Burnt 240V outlet

[SPITmadFIRE]

Edit: just checked the panel and it’s a 50 Amp breaker

Just to be clear, the charger you're using is limited to 30A correct? You're positive the vehicle didn't try to pull too much power? For sustained loads, a 50A breaker should not be used above 40A. The default setting for an R1T is to pull 48A unless the charger properly limits the amperage to less than that.

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[SPITmadFIRE]

Should I have lowered the amperage in the truck? From my understanding, the charger and the truck work together to figure out the maximum it can charge.

If your charger is limited to 30A, it should properly instruct the vehicle it cannot pull more than 30A. You can see this happen if you use the portable charger on a 120V outlet -- the vehicle will automatically limit the current to the max the charger can provide.

This only becomes an issue when you use a charger that can exceed the breaker's sustained rating. When charging off an RV outlet for example, the portable charger will attempt to draw 36A when using the 14-50R plug. If the outlet can only handle 30A and has a 30A breaker, you'll trip the breaker. If the outlet can only handle 30A but the breaker is rated for higher, that's when you run a serious risk of fire and things melting down as your outlet seems to have done.

You should ensure your charger is not trying to draw more power than your outlet is rated for. It's most likely the connections in the outlet have worn down or deteriorated to the point where you got fireworks.

 

[Ngkgb]

Just to be clear, the charger you're using is limited to 30A correct? You're positive the vehicle didn't try to pull too much power? For sustained loads, a 50A breaker should not be used above 40A. The default setting for an R1T is to pull 48A unless the charger properly limits the amperage to less than that.

Yes. It’s 30 Amp and I’m usually charging at 7.1 kw/h so that would mean it’s drawing 30A( 240x30).

 

[SPITmadFIRE]

Yes. It’s 30 Amp and I’m usually charging at 7.1 kw/h so that would mean it’s drawing 30A( 240x30).

Other than the outlet being worn to the point of causing a short or fault, the only thing I can suggest is ensuring the outlet itself is rated for a sustained 30A load. Other than that, where you noticed the fireworks is usually the culprit. If the outlet went up in smoke, you should start by having an electrician examine and replace it. Most electricians provide warranties on their work, unsure how long you've had the outlet installed or if the electrician would provide any guarantee on the work at this point.

 

[dradam]

I am concerned about the connection of your metal clad cable to your metal outlet box. The exposed sharp edges of your flexible metal conduit should be encased in a fmc connector, while it is likely the culprit is the outlet it would make me want to be certain the job is specced correctly. The plug, wire gauge and breaker should all be able to handle at least a 40A rating. 30A EVSE should have 8awg with a 40A breaker. 6awg on a 50A breaker. I would double check everything in addition to upgrading the outlet.

 

[Chrisy]

Yes. It’s 30 Amp and I’m usually charging at 7.1 kw/h so that would mean it’s drawing 30A( 240x30).

For your future reference: as @Zoidz said, you should limit your charging to 24A on a 30A line. Code allows 80% of the rating for continuous load. This should have been in the instructions of your charger (mine had it).

FWIW: I am also using a 30A wires with a 30A breaker and I limit both my charger and the R1T to 24A just to be double sure it does not charger higher than that on a 30A line. Even with this my wire at the breaker box is slightly warmer than the rest when I am charging.

 

[Chris TX]

Looks like improperly torqued outlet terminals. One thing that electricians forget to do is to wait a few minutes and then re-torque. The copper or aluminum will deform after the first torque and it will pull away from the contact surfaces. That second torque is very important.

 

[Ngkgb]

For your future reference: as @Zoidz said, you should limit your charging to 24A on a 30A line. Code allows 80% of the rating for continuous load. This should have been in the instructions of your charger (mine had it).

FWIW: I am also using a 30A wires with a 30A breaker and I limit both my charger and the R1T to 24A just to be double sure it does not charger higher than that on a 30A line. Even with this my wire at the breaker box is slightly warmer than the rest when I am charging.

Other people can chime in, but I don’t believe this is correct. My breaker is 50 Amps and the charger is 30Amps. I believe the 80% rule is for picking the charger. For example the next charger I chose should be no more than 40 Amps. That’s my understanding.

 

[docwhiz]

Charged my R1T today around 11 and around 1 my wife said she noticed a burning smell from the garage. Noticed the charging cable was extremely warm. Checked the outlet and saw the pic below.

For reference, I had an electrician install Siemens 240V/30A charger in 2018. Charged a clarity EV, Etron, Mach E, and R1T fine until today. Though I Should, i dont know the amperage of the breaker. Thats my fault. I just assumed a licensed electrician would choos the right amperage. What does everyone think the most likely culprit of this is? What Shoukd be my next steps?

Thanks

Edit: just checked the panel and it’s a 50 Amp breaker

That's a cheap socket.
Get a Hubbel socket or hardwire.

 

[Riviot]

If you can, I would replace that with a hardwired EV charger. Preferably a 60 amp circuit as well. If not, you can just hardwire up a charger to the 50 amp circuit and eliminate that receptacle.

I second this. If you are against hardwire, at the least get a different electrician.

 

[Zoidz]

Other people can chime in, but I don’t believe this is correct. My breaker is 50 Amps and the charger is 30Amps. I believe the 80% rule is for picking the charger. For example the next charger I chose should be no more than 40 Amps. That’s my understanding.

You initially posted that you didn't know the size of the breaker, so many of the responses were based on assumptions. You then later came back and edited to indicate that it is a 50 amp breaker. With a 50A breaker you can run at 42A.

The heating took place in the receptacle, so the most likely answer is poor termination of the wire to the receptacle, poor quality receptacle, or possibly undersized wire and the wire overheated at the receptacle termination, or a combination of these.

If this is not something you are comfortable doing yourself, I would hire a different electrican, have the whole installation reviewed, and insist on a Hubbell industrial rated outlet. No Amazon/Lowes/Home Depot Chinese crap and no adapters.

 

[JohnB R1T]

I had this exact thing happen. When I took the cover off and pulled the plug out, one of the wires just fell out. It was due to a loose connection, the electrician obviously did not torque it correctly.

Don't be too quick to blame the electrician. Repeated heating and cooling causes expansion and contraction of the wire and the terminals. Over time, this WILL lead to loosening of the connection...particularly where aluminum wire is involved.

The general rule of thumb when tightening a terminal containing larger wire...after making sure that your bare ends are twisted correctly, "bottom" the end of the wire bundle in the terminal and (using the largest screwdriver that will fit in the slot) tighten it as hard as you can. It's a PITA, but it never hurts to come back a few months later and re-tighten it (please remember to flip the breaker "off" first).

 

[Chrisy]

Other people can chime in, but I don’t believe this is correct. My breaker is 50 Amps and the charger is 30Amps. I believe the 80% rule is for picking the charger. For example the next charger I chose should be no more than 40 Amps. That’s my understanding.

My misunderstanding, I thought you have 30A wires between the breaker box and the outlet (on the picture). I should have read more carefully.

If you have 50A wires (6AWG) between the box and the outlet then I was mistaken and you are right you can charge with 30A if the charger says it supports that continuously, mea culpa maxima.

 

[Dark-Fx]

The general rule of thumb when tightening a terminal containing larger wire...after making sure that your bare ends are twisted correctly, "bottom" the end of the wire bundle in the terminal and (using the largest screwdriver that will fit in the slot) tighten it as hard as you can. It's a PITA, but it never hurts to come back a few months later and re-tighten it (please remember to flip the breaker "off" first).

IMO a major contributor to this problem OP is having is trying to use a flat head or phillips head screwdriver to tighten the terminals. They tend to cam-out before you get enough torque on them. The "crappy" leviton 14-50 outlets that people say are problematic will accept a #2 robertson. Basically required to get enough torque on the screw terminals.

 

[JohnB R1T]

You initially posted that you didn't know the size of the breaker, so many of the responses were based on assumptions. You then later came back and edited to indicate that it is a 50 amp breaker. With a 50A breaker you can run at 42A.

The heating took place in the receptacle, so the most likely answer is poor termination of the wire to the receptacle, poor quality receptacle, or possibly undersized wire and the wire overheated at the receptacle termination, or a combination of these.

If this is not something you are comfortable doing yourself, I would hire a different electrican, have the whole installation reviewed, and insist on a Hubbell industrial rated outlet. No Amazon/Lowes/Home Depot Chinese crap and no adapters.

NGKB is correct about 40 amps (it's 80% of 50 amps). A charger is considered a continuous load and calls for the 80% rule (it's in the NEC). 42 won't fly within the code

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