It's a concern, but I've felt the conductors of my plug after drawing 16A for hours and they are near room temperature.
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Convert NEMA 5-20 to 6-20?
- Thread starter ratsbew
- Start date
eprosenx
Active Member
Nice pictures.
I am guessing that the screw was not torqued down enough or that insulation was caught under the screw. This causes heating obviously.
This is a great example of why quality work is so critical and why I don’t recommend charging EV’s on daisy chained 120v circuits. Too many possible locations for failure!
It is also a good example of why we require electrical connections to be inside fire resistant boxes
I am so glad it was not more serious!
Dmagyar
Member
No this was in my own home, and was installed by myself. Nothing was loose, and no insulation under the clamping screw. The problem was the proximity of grounding yolk, that’s pointed out in by the picture with the pen and the new design of that’s same manufacturer’s heavy duty receptacle. The insulation melted back because of the heat produced by the Heat of the fault, which I’m attributing to the the clamping force of the hot on the plug prong, which had to be cut off as it had welded itself together inside the receptacle and that created the heat. I posted it because of the amount of time between install and it’s ultimate failure. Anyone charging their car via a 120/or 240 volt receptacle need to use industrial rated receptacles, to help avoid this situation. PS every thing was pigtailed, not daisy chained...Nice pictures.
I am guessing that the screw was not torqued down enough or that insulation was caught under the screw. This causes heating obviously.
This is a great example of why quality work is so critical and why I don’t recommend charging EV’s on daisy chained 120v circuits. Too many possible locations for failure!
It is also a good example of why we require electrical connections to be inside fire resistant boxes
I am so glad it was not more serious!
Last edited:
eprosenx
Active Member
Interesting.
I don’t know what caused this heat for sure. I would first suspect it was due to a loose connection from the wire to the screw, but as you point out it could also be an issue between the plug blade and the clamp in the receptacle.
With these photos I can’t tell which (and even if inspected in person I don’t know that I have the knowledge to tell).
I would think it possible that the plug being welded in the socket could be caused by heat from a loose wire, but super hard to say. (Maybe not truely welded but just stuck?)
I am glad nothing more serious happened! Indeed, I am anti 120v charging in general.
I agree that if you are going to do it, get a high quality receptacle (but also you have to worry about every receptacle or wire nut in the chain…)
Interesting.
I don’t know what caused this heat for sure. I would first suspect it was due to a loose connection from the wire to the screw, but as you point out it could also be an issue between the plug blade and the clamp in the receptacle.
With these photos I can’t tell which (and even if inspected in person I don’t know that I have the knowledge to tell).
I would think it possible that the plug being welded in the socket could be caused by heat from a loose wire, but super hard to say. (Maybe not truely welded but just stuck?)
I am glad nothing more serious happened! Indeed, I am anti 120v charging in general.
I agree that if you are going to do it, get a high quality receptacle (but also you have to worry about every receptacle or wire nut in the chain…)
FWIW, @Dmagyar has posted elsewhere on these boards that they are (or were) a licensed IBEW electrician. Under normal circumstances I would say it would be a great place to start by looking at torque etc, but for an electrician, in their own home, I would imagine a regular outlet is installed / torqued properly.
DangerRuss
Member
Super useful thread. Thank you all.
I looked through and didn't see mention of a related question.
Apologies if I missed it.
Related question:
Will the same approach work on a dedicated circuit 120v TT-30?
There are a number of 240v 30amp receptacles obviously.
6-30?
14-30?
10-30?
Thank you,
-Russell
I looked through and didn't see mention of a related question.
Apologies if I missed it.
Related question:
Will the same approach work on a dedicated circuit 120v TT-30?
There are a number of 240v 30amp receptacles obviously.
6-30?
14-30?
10-30?
Thank you,
-Russell
6-30.
Note that Tesla doesn't offer a 6-30 adapter for the UMC. However evseadapters does. They also offer a TT-30 adapter.
DangerRuss
Member
Thank you much.
My google-fu suggests that I need:
1 strand of 10 gauge wire
1 6-30 receptacle
1 6-30 adapter for my charger, likely to come from a 3rd party
Thanks!
-Russell
My google-fu suggests that I need:
1 strand of 10 gauge wire
1 6-30 receptacle
1 6-30 adapter for my charger, likely to come from a 3rd party
Thanks!
-Russell
DangerRuss
Member
Humm…. I would think you would need a 30a / 240v (double pole) breaker, a 6-30 receptacle, plus a 3rd party adapter.
what’s the wire for?
DangerRuss
Member
It's only 2 wires now, for 120v.
I'll need a wire on the other phase to get to 240v.
Please do straighten me out if I'm wrong.
An electrician I am not.
The other question that's arisen overnight is that if I can add a neutral wire that I could have a 14-30.
That seems preferable for several reasons, even if Tesla chargers don't make use of the neutral wire.
14-30 adapters are UL approved, some of the 3rd parties are not. Etc...
I don't quite follow what the neutral wire connects to on the panel unless it's ground.
-R
I'll need a wire on the other phase to get to 240v.
Please do straighten me out if I'm wrong.
An electrician I am not.
The other question that's arisen overnight is that if I can add a neutral wire that I could have a 14-30.
That seems preferable for several reasons, even if Tesla chargers don't make use of the neutral wire.
14-30 adapters are UL approved, some of the 3rd parties are not. Etc...
I don't quite follow what the neutral wire connects to on the panel unless it's ground.
-R
A 6-30 is two hots and a ground. You'd repurpose your existing neutral to a hot.
If UL approval is your concern you should not be doing your own unlicensed, unpermitted electrical work either.
Is your wiring in conduit? If yes, what size conduit, what size wiring, and what is the distance.
DangerRuss
Member
I can try and elaborate:
I'm likely to hire a professional electrician. Just trying to educate myself as much as possible going in.
Electricians seem to be like everyone else, sometimes they're smart and thinkers. They get me to the best option.
Others just blindly do what I ask of them. Prepping in case I end up with the latter.
Don't yet know about conduit (new house).
Starting point is is a 120v TT-30, I now see that it's very likely I can go to 6-30 (without even pulling wire).
That lead me to wondering about how feasible it would be to get to 14-30.
Seems like if I have conduit that there's a decent shot that could be done cheaply too.
I'll find out.
-R
I'm likely to hire a professional electrician. Just trying to educate myself as much as possible going in.
Electricians seem to be like everyone else, sometimes they're smart and thinkers. They get me to the best option.
Others just blindly do what I ask of them. Prepping in case I end up with the latter.
Don't yet know about conduit (new house).
Starting point is is a 120v TT-30, I now see that it's very likely I can go to 6-30 (without even pulling wire).
That lead me to wondering about how feasible it would be to get to 14-30.
Seems like if I have conduit that there's a decent shot that could be done cheaply too.
I'll find out.
-R
Im not sure about your region, but an many places conduit is unlikely. Hence the suggestion for a 6-30.
DangerRuss
Member
That's my assumption too.
I'm presently in Georgia, house is in Virginia.
I think I have a good grasp on what I'm dealing with now.
Thanks all for the explanations and advice.
Great thread.
-R
I'm presently in Georgia, house is in Virginia.
I think I have a good grasp on what I'm dealing with now.
Thanks all for the explanations and advice.
Great thread.
-R
eprosenx
Active Member
Most likely the wire in the wall is Romex (NM-B) 10 gauge. I will assume as much for this post.
So yeah, in the panel you will take the neutral wire that is landed on the neutral bus (likely is common with the ground bus in your main panel) and “permanently relabel” it to black or red in color (e.g. wrap the whole thing in electrical tape). You will re-land it on a new 240v (double wide) breaker along with the existing “hot” wire in the 120v breaker that will be removed (you need one extra breaker panel spot to do this).
On the receptacle end the receptacle will be swapped from the TT-30 to a 6-30. You can’t do a 14-30 without running new wire unless by some miracle they ran an extra conductor already or it is in conduit with enough free space. Make sure to “permanently relabel” the white neutral wire to black on this end as well.
Then yes, you will need a third party adapter that won’t be UL rated. Don’t get me started on how stupid it is that Tesla does not make an adapter for this exact purpose…. (That or TT-30 as others mentioned)
Your plan is solid! Time to go execute!
Feel free to post pictures of your panel and the receptacle and/or the wire itself and folks here can help provide advice on any gotchas (like a 100% full panel - there are often ways around this).
Charge rate on NEMA 6-20 on my Model 3
To my understanding 6-20 means 240v 20A, how come Tesla app or screen showing 16A ?
Mike Hawk
Member
You gotta derate (limit ie lower) a constant amperage draw by 80%, because electrical codes and potential heat build up and stuff. 20a * .8 = 16a
I have a 5-20R outlet in my garage and I hired an electrician to convert it to a 6-20R. I had thought the 5-20R outlet was on a dedicated circuit because it had its own breaker that controlled that single outlet. Unfortunately, the conversion could not be done because our house has a single 4 wire cable from the panel to the garage (hot1, hot2, neutral ground), which supplied the garage 120V 5-20R outlet, and also the laundry room 120V outlet for the clothes washer a few feet away. Even though the washer outlet is a separate circuit/breaker, it shares a neutral and ground with the garage outlet. The electrician explained that I converted the 5-20R outlet to 6-20R, which needs (hot hot, ground) the laundry room outlet would not work. He said that often to save on labor/materials, a single cable run with four wires is used during some home construction to supply two circuits.
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