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Thoughts on this install for a 14-50 install with subpanel.

Rocky_H

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Feb 19, 2015
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Boise, ID
For a 50A circuit you can't use 8 gauge NM-B (Romex wire), would need to use 6 gauge. The NEMA 14-50 receptacle requires 3 conductors, not 4 conductors plus the ground wire, so 6/3 NM-B. (Note: The ground wire is present, not counted as a conductor.)

If NJ and your local jurisdiction has adopted the 2017 version of the National Electrical Code (NEC) then you will need to install a GFCI circuit breaker (now required by code for all EV charging receptacles.) Since there is no GFCI receptacle available for the 14-50 receptacle a GFCI circuit breaker ($100) would be required.
Dang, you're a star on this stuff. As I was reading the initial post, I was already keeping notes in my head of the corrections this needed, and you knocked them all out, except for maybe one other I would mention:
1. Make sure the electrician doesn't use a Leviton outlet. They are horribly cheap and crappy and way too easy to have bad, loose connections. Any of these other brands are all pretty good: Cooper, Bryant, Hubbel.
2. It says 50A breaker, but 8 gauge Romex is only good for up to a 40A circuit, so that's not OK.
3. Yes, the naming 8/3 is already defined as 3 conductors, plus the ground wire.
4. And even if it was switched to 6/3, that can't be swapped up to a 60A circuit later, as @golferguy was suggesting.
5. An outlet installation for EV does require using an annoyingly expensive GFCI breaker.

Why do you need a subpanel ? If you don't have space in the panel you can buy a Double Breaker that uses the space of 1 breaker to give you 2. not sure what panel you have.
I am puzzle about the need to add a subpanel just to install a new circuit breaker?
- this is certainly a clean solution but would using some tandem circuit breakers
could provide some room for the new EV line inside the main panel?
I don't know why so many people assume that ALL panels can ALWAYS use tandem breakers. I have a fairly decently modern Square D Homeline panel from 1996, but it does not allow any tandem or quad breakers. So a subpanel may be necessary and isn't that bad of a deal.

Instead of 8/3 Romex cable I like better using a conduit with wires inside
to get a cleaner looking install, unless there are too many curves a cable migt be simpler.
If it's using Romex, it's probably because it's in a location that needs to use Romex. The place the line is running usually determines if you use wire in conduit, or cable. Above ceilings or inside walls is generally not going to be conduit.
 
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Sophias_dad

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Jul 29, 2018
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for clarification, sometimes 8gauge is ok for Nema 14-50 for 50A. Here is a good chart of different cable types.

8 gauge romex is never okay for 50 amps. Romex(NM-B) is always required to use the 60C rating.

Yes, 8 gauge NM-B could technically used for a 14-50 outlet, but only because there is no 14-40 outlet and a special exception is made for that. You'd be expected to put a 40 amp breaker on that 8 gauge NM-B.

So, yeah, individual #8 in conduit is okay for 50 amps.
 

golferguy

Member
Jan 30, 2021
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SE Florida
No, 8 gauge romex is never okay for 50 amps. Romex(NM-B) is always required to use the 60C rating.

Yes, 8 gauge NM-B could technically used for a 14-50 outlet, but only because there is no 14-40 outlet and a special exception is made for that. You'd be expected to put a 40 amp breaker on that 8 gauge NM-B.

So you disagree with the publication at 75C and 90C? I did not type ROMEX.
 

Sophias_dad

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So you disagree with the publication at 75C and 90C? I did not type ROMEX.
The rest of this entire thread, and OP's original question, was specified with ROMEX as the type of cable.

Just trying to keep people from burning down their house when they either don't follow the link, or don't understand what they read there. There seem to be plenty of people happy to read a few lines of a post and start installing.
 
For a 50A circuit you can't use 8 gauge NM-B (Romex wire), would need to use 6 gauge. The NEMA 14-50 receptacle requires 3 conductors, not 4 conductors plus the ground wire, so 6/3 NM-B. (Note: The ground wire is present, not counted as a conductor.)

If NJ and your local jurisdiction has adopted the 2017 version of the National Electrical Code (NEC) then you will need to install a GFCI circuit breaker (now required by code for all EV charging receptacles.) Since there is no GFCI receptacle available for the 14-50 receptacle a GFCI circuit breaker ($100) would be required.
Check with your inspector. If you do an outlet a GFCI breaker will likely be required. If you hardwire a wall connector it may not since most of them have GFI protection built in.
 

jcanoe

Active Member
Oct 2, 2020
4,372
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Maryland
Check with your inspector. If you do an outlet a GFCI breaker will likely be required. If you hardwire a wall connector it may not since most of them have GFI protection built in.
A ground fault circuit interrupt (GFCI) device is designed to trip when the GFCI detects even a very small difference between the line current supplied to the load and the neutral current returning from the load. Please explain how a GFCI would work without the neutral wire connection, i.e. for a hard wired Level 2 (240V) EVSE installation.
 
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A ground fault circuit interrupt (GFCI) device is designed to trip when the GFCI detects even a very small difference between the line current supplied to the load and the neutral current returning from the load. Please explain how a GFCI would work without the neutral wire connection, i.e. for a hard wired Level 2 (240V) EVSE installation.
from page 4 of the Gen 3 wall connector manual: “Ground Fault Circuit Interrupter - Integrated, no additional required”

Think about your question a bit - if the wall connector couldn’t figure out a ground fault with its connections, how would a GFI breaker? It doesn’t magically have any connections that connector doesn’t.

GFCIs detect differences between the supplied current and the returning current. For a standard 120V outlet, that’s the difference between the current in the hot wire and the neutral wire. In a 240V circuit, there are 2 hot wires 180º out of phase. The GFCI simply detects the current difference between the two hot wires. (Remember, we’re dealing with AC voltage here, so both wires function as supply and return, depending on where you are in the cycle.)
 

Watts_Up

Active Member
Mar 4, 2019
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In a galaxy far, far away
from page 4 of the Gen 3 wall connector manual: “Ground Fault Circuit Interrupter - Integrated, no additional required”

Think about your question a bit - if the wall connector couldn’t figure out a ground fault with its connections, how would a GFI breaker? It doesn’t magically have any connections that connector doesn’t.

GFCIs detect differences between the supplied current and the returning current. For a standard 120V outlet, that’s the difference between the current in the hot wire and the neutral wire. In a 240V circuit, there are 2 hot wires 180º out of phase. The GFCI simply detects the current difference between the two hot wires. (Remember, we’re dealing with AC voltage here, so both wires function as supply and return, depending on where you are in the cycle.)
I imagine that the GFCI breaker needs to be able to check both
- the current difference between two phases and also
- the difference between each phase and the Neutral ,
in the case a device using both type of connections, such as a Range Oven.
 
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jcanoe

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Oct 2, 2020
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Maryland
I imagine that the GFCI breaker needs to be able to check both
- the current difference between two phases and also
- the difference between each phase and the Neutral ,
in the case a device using both type of connections, such as a Range Oven.
A GFCI is not required for a 14-50 receptacle for a Range/Oven. The purpose of having GFCI protection on the receptacle is to protect the user when inserting the plug or removing the plug. The plug on a Range/Oven is rarely unplugged from the receptacle.
 
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Sophias_dad

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Jul 29, 2018
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A GFCI is not required for a 14-50 receptacle for a Range/Oven. The purpose of having GFCI protection on the receptacle is to protect the user when inserting the plug or removing the plug. The plug on a Range/Oven is rarely unplugged from the receptacle.
GFCIs don't only protect when plugging/unplugging. They protect at all times but aren't required for large, fixed-in-place items because those are unlikely to have external wiring damage and because of their heavy metal construction they are unlikely to have internal wiring damage that allows the hot to connect to ground.

One example would be a hair dryer plugged in next to a sink all the time. If it happens to fall into a sink full of water or has an cord failure that allows the user to contact the hot line and a faucet knob at the same time, the GFCI should trip. Additionally, if it were for only when plugging/unplugging, we'd have them required everywhere rather than only where water is likely to be(outdoors, garages, kitchens, pools, bathrooms, and so on)
 

jcanoe

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Oct 2, 2020
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Maryland
GFCIs don't only protect when plugging/unplugging. They protect at all times but aren't required for large, fixed-in-place items because those are unlikely to have external wiring damage and because of their heavy metal construction they are unlikely to have internal wiring damage that allows the hot to connect to ground.

One example would be a hair dryer plugged in next to a sink all the time. If it happens to fall into a sink full of water or has an cord failure that allows the user to contact the hot line and a faucet knob at the same time, the GFCI should trip. Additionally, if it were for only when plugging/unplugging, we'd have them required everywhere rather than only where water is likely to be(outdoors, garages, kitchens, pools, bathrooms, and so on)
Bonus round question; why does the NEC not require GFCI protection for a 14-50 receptacle used for an RV motor home hook up. (In this application the 14-50 receptacle is most likely outdoors where the RV operator may be standing on wet grass, in a puddle, etc.) What is it about an RV motor home's electrical system that is incompatible with a GFCI?
 

Sophias_dad

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Jul 29, 2018
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Bonus round question; why does the NEC not require GFCI protection for a 14-50 receptacle used for an RV motor home hook up. (In this application the 14-50 receptacle is most likely outdoors where the RV operator may be standing on wet grass, in a puddle, etc.) What is it about an RV motor home's electrical system that is incompatible with a GFCI?
I didn't know GFCIs weren't required there, but my best guess is that there are likely big electric motor loads (A/C, refrigerator) and those seem prone to accidental tripping of GFCI's.

A quick search got me this, which doesn't say exactly the same reason, but does say they would be tripping all the time. Thirty- and fifty-amp GFCIs in campgrounds – not a good idea
 
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Spikeitaudi

Member
Aug 11, 2021
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Nj
Just incase for those that helped here and were curious I had my other electrician come out and he had many more suggestion. I can not install a sub panel in my current location where my main panel is at as it is behind a double door in my finished basement. The double doors give access to the panel and all the cable runs for the house. No extra room. As my panel is full he is trying to see if we can use tandem or move things around if possible and run a sub panel to my garage and run the NEMA connection from that sub panel. It’s never easy.
 

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Sophias_dad

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Just incase for those that helped here and were curious I had my other electrician come out and he had many more suggestion. I can not install a sub panel in my current location where my main panel is at as it is behind a double door in my finished basement. The double doors give access to the panel and all the cable runs for the house. No extra room. As my panel is full he is trying to see if we can use tandem or move things around if possible and run a sub panel to my garage and run the NEMA connection fro. That sub panel. It’s never easy.
I'm a little surprised he doesn't know if you can go tandem, unless its a very unusual main panel. It makes me a little suspicious.

If you could post a picture of any model information on your main panel, someone here could probably answer that question, so at least you'll have some ammo when the electrician comes back and says 'nope' you need an entirely new main panel, or so on.
 

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