davewill
Active Member
No. Romex always has to use the 60C column. It's a code requirement that overrides the rating of the cable itself.
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Tesla wall charger users. What size wire is your charger using?
- Thread starter ozziegn
- Start date
Yes, I think that's right and I believe if you exceed that you are supposed to go up one wire size (down one number). This is something you want to do as the car measures the resistance of this wire before allowing charging.
kkillebrew
Banned
6-3 has an un insulated ground wire for a single phase circuit. You can use it with the wall charger but be aware both sides of the insulated wires (white and black) are hot in relation to ground, unlike many 120V runs.
Right you are. It actively measures load resistance, this way it will not be deceived (for long) by a very short run of insufficiently sized cable yielding the same cold resistance as a longer properly sized longer run.
Which is why, if you use a 6-3 cable with white and black wires, you must mark the white one with red tape at both ends.
Excuse the nerdy EE stuff but it is actually measuring the source resistance i.e. the total resistance between the source and the charger. It cannot know what the cause of that resistance is and therefore it does not know where it is either so it assumes that it is between the panel and the charger and does the safe thing: reduce charging current or shut down altogether. Most of the time the source is going to be improperly torqued terminals, incompletely seated plugs, corrosion etc. and reducing current is clearly the wise thing to do but should you use too long a wire, even though it be of the proper current rating, it will shut down then too. Notice that I did not say proper size because the code requires increasing size as length of the run increases.
Allistah
Member
I used 6ga wire on a 50A breaker which maxes out at 40A to the car (80% of breaker rating is what you can do for long periods). The breaker gets warm, connections get warm, but that's about it. I'd swap that breaker out for a 50A, and dial it down to the proper setting, you should always round down. I wish I would have gone up one wire size though, I would still use a 50A breaker and 40A to the car, just makes me a little paranoid when things get warm.
Black306
Active Member
I went with the 6ga/50A breaker combo cause the Wall Connector has a NEMA 14-50 in between. Decided this route for the flexibility to run a welder or use a mobile connector, with a 14-50 adapter, if something happens to the Wall Connector. Plus, it was easier to setup; less sheetrock work.
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Allistah
Member
Thats what I did. I. I have a plug like that for our 5th wheel trailer. At first I bought a cheap $10 plug from Home Depot. That was a huge mistake. Not sure which outlet you put on there, but when I got the good one, I took some up close pics of it, and whoa, what a huge difference. Then it made sense why the cheap one was getting so hot - even though it was brand new. The pic below shows the quality one, and the cheap one. Both are new. The cheap one even had much less contact area with the prongs that go into it so it was a double whammy. If you're interested, the good one is a Hubbell 9450A. I dropped the pic of it below. Oh also, the terminals where the wires go in on the Hubbell (bottom pic) are of a much better design that doesn't crush the wires and spread them out like the cheap one. You can see that when it clamps them, its at an angle to keep the strands together which is nice. I just can't say enough about getting a quality outlet for something that moves such high current.
I would also recommend that you look up the torque ratings for the lugs on the breaker, as well as the back of this outlet. I usually never do that for fear of breaking something but I went exactly by the book this time and I found out that the terminals on the breaker weren't tight enough and the same on the outlet. That allowed me to get them tighter - and to spec without breaking them. All this helped with heat - the right torque on both ends of the wires, plus this quality outlet really helped. Thinking back, I couldn't believe how bad of quality that cheap outlet was.
StealthP3D
Well-Known Member
You have some good answers on conduit size but I just wanted to elaborate on what I learned on my most recent install.
1" is a good conduit size for your requirements but be aware that 1" schedule 80 (required for areas subject to impact damage) has the same outside diameter as schedule 40 but the I.D. is significantly smaller. Also, unless you use adapter fittings to transition from 1" conduit to a different size conduit body, the size of the conduit you select will determine the size of the conduit bodies you use.
I used schedule 80 conduit (allowed a shallower burial depth than sch. 40) and found that the 1" conduit bodies were a little tight to wrestle the AWG #6 wires through. This may have been compounded by the smaller I.D. of the schedule 80 conduit. The 1 1/4" conduit bodies are longer (and wider) which makes it a lot easier to fit the wires.
I did find that with a little cable lube it was easy to pull three AWG 6 and one AWG 8 wires through two 90 degree elbows and about 30 feet of schedule 80 1" conduit.
Conduit body:
Black306
Active Member
I currently have a $10 outlet from Home Depot, but I have a Bryant on order. A part of me is wondering if part of the problem with a Leviton is that people aren’t torquing them down properly. Even the original breakers in my panel weren’t torqued down by the builders.
Had to torque them myself. (I have 5 torque wrenches for various things. )I’m thinking about stepping up the current draw via the car and taking some measurements with an infrared temp gun on the outlet. Then switching to the Bryant and doing the same test.
Allistah
Member
I’m thinking about stepping up the current draw via the car and taking some measurements with an infrared temp gun on the outlet. Then switching to the Bryant and doing the same test.
I heard that the cheap one doesn't have spring loaded contacts on the inside so they weaken over time. The where the wires go in, they’re not strand friendly so the strands spread out and they get crushed which decreases the contact area quite a bit and of course, generates more heat. I had a hard time spending the money on the Hubbell one but when I got it and took a close look I could really see the value in it. Then when the heat generation went down, it was obvious it was the right thing to do.
I was also shocked that what I thought was tight enough, wasn’t right enough when I put a torque wrench on it. Can’t stress to be ultra careful when sticking a torque wrench into you panel. I turned the breaker off and then checked no voltage multiple ways and then checked again between live breakers and the one I turned off to make sure it was off. Then I had leather work gloves on as well. Sort of freaked me out but man, can’t be too careful doing something like this. Good luck to you!
Black306
Active Member
I learned long ago what AC current from a wall outlet feels like and yes it was the hard way.
To those considering adding a Wall Connector or an outlet, make sure your main breaker is off!! Verify with a volt meter on the buses between each bus and each bus to neutral. You don’t want to know what AC feels like.
Have you checked that your connections are tight? If they are loose you will get a bad connection and some heat build up. Running 6/2 Romex from panel to junction box other side of house. Transitions to THN wire in conduit to go out the wall and up to the charger. On 60 amp breaker running at 48 amp. Breaker is cool.
Black306
Active Member
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