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60 amp or 50 amp breaker for Tesla wall charger?

*sigh* 6 gauge Romex isn't rated high enough for a 60A circuit, so that would have to be set as a 50A circuit unless you do that change to THHN in conduit.
Yeah wasn't even thinking about it during his install. But I specifically told him that the charger needs a 60 amp breaker since the car will be charging at 48 amps according to the manual. I guess I'll keep it at 40 for now until I get around to replacing the small run with THHN. I could probably even just set the car to 44amps since 44x1.25 is the rated 55amps. Not that it makes a difference though. A little over 2 hours to recharge daily isn't bad at all.
 

Rocky_H

Well-Known Member
Feb 19, 2015
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Boise, ID
Hmm looking at Romex vs THHN I see that newer Romex is rated at 90c now
Where do you think you are seeing that?
so THHN and Romex both appear to have the same rating according to what's sold at Homedepot.
No, they're not.
I thought Romex was 60C.
It is.

I think I know what you are looking at that's giving this idea. If you read the specifications for Romex cable, it does list that the individual wires inside the bundled cable are jacketed with insulation that is 90 degree rated. But when you look at allowed ampacity tables, it shows that using the NM-B cable as a whole has to use the 60 degree C rating. Here's an example of that table:


And for @LoudMusic 's question, that's a good table to use to see the actual ratings. The table you were linking to is for calculating voltage drop. And it's showing it just listed by current flow, but not what the wire rating level is.

If you Google for "ampacity table", that's always the first link that comes up.
 
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Where do you think you are seeing that?
It was just in the description. I'll limit myself to 44amps until I get around to upgrading it.
It's funny to that you look at the frequently bought together with a 60amp breaker. I wonder how many Tesla chargers are out there with these types of setups?


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LoudMusic

Active Member
Jul 21, 2020
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Arkansas
It was just in the description. I'll limit myself to 44amps until I get around to upgrading it.
It's funny to that you look at the frequently bought together with a 60amp breaker. I wonder how many Tesla chargers are out there with these types of setups?


It's also very commonly used with RVs, though they should be buying 50 amp breakers.

We have a couple 60 amp breakers in our new house - I think they are air conditioner units or the stove possibly? I need to review the electrician's notes.
 
Thinking about it I should probably bump up the wire to #6 THHN he used romex 6/2. I don't think certified electricians research EV charging enough.
Though 40amps would be plenty as well I drive 100miles per day and 48A puts it back in a little over 2 hours so a little longer makes no difference.

I can easily take care of the wire change myself. I just needed someone to trench the 100ft to my garage and add a panel I wanted that done by a professional.
The electrician used 6/2 romex inside a conduit? If so, that should not be done.
 
There are many problems but that's not one of them. No conduit though just 6/2 Romex on the wall.
OK, thought it may be a heat issue inside the conduit. BTW: I shouldn't have said, "that should not be done", but I do not recommend it as romex does not dissipate heat as well as single strand 6 gauge wire. As a general rule, you must use larger conduit, to accommodate romex, so when factoring in the larger conduit needed, it is usually not cost effective to use. I am a contractor in California, here romex is generally used in wood framed homes, inside walls, with no conduit. It is not allowed outside, unless it is the UF variety of romex and is in conduit. Some areas consider a garage, "outdoors", others do not.
 
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