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Anyone use this Romex 6/3 cable during install?

Jun 26, 2020
68
74
Maine
That’s exactly what I used. I didn’t need 50’ though so I bought it by the foot from Home Depot web site, along with the 60A breaker which my local store didn’t have in stock.

note: I haven’t actually connected it up to the wall charger yet though... sidetracked by other projects while waiting for delivery!
 

Johnny Vector

Member
Jun 21, 2020
75
111
Maryland
I am thinking about getting this 6/3 wire from Romex at HomeDepot. This would be the wire from a 60amp breaker to the Gen 3 wall charger.

Has anyone installed with this wire for their Tesla and was it a good experience?

That is only rated for 55 amps. DO NOT put it on a 60 amp breaker. Use a 50 A breaker for this. Your house probably won't burn to the ground if you use a 60 A breaker with wire not rated for 60 A, but is that really a chance you want to take?

If you want to use 6 gauge wire for 60 A, you need to pull THHN or THWN through a conduit.

See Table 310.16 in the National Electrical Code, which you can access for free here.
 
Last edited:

jmaddr

Member
Mar 29, 2019
860
853
Florida
I wouldn't use Romex on a 60A circuit. I recommend and myself purchased 3 individual 25' 6 guage runs in black, red, and green from HD and ran them in conduit.
 
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Privilege

Member
Jul 5, 2020
15
9
Los Angeles
I bought the wire cut to length. I had a short 2 foot run. So I bought 4 feet of 6 gauge THHN black wire and cut it into 2 pieces. Then I bought a 2 foot cut of green 6 gauge for ground, I know others are using 8 gauge. I didn't want to end up with extra so no need to buy a roll.
 
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Johnny Vector

Member
Jun 21, 2020
75
111
Maryland
If you don’t want to run conduit and separate wires and want similar convenience of NM cable (Romex), you can pull MC cable. 6/2 is all you need for the Wall Connector and you’ll get 48A on your 60A breaker.

MC Cable | Wire & Cable Your Way

Oh, good point. My hate for cutting Metal Clad cable burns with such a fiery rage that I sometimes forget it exists. But once you get past having to cut it without damaging the insulation, it is easier to install than conduit. For a short straight run, I'd use conduit. If you have to run like 75 feet around various corners and bends, MC is probably the easier way to go.
 
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Dugdale

Member
Jun 25, 2020
6
6
Colorado
Thanks for all the input.

I'm a little confused, it's true that the wire I linked to only has a max 55 amp rating, but the Tesla wall charger data shows the
Maximum output (amps) of 48 amps on a 60 amp breaker. If the max output is only 48amps for the charger, can't I use the 55amp cable?

Now that I think about it, it's probably a bad idea because a future owner of this house might add a different charger and calculate it off the breaker and not the cable which might not end well.

Since the garage has unfinished walls I would rather not run conduit but use a jacketed cable for easier install.
 
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Rocky_H

Well-Known Member
Feb 19, 2015
5,848
6,684
Boise, ID
I'm a little confused, it's true that the wire I linked to only has a max 55 amp rating, but the Tesla wall charger data shows the
Maximum output (amps) of 48 amps on a 60 amp breaker. If the max output is only 48amps for the charger, can't I use the 55amp cable?
No, that's not how the current ratings work. The amp ratings in the ampacity tables are for the circuit rating. So if you want a 60A circuit, you need to use a gauge that says it can support at least 60A. That wire only goes to 55A, so you can't use it for a 60A rated circuit.

Circuit ratings are normally for intermittent temporary use up to their full ratings. So things like ovens and clothes dryers have heating elements that cycle on and off for several minutes at a time. The wires get time to cool down, so they can run at full 100% capacity for short bursts. But electric code requires that for permanent loads (several hours), they can only run at 80% of the circuit's rated capacity. So that's where the 48A for many continuous hours on a 60A circuit comes in.

But you don't get to evaluate whether you think your charging is going to be short term or long term. Code was modified a few years ago to just define all EV charging as permanent loads.
 

Privilege

Member
Jul 5, 2020
15
9
Los Angeles
You can try running 4 gauge romex, it's good for 70 amps. You have to make sure the breakers you use will take 4 gauge, I think they have some at HD. I initially tried to run 4 gauge and realized it didn't fit in the breaker I bought but I remember they had a breaker there that it would fit. I know the wall charger can accept the 4 gauge but it wasn't easy as using 6 gauge, it's harder to bend and work with.
 

Johnny Vector

Member
Jun 21, 2020
75
111
Maryland
No, that's not how the current ratings work. The amp ratings in the ampacity tables are for the circuit rating. So if you want a 60A circuit, you need to use a gauge that says it can support at least 60A. That wire only goes to 55A, so you can't use it for a 60A rated circuit.

Circuit ratings are normally for intermittent temporary use up to their full ratings. So things like ovens and clothes dryers have heating elements that cycle on and off for several minutes at a time. The wires get time to cool down, so they can run at full 100% capacity for short bursts. But electric code requires that for permanent loads (several hours), they can only run at 80% of the circuit's rated capacity. So that's where the 48A for many continuous hours on a 60A circuit comes in.

But you don't get to evaluate whether you think your charging is going to be short term or long term. Code was modified a few years ago to just define all EV charging as permanent loads.

Exactly this. The easy-to-remember way of thinking about it is that the breaker is to protect the wire, not the stuff connected at the end of the wire.
 
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Pilot1226

Member
Dec 20, 2019
355
155
USA
I don't mean to hijack the conversation, but if I was going to run a new circuit for a 120V 20A wire (5-20), what wiring should I use? Romex 10/3? 10/2? Should I use 12 gauge which supports 20A, or should I push for 10 gauge which supports 30A, for better cooling/resistance properties? It will have a 20A breaker, regardless, and an industrial 5-20 outlet on the other end in a weatherproof outdoor enclosure.
 

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