Lots of licensed electricians do exactly what you have done.

 

[kppolich]

Beautiful wiring job on your panel, and nice job with the Tesla Wall Connector.

But . . . NM-B is rated for 60˚C which results in an ampaoity of 55 amps for non-continuous loads, and must be derated by 20% for continuous loads. Therefore NM-B is only allowed 80% of 55 amps because EVSE are considered continuous loads. That would be 44 amps, after derating.

Would I use NM-B? No I used 6/2 MC cable, rated for 75˚C and 65 amps. And I cannot say #6 NM-B is OK for 48 amp EVSE loads because I don't want any one to sue me for saying it is OK.

This video explains it. Pay attention to what he says at 3:04 into the video.

Lots of licensed electricians do exactly what you have done.

So the wire I bought is temp rated for 90 C, does that change anything above?

 

[Eric33432]

So the wire I bought is temp rated for 90 C, does that change anything above?

Not if it is NM-B. NM-B is only rated for 60˚C and #6 NB-B is good for 55 amps non-continuous or 44 amps continuous. The 90˚C column is only used when derating the wire for ambient temperature.

 

[kppolich]

50A Breaker it is. Thanks team

 

[davewill]

Beautiful work! Don't sweat the 50a breaker. I think you'll find 40a charging entirely adequate.

 

[ATPMSD]

2.) 6/3 is normally protected with a 60-amp breaker. Since there are no 55-amp breakers, code allows you to round up to the next larger standard size.

Just for clarity, you can only use a 60a breaker with 55a wire if additional conditions are met:

1. One, and only one device will use the circuit
2. The device will not draw more than 55a. If you install a wall connector and set it to a 60a circuit you would be in violation of this rule.

So then, a 50a breaker is required and the wall connector must also be set to 50a.

 

[kppolich]

Thanks Team, 50A installed and adjusted on the Wall Connector too.

 

[SageBrush]

I would have used 6/2 instead of 6/3, but I think fair arguments can be made for either choice. In a recent EVSE install (for a GM Hummer EV of all things), we used 3/4" FMC with two #6 Cu and one #10 Cu for ground, good for a 60A circuit. That wiring + conduit scheme costs somewhere in the range of $2.5 - $3.5 a foot

 

[brkaus]

I would have used 6/2 instead of 6/3, but I think fair arguments can be made for either choice. In a recent EVSE install (for a GM Hummer EV of all things), we used 3/4" MC with two #6 Cu and one #10 Cu for ground, good for a 60A circuit

Super hard to get 6/2 NM-B. Makes MC more attractive.

But, using the 6/3 it's easy to replace the WC with a more universal 14-50 outlet. So if I'm pulling a wire I'd probably also pull a neutral (unless it's 100s of feet and really ran up the cost).

 

[SageBrush]

Super hard to get 6/2 NM-B

I hear you.

6/2 SEU can also be used. If run in walls with insulation, ampacity is the same as NM-B. If no insulation, I **think** you end up with an ampacity the same as conductors run in conduit

 

[Marc Connery]

I used 6/2 Romex with a 50 amp breaker over a 80 foot run - PITA but worth it.

 

[CMPT PAD]

We recently moved to a new house and the Main Panel had plenty of room and a fairly short run to where I wanted to put a Wall Connector.

I was initially going to install a level 2 NEMA 14-50 Outlet and use my spare mobile charger, already purchased Homeline 50A GFCI breaker, and Hubbel 9450. However, I had purchased those items when we lived in an older home with a detached garage approximately 50 feet from the main panel. There, I had 2" underground conduit and purchased THHN wire in separate strands.

That initial thread is here:

Detached Garage, Conduit, 14-50, what else am I missing?

Currently wall charging my model 3 on 120V 12A and looking to add a Nema 14-50 plug. We are in Milwaukee, WI - 1950's house, detached garage ~40 feet away from main panel. Main Panel: 100A Service Garage: Load Center with (2) 15A circuits for receptacles & garage door opener. Now, the...

teslamotorsclub.com

However, we moved to a new house out of state and that never got used. Here we are today and below is a list of what I purchased and a few photos of the install process.

1.) Tesla Wall Connector (24') from the forums here - $315
2.) 30 feet of 6/3 Romex from Amazon - $120

Amazon.com

3.) Eaton 60A 2 Pole Breaker from Lowes - $20


I started by cracking open the panel to see what kind of shape it was in from the builder.
Woofta, what a beauty it was.
View attachment 992780

Then I ran the 6/3 to the access hole that was left by the builder and pushed it up into the wall.

View attachment 992783View attachment 992790

Next, I measured over on the interior garage wall to the approximate height I wanted the Wall Connector. I knew where the access hole was below, so A simple 1" hole about 2" from the stud I was going to mount the Wall Connector on.
Voila! Grabbed it with a metal pick and pulled it though. I used a Oscillating Multitool to get a little larger hole to pull it through and also a place for the cable clamp to sit into the wall so the Connector body would be flush.
View attachment 992781

I put a wire nut on the white neutral and left it low and safe in the wall connector body in case we move or replace it with something that requires it. I ended up doing the same thing in the main panel, leaving a wire nut on the neutral white wire and running it long and safely tucking it away.
View attachment 992786View attachment 992787


Here it is mounted, flush and I'm happy. I'l be doing a final drywall coat or two in the spring.


Back downstairs it was time to install the breaker and wire everything up.
Here you can see my neutral with the wire nut, tucked in ground and beginning of the wire organization process to match the original well done work.
View attachment 992774



Final Product, happy to be able to charge at 48A if needed. All in all, 30' was spot on. A little service loop left in the floor and only cutoff about a foot total doing the final trimming on each end.
View attachment 992775View attachment 992789

Total cost: $455.00 USD
Total time: 3 hours

I ended up selling my Mobile Charger, Hubbel 9450A, 55' of THHN wire, and Homeline 50A GFCI for $500.00, so overall it was cheaper to go the wall connector route.

Beautiful job

 

[flixden]

Nice job! This is the cleanest install I have seen so far!

 

[tls]

I hear you.

6/2 SEU can also be used. If run in walls with insulation, ampacity is the same as NM-B. If no insulation, I **think** you end up with an ampacity the same as conductors run in conduit

Under 2017 and later code, SEU 8 gauge and larger uses the 75C ampacity even in insulated walls.

 

[Jerryr]

My electrician used 6-6-8 SEU copper cable connected and configured to 60 amps. SEU 6AWG COPPER Service entrance cable is good to 65 amps @ 75 deg C vs 55 amps for NM-B

 

[Danny Brown]

Just for clarity, you can only use a 60a breaker with 55a wire if additional conditions are met:

1. One, and only one device will use the circuit
2. The device will not draw more than 55a. If you install a wall connector and set it to a 60a circuit you would be in violation of this rule.

So then, a 50a breaker is required and the wall connector must also be set to 50a.

I’m genuinely curious… wouldn’t the OP be in compliance with both #1 and #2? (how does he violate #2 by pulling 48amps from the HPWC?)

 

[Tronguy]

I’m genuinely curious… wouldn’t the OP be in compliance with both #1 and #2? (how does he violate #2 by pulling 48amps from the HPWC?)

Sigh. It's all about the heat.

In the U.S. and Canada, the general idea is that transient loads up to the breaker capacity do warm up the wire, which then dissipates the heat by (in no particular order)

• Metal conduction of the heat towards the heat sinking ends of the wire
• Conduction of heat through any insulation material
• Radiative and convection transmission of the heat through any air gap (say, a wire in conduit)
• Conduction of heat through the conduit
• Conduction of heat through wood, house insulation, and what-all
• And, eventually, one gets to what is laughingly called the ambient, background temperature. "Laughingly" because the conduit/wire/whatever may be in an attic with no actual breeze passing by and elevated temperatures because of the sun beating on the roof.

This is all nasty to do in simulation (and, yeah, I've done some of that, but not with house wiring); my guess/understanding is that the UL, whoever it is that writes the NEC, and similar agencies build sample buildings in environmental chambers, attach thermocouples all over, and Make Measurements.

In the NEC realm of things, the general idea is that for continuous steady loads (that's charging a Tesla, for sure) that the maximum current run through the wires be no more than 80% of the circuit rating.

There's a point behind this: The concept of thermal mass. Just like with a car: Push down the accelerator pedal and, at T=0, the car isn't moving - it takes time to come up to speed. So, when one starts running a current through a wire, the power dissipation is there, but it's going to take time to heat the wire and all the surrounding thermal insulation.

So: Start an electric motor, say for a vacuum cleaner or the blower in the HVAC? At T=0, there's a honking big surge of current. Then the motor starts turning and, the faster it turns, the less current gets drawn. This is why almost all circuit breakers are labelled as, "slow blow" in one form or another. Here's a typical fuse curve from Littlefuse:

The curvy lines are for different amperage fuses. But note two interesting things:

• A 1A fuse curve (second from the left) can do 10A if the current pulse lasts a millisecond.
• That same fuse, when run for 100s, isn't going to blow. But run it for 10 minutes, and one will have a 50-50 chance that it will.

So, if one reads, "Fuseology" from Littlefuse (which, admittedly, is all about wired fuses, not breakers), one will discover:

• One never uses a fuse with a load current equal to the fuse's rating, unless it's a short pulse. (And there's all sorts of stuff about repetitive shots requiring derating of fuses, too.)
• Between manufacturing variations and avoiding nuisance blows, the maximum current through a fuse, steady state, shouldn't be more than 75% to 80% of the fuse's rating.

Thing is: A fuse goes blooey when it gets too hot.. just like wire will heat to the point of degrading the insulation around it. Actually, it's not that the wire melts, the melting temperature of copper or whatever is 'way the heck up there. It's when the insulation chars; or loses its flexibility and cracks; or starts conducting current after breaking down.

So, since it's all about temperature, what if one can, somehow, guarantee that the ambient temperature is cooler than what the NEC calls for?

I don't know. A whole buncha PhDs, safety experts, people with more math, thermocouples, and smarts whose intelligence I would hesitate to question say, "Don't use wire rated for 55A with a 60A breaker!".. And then we get $RANDOM people, some who are electricians, some who are not, who stare into the distance and say, "Sure. I figure it's not a problem because of X."

Are they going to guarantee your house won't burn down? If and when it does burn down, are they going to come by and, say, apologize?

If a bonded, licensed electrician comes by your house, does what passes for math, and it passes inspection, then, sure. You're paying them for the privilege. But if you're doing it on your own, do it in, "Better safe than sorry" mode and use the wire rated for 65A. Or use a 50A breaker. But don't use a 60A breaker with 55A rated wire.