Home Wall Connector Install

[SageBrush]

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?)

IF the wire ampacity is adequate for the load, THEN the breaker can be rounded up to the next standard size.

In the case we are talking about, a 48A continuous load requires a wire ampacity to be 1.25*48 = 60 Amps (or more). There are other environmental and installation variables that result in reduced wire ampacity, but I think the key point to grasp here is that the rounding up allowance for a breaker does not allow a wire to be used that is inadequate for the task.

 

[ATPMSD]

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?)

Seems odd, but it is a violation. Look at it this way, if we use 48a you multiple this by 125% to comply with the 80% “continuous load“ rule, which means the circuit must support a 60a intermittent load. And while the connector will not draw more than 48a, by setting the connector to 60a you are establishing a 60a circuit with wire than can only support 55a.

Bottom line, the electrical does not allow it.

 

[kimwin]

My observation: you connect the bare ground line from the panel to the Wall Connector. There is nothing wrong with this.
But many youtube videos (including Tesla's video) shows the white wire (usually means NEUTRAL) is used to connect ground in the panel to the ground spot in the Wall Connector (and one has to put a taped labelled GROUND, on this white wire . This is also correct.
I guess if you get a 6/2 cable, you got to use the bare ground wire instead.
I can only get the 6/3 cable and use the white wire for ground instead. The bare copper wire is cut really short, not connected, with wire nut in the panel.

 

[kppolich]

Can someone clear this up for me—
If the wire I had wasn’t in Romex and was in MC to would be fine?

The wire insulation is good to 90c, the romex sheath is the limiter at 60c which bumps down the amperage allowance in this case to 55a compared to 75a in MC?

 

[Eric33432]

Can someone clear this up for me—
If the wire I had wasn’t in Romex and was in MC to would be fine?

The wire insulation is good to 90c, the romex sheath is the limiter at 60c which bumps down the amperage allowance in this case to 55a compared to 75a in MC?

The answer to your question is "yes".

#6 NM-B cable is rated for 55 amps. When de-rated for continuous loads, it is only good for 44 amps.

#6 MC cable is rated for 65 amps (as is THHN/THWN-2 in conduit). When derated for continuous loads, it is good for 52 amps.

(90˚C insulation rating is only used for de-rating when running wire in hot environments or installing more than three current carrying conductors in a conduit. The terminals on the TWC and residential circuit breakers are only rated for 75˚C.)

If you ask "why", it is due to all the stuff that "Tronguy" discusses in is post above.

But just think about it for a minute. An intermittent load might heat the wire, but then the load shuts off and the wire has a chance to cool down, so it can handle more current than a Tesla Wall Connector, which might be drawing 48 amps for well over 3 hours.

The NEC has decided intermittent loads are loads that are on for less than 3 hours. These decisions are the result of years of experience, investigations of fires, testing, research, and so on.

And why can MC cable handle more current than NM-B? They both have the same wire contained in an outer sheath. Well, the metal sheath of MC cable can dissipate heat better than the plastic sheath of NM-B cable. And individual wires loosely contained in a conduit can dissipate heat better than the wires that are tightly contained inside the sheath of an NM-B cable.

If you overload a circuit a little, the insulation will not "melt" and will not suddenly burst into flames and burn your house down. Wiring is supposed to last for a long time. What happens is, over a long time the insulation becomes brittle and crusty, and it can crack and eventually two wires might start arcing which can, and does, cause fires.

I suspect the NEC code is conservative enough that a few percent of overload will not cause much trouble, but why not follow the code and do it right? The cost is not much more to do it right.

BTW, whoever installed your electrical panel did a beautiful job, and your installation of your TWC is also very nicely done.

NM-B (Romex) is used because it is easy to install. There is nothing wrong with it. But for installing a TWC that is going to run at 48 amps, with a 60 amp breaker, I think it is easier and better to use either conduit with THHN/THWN-2 wire, or MC cable. And #6 SE cable can also be used but it might be harder to get. MC is a little harder to work with, but easier than conduit if it has to be run where there would be a lot of bends or fished through existing walls. #4 NM is also sometimes hard to get, and very hard to bend in tight places like the TWC. And you have to buy 4-3 NM because 4/2 is not made by most manufacturers. MC cable might be hard to find at Lowes or Home Depot, but is easy to get from electric supply places or Amazon.

Hope this is helpful. Take care.

 

[rzn89]

I may be the only one to use UF 6/3 instead of times for my indoor nema 14-50. UF was half the price.

 

[SageBrush]

I may be the only one to use UF 6/3 instead of times for my indoor nema 14-50. UF was half the price.

And you lived to tell the tale. Impressive
I can barely run 12/2 UF and not scream

 

[Eric33432]

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?)

The thing to know is that you have to start with the ampacity of the circuit *before* applying any de-rating.

The NEC requires de-rating for certain installations for such things as temperature, number of wires in a conduit, and if the circuit is considered a continuous use (on for more than 3 hours) circuit. Ovens, ranges, and dryers, are not considered continuous use even if they are on more than 3 hours because they are thermostatically controlled and the heating elements are never on continuously.

If you use #6 NM-B, you start with a 55 amp circuit. You are allowed to install a 60 amp breaker because there are no 55 amp breakers available for most panels. That, however, does not magically make the circuit have a capacity of 60 amps.

So then you de-rate, (since the circuit is for an EVSE, and is a continuous use circuit) based on the ampacity of the circuit, which for #6 NM-B (commonly referred to as Romex) is 55 amps and you take 80% of 55 which is 44 amps.

If you want to learn more, watch the video in post #4 of this thread.

Hope this helps.

 

[Danny Brown]

Thanks to everyone for the replies. This is good to have here “for the record.” My question before in this thread was from reading those proposed 2 criteria too strictly.

I had this same consideration when I put in my HPWC Gen 3 a few years ago. Went with 6/2 NM-B and a 50 amp circuit breaker, and also configured HPWC for 50 amp breaker. I agree with what Will said earlier- hard to notice the difference between 240v charging at 48amp vs 44amp vs 40amp. (Especially since I was coming from 1yr/12k miles of NEMA 5-15 charging!)

 

[rzn89]

And you lived to tell the tale. Impressive
I can barely run 12/2 UF and not scream

It was terrible x1000! I snaked it through the ceiling in basement using a 6ft flexible drill bit and my stud finder to locate its exact spot in the garage wall. Stripping UF is horrid, If I ever need to run another 6/3 45ft I will use romex.

 

[rstx]

This is a pretty good solution here for 6/2 MC.

 

[TesLEEZ]

Here is a handy Amapacity Chart I printed out and keep handy: https://www.cerrowire.com/wp-content/uploads/2021/04/Cerrowire_Ampacity_Chart_210405.pdf

I also wired my garage with 6/3 NMB and a 50amp breaker. You're not missing anything, just a few minutes slower. The longest charge I've had was like 7-8 hours. For your families sake, better safe than sorry.

 

[gt40mkii]

Resurecting this thiread as it seems most appropriate.

I'm taking delivery of a MYLR tomorrow (My first EV!)

Short term plans arew to charge off the drier circuit using Tesla's mobile connector for about two weeks. I figure it will take me that long to install a dedicated 14-50 outlet in the garage.

So I wanted to see what you guys though of my hardware selections, given the above discussion of cables. My goal is to eventually either add or replace the 14-50 outlet with a Tesla wall connector.

• 40' 4/3 NM-B copper cable
• 60-Amp dual-pole breaker
• Bryant NEMA 14-50R outlet (same as Hubbell, but cheaper)
• 2-gang box
• Stainless Steel cover (fits Bryant outlet, which has a larger diameter.)

My main concern is the 4-gauge cable. The Bryant output will handle 4# wire, according to the Hubbell website. I still need to find a breaker that will handle 4# wire though. The Eaton BR260 I was going to use only goes up to 8#.

As for the cable itself, it will be run through an uninsulated attic for about 25'. I don't expect that attic to get over 70C (158F) in the summertime. Taking that and the fact that it shoudl be derated for continmuous use, would a 4# NM-B cable be ok on a 60A breaker (assuming I can find one.)

 

[gt40mkii]

Looks like a Cutler & Hammer CH260 will handle a 4# wire.

In other news, it looks like I need a disconnect switch too. This is the first I've heard of this, but CEC 86-304 reads:

86-304 Disconnecting means
(1) A separate disconnecting means for shall be provided for each installation of electric vehicle supply equipment rated at 60 A or more, or more than 150 volts-to-ground.
(2) The disconnecting means required in Subrule (1) shall be
(a) on the supply side of the point of connection of the electric vehicle supply equipment;
(b) located withing sight of and accessible to the electric vehicle supply equipment, and;
(c) capable of being locked in the open position.

Some are saying that putting in a breaker smaller than 60A avoids this requirement, but what about the 150 volts-to-ground stipulation? Seems that any 240V permanently wired equipment would need the disconnect, regardless of amperage.

 

[TesLEEZ]

Resurecting this thiread as it seems most appropriate.

I'm taking delivery of a MYLR tomorrow (My first EV!)

Short term plans arew to charge off the drier circuit using Tesla's mobile connector for about two weeks. I figure it will take me that long to install a dedicated 14-50 outlet in the garage.

So I wanted to see what you guys though of my hardware selections, given the above discussion of cables. My goal is to eventually either add or replace the 14-50 outlet with a Tesla wall connector.

• 40' 4/3 NM-B copper cable
• 60-Amp dual-pole breaker
• Bryant NEMA 14-50R outlet (same as Hubbell, but cheaper)
• 2-gang box
• Stainless Steel cover (fits Bryant outlet, which has a larger diameter.)

My main concern is the 4-gauge cable. The Bryant output will handle 4# wire, according to the Hubbell website. I still need to find a breaker that will handle 4# wire though. The Eaton BR260 I was going to use only goes up to 8#.

As for the cable itself, it will be run through an uninsulated attic for about 25'. I don't expect that attic to get over 70C (158F) in the summertime. Taking that and the fact that it shoudl be derated for continmuous use, would a 4# NM-B cable be ok on a 60A breaker (assuming I can find one.)

I installed 4/3 cable on a 14-50 Hubbel 9450 outlet on the other side of my garage next to the breaker. Since I only had to buy 5ft of wire, I used 4/3 MC cable instead of 6 guage. And I installed a Tesla wall charger on my main parking spot in the garage, but I used 6/2 wire since it was a much longer run.

Keep in mind, that even the Hubbel 9450 is only rated for 500 plug-in cycles. So it's best to plug it in and just leave the mobile charger on the wall. Don't put it back in your car everyday. That will wear out the contacts over time. The wire fits into the outlet just fine, and it fit into my Eaton(Cutlet Hammer) BR250 breaker just fine. Keep in mind, a 14-50 outlet is supposed to use a 50 amp breaker. You'll need to replace the breaker with a 60amp when you install the dedicated wall charger.

The problem with installing it was the 4 guage cable was really hard to bend and work with compared to 6 guage cable. The deep 2 gang box I bought was not deep enough. Lowes and Home Depot did not have deep enough boxes. So I ordered this one on Amazon and waited 2 days to finish the install. If your wall stud is 2x4, it will stick out as this is 3.5inches deep: Amazon.com But it made for a much easier install with 4 guage cable. I ended up surface mounting it.

If your state uses NEC 2020 electrical code, technically you're supposed to use a GFCI breaker which is $100+ with your 14-50 outlet. GFCI outlets also cause issues with some EV chargers. Luckily my state is still on NEC 2017 so I didn't need to do that. But if you have to use a GFCI breaker, the cost of a 14-50 outlet is halfway to a wall charger. Wall chargers do not require a GFCI breaker, only outlets.

After installing both, if I had to do it again, I would install a Tesla Wall charger every time. It wires in so much easier than a 14-50 outlet. It's safer because the wall charger has a temp sensor on the PCB which monitors the wire temperature at the connection point. It'll automatically turn off if it's too hot.

Here's a state map with NEC codes:

 

[brkaus]

(1) A separate disconnecting means for shall be provided for each installation of electric vehicle supply equipment rated at 60 A or more, or more than 150 volts-to-ground.

Yes, you're correct for a 60A circuit. A 50A doesn't need it though because a 240v household circuit is 120v each leg to ground. What we have is split phase 120v.

Also, you mention a 60A breaker on a 14-50 outlet. That's not a good idea at all (nor would it be legal).

 

[TesLEEZ]

Yes, you're correct for a 60A circuit. A 50A doesn't need it though because a 240v household circuit is 120v each leg to ground. What we have is split phase 120v.

Also, you mention a 60A breaker on a 14-50 outlet. That's not a good idea at all (nor would it be legal).

Yep, if you use a multimeter with one probe in the ground hole, you'll only see 120v to any other pin. You'll only see 240v with respect to each other, not ground.

I'd stick with 6 guage wire for the wall charger and a 50 amp breaker. You're not losing out on anything, the extra 8 amps won't charge that much faster.

 

[Supcom]

Resurecting this thiread as it seems most appropriate.

I'm taking delivery of a MYLR tomorrow (My first EV!)

Short term plans arew to charge off the drier circuit using Tesla's mobile connector for about two weeks. I figure it will take me that long to install a dedicated 14-50 outlet in the garage.

So I wanted to see what you guys though of my hardware selections, given the above discussion of cables. My goal is to eventually either add or replace the 14-50 outlet with a Tesla wall connector.

• 40' 4/3 NM-B copper cable
• 60-Amp dual-pole breaker
• Bryant NEMA 14-50R outlet (same as Hubbell, but cheaper)
• 2-gang box
• Stainless Steel cover (fits Bryant outlet, which has a larger diameter.)

My main concern is the 4-gauge cable. The Bryant output will handle 4# wire, according to the Hubbell website. I still need to find a breaker that will handle 4# wire though. The Eaton BR260 I was going to use only goes up to 8#.

As for the cable itself, it will be run through an uninsulated attic for about 25'. I don't expect that attic to get over 70C (158F) in the summertime. Taking that and the fact that it shoudl be derated for continmuous use, would a 4# NM-B cable be ok on a 60A breaker (assuming I can find one.)

My recommendation is to skip the 14-50 outlet and install the wall connector from the get go. You'll get faster charging with no potential outlet issues. Using a 50A breaker should allow you to get by with smaller (cheaper) wire yet still permit 40A charging, which should be sufficient for most home charging.

I also suggest getting a bid from a licensed electrician. Even if you decide to do the job yourself, talking to the electrician might alert you to any code issues (national or local) that you should know.

 

[kppolich]

Resurecting this thiread as it seems most appropriate.

I'm taking delivery of a MYLR tomorrow (My first EV!)

Short term plans arew to charge off the drier circuit using Tesla's mobile connector for about two weeks. I figure it will take me that long to install a dedicated 14-50 outlet in the garage.

So I wanted to see what you guys though of my hardware selections, given the above discussion of cables. My goal is to eventually either add or replace the 14-50 outlet with a Tesla wall connector.

• 40' 4/3 NM-B copper cable
• 60-Amp dual-pole breaker
• Bryant NEMA 14-50R outlet (same as Hubbell, but cheaper)
• 2-gang box
• Stainless Steel cover (fits Bryant outlet, which has a larger diameter.)

My main concern is the 4-gauge cable. The Bryant output will handle 4# wire, according to the Hubbell website. I still need to find a breaker that will handle 4# wire though. The Eaton BR260 I was going to use only goes up to 8#.

As for the cable itself, it will be run through an uninsulated attic for about 25'. I don't expect that attic to get over 70C (158F) in the summertime. Taking that and the fact that it shoudl be derated for continmuous use, would a 4# NM-B cable be ok on a 60A breaker (assuming I can find one.)

If you are using the mobile connector for level 2 and the 14-50 you'll need a GFCI breaker.
I have a 50A Homeline Square D for sale if you are interested.

FS: Square D Homeline HOM250GFIC 50 Amp 2-Pole GFCI Circuit Breaker

Mobile charger sold. Hubbel SOLD Square D Homeline HOM250GFIC 50 Amp 2-Pole GFCI Circuit Breaker for sale. We moved before I had a chance to install these and I'm now going with a Tesla Wall Connector. 2.) Square D Homeline HOM250GFIC 50 Amp 2-Pole...

teslamotorsclub.com

However, as the OP of this thread and someone who went down the same path, it's cheaper and faster charging to leave the mobile connector in your car and install a wall connector.

Check the classifies here, they are available all the time for $300-350 shipped.

Your shopping list for the Wall Connector should include:
60A Dual Pole
6/3 or 6/2 MC wire or 4/3 Romex.
Wall Connector

Your shopping list for dedicated 14-50 would include:
14-50 receptacle
GFCI breaker (50A)
Old/New Work Box
Cover Plate
Wire(6ga MC if you would ever replace with a Wall Connector) or 4/3 Romex.
If staying with 14/50, 6/3 would be the choice.

 

[Tronguy]

I'm going to chime in with other posters here: If you're going to install wire, GFCIs, a non-junk NEMA14-50, and have to buy a Mobile Connector to charge the car (Mobile Connectors are Extra these days) it'll be far cheaper and a bit faster charging to just get a Wall Connector. You can then pay a bit more for 65A wire (there's no 60A wire - it's 55A, or 65A), the right circuit breaker, and $450 to Tesla for the Tesla Wall Connector. No GFCI required.

In addition, on another thread, it was pointed out that there's another company making Wall Connectors out in Colorado. It also does 48A and costs $400 on Amazon.