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Anyone use this Romex 6/3 cable during install?

GSP

Member
Supporting Member
Dec 28, 2007
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Regarding the 6 vs 4 gauge wire along with the 48 amp vs something lower issue on the INPUT side of a WC, however looking at and handling the cord from the WC to the plug on the OUTPUT side of a WC, it seems so thin and pliable even when cold. Does anyone know the size of the wires inside the cord's rubber sheath?
Tesla has used two conductors in parallel for each of the hot wires [4 conductors total + ground] in their UMC and WC cables. I don’t remember the AWG used. This allows the cable to be smaller and much more flexible than using single conductors like conventional extension cords do.

Tony Williams at QuickChargePower sells this special cable. I bought a 50’ extension for my UMC from QCP with a standard J1772 plug for compatibility with other EVs. It has been nice to have on several occasions.
 
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Tesla has used two conductors in parallel for each of the hot wires [4 conductors total + ground] in their UMC and WC cables. I don’t remember the AWG used. This allows the cable to be smaller and much more flexible than using single conductors like conventional extension cords do.

Tony Williams at QuickChargePower sells this special cable. I bought a 50’ extension for my UMC from QCP with a standard J1772 plug for compatibility with other EVs. It has been nice to have on several occasions.

That is the first time I have heard of that, thanks for the education, now a follow up. Do you know how these connectors are attached to the unit? The same as the INPUT connectors or something different?
 
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Did you do a Conduit Percentage Fill Calculation? 😈
Screen Shot 2021-10-15 at 9.30.24 AM.png

that was the bend that was tricky.
 

Rocky_H

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Feb 19, 2015
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Boise, ID
Wouldn't it be more typical to use stranded here instead of romex? I'd expect that pull to be really hard, even with larger conduit.
If someone can do conduit the whole distance, then sure, you probably would, but I'm not sure where the rest of this installation went. If this was the section that had to be outside of a wall, but then the rest of it was going to go up through an insulated wall, then you would want to use Romex for that other part. So it was probably easier to use one type of cable for it, with some in wall and some in conduit, than to splice it in a junction box for those two different areas.
 

jsight

Active Member
Apr 5, 2018
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Charleston
If someone can do conduit the whole distance, then sure, you probably would, but I'm not sure where the rest of this installation went. If this was the section that had to be outside of a wall, but then the rest of it was going to go up through an insulated wall, then you would want to use Romex for that other part. So it was probably easier to use one type of cable for it, with some in wall and some in conduit, than to splice it in a junction box for those two different areas.
Oh, that makes perfect sense. Thanks for the explanation.
 

gavine

Petrol Head turned EV Enthusiast
Apr 1, 2014
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Philadelphia, PA
If someone can do conduit the whole distance, then sure, you probably would, but I'm not sure where the rest of this installation went. If this was the section that had to be outside of a wall, but then the rest of it was going to go up through an insulated wall, then you would want to use Romex for that other part. So it was probably easier to use one type of cable for it, with some in wall and some in conduit, than to splice it in a junction box for those two different areas.
Couldn't you strip the jacket off of just the Romex section that is going-into the conduit?
 

mswlogo

Well-Known Member
Aug 27, 2018
8,424
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MA, NH
This is an easy fix. Adjust your HPWC to 50 amp and swap out your breaker to 50 amp.

This will increase your Home/EV safety and get a huge Thumbs-Up from all your friends here at TMC. 👍
You don’t technically need to swap the breaker. But it would be a little safer.

You are allowed to round up on the breaker since they don’t make a 55A to protect the wire in the event of a short. It’s still a 55A circuit.

But you need to round down on the load since you can’t set the load to 55A. So yeah set HPWC to 50A.
 
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.
12AWG is acceptable for a 20A circuit, but will generate more waste heat that will translate into a larger voltage drop on the wire; if the voltage drop is large enough (typically > 10V), the car will reduce its draw from 16A to 12A, eliminating the benefit of installing a 5-20 in the first place. If, your breaker box is in/near your garage and the wire run is, say, 50' or less, 12 *should* be fine, but personally I'd err on the side of caution and use 10AWG if you can.

If you go to this calculator, you can see the voltage drop between the two gauges at your circuit length (remember this is a round trip circuit, so enter double the length of your wire run). At a 100' circuit length (50' wire run), you'll see that you'll lose 5.2V at 16A with 12AWG wire, but only 3.3V with 10AWG. At 120V, that's a 30.4W difference in wasted power - not a huge amount, but probably adds up over time.

I have a particularly long run - about 150' - but I'm 10AWG all the way, including a 10/3 extension cord; I'm measuring ~112V at the car, and charging at around 6-7mph at current PNW outdoor temperatures, more than enough for my daily needs. I do expect the efficiency to go down in the winter due to battery conditioning, but per other accounts, it shouldn't go down by much.
 

Rocky_H

Well-Known Member
Feb 19, 2015
8,789
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Boise, ID
Wouldn't it be more typical to use stranded here instead of romex?
This 6ft section was not solid wire.
I think the word "stranded" was just a mistaken use of a word. That's not what was meant. All of these thick wires are stranded inside, whether they are in the installation format of wire in conduit or Romex. They have to be to get any flexibility to work with them at all. Solid wires are only used in the thin ones, like up to about 12 gauge? I'm not sure if you can get solid 10 gauge or not, but once you are talking about 8 or 6 or larger, it's all stranded inside.
 
I think the word "stranded" was just a mistaken use of a word. That's not what was meant. All of these thick wires are stranded inside, whether they are in the installation format of wire in conduit or Romex. They have to be to get any flexibility to work with them at all. Solid wires are only used in the thin ones, like up to about 12 gauge? I'm not sure if you can get solid 10 gauge or not, but once you are talking about 8 or 6 or larger, it's all stranded inside.
Phew, I was thinking about dealing with solid at that size and would need have hit the hand exercise grips for a few weeks prior :)
 
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.
Johnny Vector . if you think 6/3 romex is not for 60 amp breaker then which size cable do you recommend ?
 

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