60A breaker melted while charging

[West Ridge]

Has anyone had issues with faulty wall chargers that could have caused breakers to literally melt. Truck was set at 48A and was wired to spec. Reinstalled 50A breaker and dialed back to 40A. Breaker still gets slightly warm and very faint buzzing. Wondering if there are faulty wall chargers out there.

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[Electrified Outdoors]

Check for loose wiring. The breaker should not melt...it should trip and stop the current flowing when it heats up too much.

 

[Revelation]

Agree with 240vPlug, likely a loose wire the resulted in arcing. Faulty breaker is possible, but less likely.

 

[azbill]

I had a 50A wall plug (14-50) melt like that. I found one of the hot wires was loose when I pulled the burnt plug from the wall box, that one wire just fell off. The other three wires were all tight. Likely the torque was not done properly on that screw. My breaker did eventually trip, but not until the plug was completely damaged.

 

[mikehmb]

Like @azbill I’ve had a NEMA14-50 melt like that.

Munro did a video where they showed a melted breaker, as well. It’s definitely not supposed to happen.



TL;DR of all of this is that duty cycles for residential applications seems to be inadequate for many charging applications. Get Commercial-rated plugs, if you’re using them, and always always make sure you reduce draw 20% from rated current on a hardwired connection.

 

[mikehmb]

I had a 50A wall plug (14-50) melt like that. I found one of the hot wires was loose when I pulled the burnt plug from the wall box, that one wire just fell off. The other three wires were all tight. Likely the torque was not done properly on that screw. My breaker did eventually trip, but not until the plug was completely damaged.

I had the same failure, with the same loose plug. I believe the heat cycling of the plug is what is ultimately loosening up the contactor, causing it to eventually arc and then superheat and fail.

 

[VSG]

I've had a socket melt from a vacuum cleaner. Point is, this is an electrical issue which just happened to occur on your EV charger circuit, but the problem isn't really about what you had connected to the circuit. My problem was a failed socket.

If something melts, that mean too much current went through it and it got too hot. The breaker is supposed to trip to prevent that, but if the current was diverted before the breaker, the breaker may not see that excess current.

If for example a wire connection is loose, or if the screw is tightened down on the wire insulation rather than the conductor itself (or if many other things), then the resistance at the connection will be high, meaning there will be power loss at the connection in the form of heat. That can be enough to melt things even if the total current never exceeded the breaker's limit.

Breaker getting slightly warm is expected, but buzzing tells me there's something vibrating, which could be an indication of something loose either at a wire connection or internally in a breaker.

If it were a faulty charger I would expect something in the charger would have melted first.

If you had an electrician install the charger, I would have them come out and fix the circuit for you because it appears something was done wrong.

 

[rhesusraider]

To charge at 48A, you would need a 60A breaker and 6 AWG line. That could be the issue. A 50A breaker could support 40A charging.

 

[Revelation]

To charge at 48A, you would need a 60A breaker. That could be the issue.

Based on the way the OP worded his post, I believe he had a 60A prior to the issue. Installed a 50A after and dialed back the charge rate to 40A on the EVSE. I could have misunderstood the OP, but that is my understanding.

 

[rhesusraider]

Based on the way the OP worded his post, I believe he had a 60A prior to the issue. Installed a 50A after and dialed back the charge rate to 40A on the EVSE. I could have misunderstood the OP, but that is my understanding.

Gotcha. That makes sense. Then I would definitely be concerned and thinking about the wiring. I should have read the title more carefully!

 

[CharonPDX]

We had that happen with our very first EVSE - a 32A unit wired to a 40A circuit. The electrician used the existing wiring and breaker (was for a long-decommissioned electric water heater) and apparently it wasn't up to snuff. Had to replace both the breaker and the wiring with brand new.

But apparently the internal arcing damaged the busbar! The new one welded itself to the busbar after a few months. So if we ever need to replace that breaker, we'll have to replace the whole service panel.

 

[TexasBob]

Reiterating what other's have said, we had an overheating plug on a 60A circuit which melted the receptacle, turned out to be a loose wire.

 

[nukem384]

To charge at 48A, you would need a 60A breaker and 6 AWG line. That could be the issue. A 50A breaker could support 40A charging.

You can actually see in the OP post that the breaker is an Eaton Type BR 60a (on the burnt up label "BR 260"). As the other poster mentioned, OP changed it out to a 50a breaker after the fact to get by for now.

 

[Supratachophobia]

Has anyone had issues with faulty wall chargers that could have caused breakers to literally melt. Truck was set at 48A and was wired to spec. Reinstalled 50A breaker and dialed back to 40A. Breaker still gets slightly warm and very faint buzzing. Wondering if there are faulty wall chargers out there.

That my friend, is a loose wire. Who wired it?

 

[nfrank]

It's probably a loose wire, but I've also heard a lot of counterfeit breakers and electrical parts are hitting the market. Make sure you buy the replacement from a reputable parts distributor.

Also, if the wire is aluminum you need to use grease on the connection.

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