Help: My 50 amp breaker got tripped after 14-50 Nema install

[joebruin77]

Up until recently, I had been charging every day using a Tesla Wall Connector. The plug or handle for the Wall Connector recently got damaged and Tesla is sending me a replacement Wall Connector. But since it will be a while before the replacement Wall Connector can be installed, my electrician yesterday installed a 14-50 Nema outlet. I plan to use the Mobile Connector with the 14-50 adapter to charge temporarily until the new Wall Connector is installed.

The electrician removed the original Wall Connector and put a 14-50 Nema outlet in its place. He did add a neutral wire (since the Wall Connector does not require a neutral line) and replaced the 60 amp breaker with a 50 amp breaker. He used the existing 6 gauge wires that had been connected to the original Wall Connector.

He installed the 14-50 outlet yesterday and I charged the Tesla successfully (at full 32 amps). I left the Tesla plugged into the outlet overnight and unplugged it this morning. I then went out for a bit and I came home 2 hours later. However, when I went to plug in the mobile connector after I got home, there was no power from the outlet. Power to the house was on, so it was not a house-wide power outage or anything like that. I went to the breaker box and discovered that the 50 amp breaker for the outlet had been tripped. I reset the breaker and the outlet once again has power.

I plugged the Tesla into the outlet but reduced the amp setting to 20 amps.

I contacted my electrician. He said that there may have been a power surge and that if the breaker gets tripped again, to not reset it and call him instead. He would then come out and test everything.

Any ideas as to why the 50 amp breaker would have been tripped when using the outlet at 32 amps? Any suggestions on what if anything else I can do to address this?

Thank you!
joebruin77

 

[eprosenx]

Up until recently, I had been charging every day using a Tesla Wall Connector. The plug or handle for the Wall Connector recently got damaged and Tesla is sending me a replacement Wall Connector. But since it will be a while before the replacement Wall Connector can be installed, my electrician yesterday installed a 14-50 Nema outlet. I plan to use the Mobile Connector with the 14-50 adapter to charge temporarily until the new Wall Connector is installed.

The electrician removed the original Wall Connector and put a 14-50 Nema outlet in its place. He did add a neutral wire (since the Wall Connector does not require a neutral line) and replaced the 60 amp breaker with a 50 amp breaker. He used the existing 6 gauge wires that had been connected to the original Wall Connector.

He installed the 14-50 outlet yesterday and I charged the Tesla successfully (at full 32 amps). I left the Tesla plugged into the outlet overnight and unplugged it this morning. I then went out for a bit and I came home 2 hours later. However, when I went to plug in the mobile connector after I got home, there was no power from the outlet. Power to the house was on, so it was not a house-wide power outage or anything like that. I went to the breaker box and discovered that the 50 amp breaker for the outlet had been tripped. I reset the breaker and the outlet once again has power.

I plugged the Tesla into the outlet but reduced the amp setting to 20 amps.

I contacted my electrician. He said that there may have been a power surge and that if the breaker gets tripped again, to not reset it and call him instead. He would then come out and test everything.

Any ideas as to why the 50 amp breaker would have been tripped when using the outlet at 32 amps? Any suggestions on what if anything else I can do to address this?

Thank you!
joebruin77

Very odd. Did he install a GFCI breaker? They are more touchy than regular breakers.

Did you not get a “charging interrupted” message at any point? Most failure modes I would expect would be during operation under high current draws. You should have been notified of an interrupted charge if that was the case.

Do you have any idea at what point the breaker blew? I wonder if it was blown before you left or if it blew when you got back?

This does not seem right obviously...

One possibility would be the wire was not stripped sufficiently where connected to the breaker and insulation got pinched causing it to heat up and blow the breaker. Or the connection to the breaker was insufficiently torqued down.

 

[Adam3]

Is the dial in the wall charger set to 40A?

Edit: nevermind, this is happening with the mobile cable? Weird...

 

[joebruin77]

Very odd. Did he install a GFCI breaker? They are more touchy than regular breakers.

Did you not get a “charging interrupted” message at any point? Most failure modes I would expect would be during operation under high current draws. You should have been notified of an interrupted charge if that was the case.

Do you have any idea at what point the breaker blew? I wonder if it was blown before you left or if it blew when you got back?

This does not seem right obviously...

One possibility would be the wire was not stripped sufficiently where connected to the breaker and insulation got pinched causing it to heat up and blow the breaker. Or the connection to the breaker was insufficiently torqued down.

Thank you for your reply.

I honestly do not know if it is a GFCI breaker or not. I can ask him.

The charging was not interrupted at any point. I was checking the app very frequently and the car charged to 90% with no problems. I know the breaker did not trip during charging because I remember seeing the app indicate that the charging was complete. I do not know if the breaker tripped sometime while the car was still plugged in or if it tripped as I unplugged the car or while I was out (which would be very odd).

If it happens again I will have the electrician inspect everything including the insulation and connections.

 

[Scrannel]

My experience with this install is that the plug from the mobile cable is a tight fit in the outlet, so tight I had to be 100% sure the outlet was seated properly otherwise it would move inward or outward slightly if I plugged/unplugged the connector. Not sure what sort of receptacle you are using but if it "pushed-in" when the cable was plugged in I suppose it might ground fault, then or eventually.

 

[Tessaract]

My experience with this install is that the plug from the mobile cable is a tight fit in the outlet, so tight I had to be 100% sure the outlet was seated properly otherwise it would move inward or outward slightly if I plugged/unplugged the connector. Not sure what sort of receptacle you are using but if it "pushed-in" when the cable was plugged in I suppose it might ground fault, then or eventually.

The way I read joebruin77's post, is that nothing was plugged in to the 14-50 when the breaker tripped. If that's really the case, then the only logical explanation would be a momentary short behind the 14-50, likely due to a pinched wire shorting to the electrical box. If the UMC was plugged in when the breaker tripped, then it could still be a pinched wire, but also a UMC problem. Whichever it was, I would try leaving the circuit without the UMC if the UMC was plugged in during the trip, or with the UMC plugged in if it hadn't been during the trip, and see if the symptom returns...

 

[ZOMGVTEK]

This shouldn’t happen. GFCI’s are uncommon in double pole 50A variants, I wouldn’t imagine he would have installed one due to cost. If it’s a conventional breaker, and it tripping, but resetting and working is concerning. It’s possible a wire is pinched, since it’s very unlikely the car or mobile connector would cause the fault and then still work. A conventional breaker takes much more than its rated current to trip. A 50A breaker may hold 60A for hours. The car won’t draw that much, and if there was a cable fault at those levels for that duration it would be long gone. So the plausible excuse is a fault significantly higher than 50A, or a faulty breaker. Breakers tend to be reliable, so I wouldn’t count on that being at fault.