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

[Rocky_H]

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 with than necessary.

Yeah, I've wondered why this is so common too, but it's possibly just for what wire you can get easily or to prepare swapping over to a 14-50 outlet if people move and take the wall connector. But your follow up question would be, "Why don't people just put a 6-50 outlet on it then if it doesn't have the neutral?" Yes, that's certainly possible, but a lot of people think a 14-50 is more common/wanted/useful.

But for a 14-50 socket, I think it's wired differently and can't be used for a normal 14-50 application anyway?

No, the installation of a NEMA 14-50 outlet is a defined specification. You just say that's the outlet type you want, and the electrician knows how it's supposed to be done. It's not different for use by an EV or by anything else. That wouldn't make sense anyway, because Tesla picked that because campgrounds across the country already have those, so it was a pre-existing ad-hoc charging network for traveling before they had to build anything.

 

[tga]

Sure, I was thinking of the case where the next owner of the dwelling has a non-Tesla EV and requires a 14-50 socket (with Neutral) for their charge cord.

What non-Tesla EV requires (or even can use) a 14-50?

 

[mongo]

What non-Tesla EV requires (or even can use) a 14-50?

I have no clue. Hopefully in the future when they sell the house there is at least one car that can charge that fast or else the 40A ClipperCreek EVSE with 14-50 plug is just a waste...
40A Level 2 EVSE HCS-50P with NEMA 14-50 | ClipperCreek

 

[Ritz]

What non-Tesla EV requires (or even can use) a 14-50?

No idea, but when I'm not using mine to charge the car, I can use it for my large air compressor or my MIG welder.

 

[tga]

I have no clue. Hopefully in the future when they sell the house there is at least one car that can charge that fast or else the 40A ClipperCreek EVSE with 14-50 plug is just a waste...
40A Level 2 EVSE HCS-50P with NEMA 14-50 | ClipperCreek

Any Clipper Creek (including the HCS-50P) available with a 14-50 is also available with a 6-50, for the same price.

No idea, but when I'm not using mine to charge the car, I can use it for my large air compressor or my MIG welder.

But your compressor and MIG don't need the neutral. Your MIG probably came with a 6-50, anyway (my Lincoln did).

No matter how you slice it, running a neutral to a wall connector is just a waste of copper...

 

[Ritz]

Any Clipper Creek (including the HCS-50P) available with a 14-50 is also available with a 6-50, for the same price.

But your compressor and MIG don't need the neutral. Your MIG probably came with a 6-50, anyway (my Lincoln did).

No matter how you slice it, running a neutral to a wall connector is just a waste of copper...

I use this adapter for my welder.

https://www.amazon.com/ONETAK-Welding-Charger-Connector-Connecter/dp/B07M5CBXJW

I wasn't commenting on "the waste" as you put it....merely on what else I use that receptacle for when it isn't being used by the car.

Best,

 

[Rocky_H]

What non-Tesla EV requires (or even can use) a 14-50?

When I didn't think there were any others, people pointedly told me about a couple. Apparently the newer 2018 and onward Nissan Leaf and the Audi e-Tron do come with charge cords that have 14-50 plugs on them.

NEMA 14-50 is dead - all hail NEMA 6-50

 

[NINJ3RK]

Guys, why not just run #2 AL SER cable??

 

[NINJ3RK]

NVM... I see why. There is a solution, however. You can use dual rated mechanical splices to #6 THHN2 in the enclosures at each end (60A breaker and Tesla wall Connector . Rubber tape, super 33 layer and heat shrink over the splices. You'd save a buttload on the wire, and it's relatively easy to run/work with.

 

[mswlogo]

Guys, why not just run #2 AL SER cable??

I always try to avoid AL. So much harder to work with. But when it gets to big of a load you have no choice.

 

[Ritz]

I don't know why some people are interested in skimping here. Unlike most electrical loads in your home, your car is going to draw a significant load for hours at a time. Feel the temperature of that power whip to your car the next time it's been charging for a little while. That circuit is not really where I'd be looking to save a few dollars.

 

[Ejl80]

I don't know why some people are interested in skimping here. Unlike most electrical loads in your home, your car is going to draw a significant load for hours at a time. Feel the temperature of that power whip to your car the next time it's been charging for a little while. That circuit is not really where I'd be looking to save a few dollars.

It is interesting that people are willing to pay hundreds to change the color of the trim on their car (me included), but are upset at a few hundred for a safe wiring run in their home.

 

[Vines]

Wish i could change my post #44 to remove the AL option. I misspoke and was schooled later in the thread. HPWC aren't rated for Al wire.

Maybe a mod will help?

 

[All In]

Any recommendations on where to find 4/3 or 4/2 romex? 6/3 and 6/2 look redily available at your standard Home Depot and Lowes, but I'm only seeing 4 gauge in THHN.

 

[mongo]

Any recommendations on where to find 4/3 or 4/2 romex? 6/3 and 6/2 look redily available at your standard Home Depot and Lowes, but I'm only seeing 4 gauge in THHN.

One source:
NM-B Wire (Romex® Equivalents) | Wire & Cable Your Way

 

[sunbear]

Came here to say essentially the same thing as eprosenx did. I'll just add the NEC code sections to back up his claims about why Contractor #1 is wrong.

NEC 210.20(A) Specifies that overcurrent protection devices "shall be sized to not less than the noncontinuous load plus 125 percent of the continuous load." This is the part we all know about for picking our breaker size.

NEC 210.19(A)(1) "...minimum branch-circuit conductor size...shall have an allowable ampacity not less than the noncontinuous load plus 125 percent of the continuous load."

Since these are single device circuits, there is no noncontinuous load, just the Wall connector which is by code a continuous load.

Does any of the advice on appropriate tesla charger wire sizing change as a result of the 2020 updates to the code here?

210.19(A)(1) Branch Circuits.

Installing 90°C rated power distribution blocks and a gutter at each end of a long run of branch circuit conductors just before terminating them in the panelboard or load equipment at each end can create an allowance where smaller size 90°C rated wire can be run between gutter boxes.

www.electricallicenserenewal.com

210.19(A)(1) General. Branch-circuit conductors shall have an ampacity not less than the larger of 210.19(A)(1)(a) or (A)(1)(b) and comply with 110.14(C) for equipment terminations.

(a) Where a branch circuit supplies continuous loads or any combination of continuous and noncontinuous loads, the minimum branch-circuit conductor size shall have an ampacity not less than the noncontinuous load plus 125 percent of the continuous load in accordance with 310.14.

(b) The minimum branch-circuit conductor size shall have an ampacity not less than the maximum load to be served after the application of any adjustment or correction factors in accordance with 310.15.

Exception No. 1 to (1)(a): If the assembly, including the overcurrent devices protecting the branch circuit(s), is listed for operation at 100 percent of its rating, the ampacity of the branch-circuit conductors shall be permitted to be not less than the sum of the continuous load plus the noncontinuous load in accordance with 110.14(C).

Exception No. 2 to (1)(a) and (1)(b): Where a portion of a branch circuit is connected at both its supply and load ends to separately instal⁠led pressure connections as covered in 110.14(C)(2), it shall be permitted to have an allowable ampacity, in accordance with 310.15, not less than the sum of the continuous load plus the noncontinuous load. No portion of a branch circuit installed under this exception shall extend into an enclosure containing either the branch-circuit supply or the branch-circuit load terminations.

 

[Rocky_H]

Does any of the advice on appropriate tesla charger wire sizing change as a result of the 2020 updates to the code here?

Huh, interesting question to bring up, but I don't see anything there that would change this.

"Section 110.14(C)(2) covers separately installed pressure connectors such as power distribution blocks and recognizes the fact that many of them differ from circuit breaker terminals in that they are often rated higher than 75°C.

According to the new exception, a run of 90°C rated branch circuit conductors installed between 90°C rated power distribution blocks can be used at the maximum ampacity based on 90°C."

So it introduced some kind of specific exception case for things like "power distribution blocks", which could have lugs rated up to 90 degrees C. Residential consumer electrical equipment does not have that. Home breakers are only rated to 75 C and the connection lugs in EVSEs like the Tesla wall connector or others or regular outlets also are only rated to 75 C. So I still don't see any cases where you would get to use the 90 degree C rating of wire for these kinds of EV charging circuits.

The other thing about one of two ratings, I think still wouldn't change.

"210.19(A)(1) allows the larger of the following two values to be used for the final selection of the conductor:

Either 125% of the continuous load without any additional adjustment or correction factors,
OR
100% of the load (not 125% of it) after applying adjustment and correction factors."

It says the larger of the two. So let's say 48A charging. If you start at 48A and apply "adjustment and correction factors", which I'm not sure what all would go into that, you could see where that comes out. If that came to something bigger than 60, then I guess you're supposed to use that, but that sounds unlikely or a pretty rare case for some pretty harsh conditions. I think the +25% is already a pretty big oversize.

I feel like I'm in the kind of educated guess area on this, though, so not quite as confident. I am kind of getting the impression from this that the standard +25% that was being used before is the more cautious extra margin case, and this exception provision of correction factors sounds like a more big job industrial type of use case.

 

[mongo]

Huh, interesting question to bring up, but I don't see anything there that would change this.

"Section 110.14(C)(2) covers separately installed pressure connectors such as power distribution blocks and recognizes the fact that many of them differ from circuit breaker terminals in that they are often rated higher than 75°C.

According to the new exception, a run of 90°C rated branch circuit conductors installed between 90°C rated power distribution blocks can be used at the maximum ampacity based on 90°C."

So it introduced some kind of specific exception case for things like "power distribution blocks", which could have lugs rated up to 90 degrees C. Residential consumer electrical equipment does not have that. Home breakers are only rated to 75 C and the connection lugs in EVSEs like the Tesla wall connector or others or regular outlets also are only rated to 75 C. So I still don't see any cases where you would get to use the 90 degree C rating of wire for these kinds of EV charging circuits.

The other thing about one of two ratings, I think still wouldn't change.

"210.19(A)(1) allows the larger of the following two values to be used for the final selection of the conductor:

Either 125% of the continuous load without any additional adjustment or correction factors,
OR
100% of the load (not 125% of it) after applying adjustment and correction factors."

It says the larger of the two. So let's say 48A charging. If you start at 48A and apply "adjustment and correction factors", which I'm not sure what all would go into that, you could see where that comes out. If that came to something bigger than 60, then I guess you're supposed to use that, but that sounds unlikely or a pretty rare case for some pretty harsh conditions. I think the +25% is already a pretty big oversize.

I feel like I'm in the kind of educated guess area on this, though, so not quite as confident. I am kind of getting the impression from this that the standard +25% that was being used before is the more cautious extra margin case, and this exception provision of correction factors sounds like a more big job industrial type of use case.

I think the idea is this: Breaker at 75 to 75 wire to block to 90 wire to block to 75 wire to 75 device. Let's you downsize the long part of the run (if you don't care about voltage drop).

 

[Rocky_H]

I think the idea is this: Breaker at 75 to 75 wire to block to 90 wire to block to 75 wire to 75 device. Let's you downsize the long part of the run (if you don't care about voltage drop).

Yeah, I could see that, and it fits with my idea of it going with big job kinds of situations, like where a basement of a bigger multi-story building has the electrical system, and they have to send the connections up into each floor or something. Those are power distributions, long runs, etc.