Is my NEMA 14-50 Outlet Getting Too Hot with EV Charger?

[ghsnick!]

I have a Legrand NEMA 14-50 Outlet and an Electrify America HomeStation.

I have a 50A GFCI Breaker and the charger runs at 40A max. The operating temperature of the charger says up to 122° F and while it says it shouldn’t be on a GFCI Breaker, I have to have that in my garage due to code and have only experienced 2-3 false trips in a year.

It’s been working great for a year, but I wanted to see how hot it was getting. I noticed at the outlet, the left side was 127° F, the right side was 111° F, the top was 105° F. The wire going to the charger was 114° F, the top of the breaker was 131° F, and the bottom of the breaker was 91° F.

This has been working perfectly for a year, no signs of anything dangerous about to occur. Just wondering if this is concerning or if this is working how it’s supposed to.

Thanks!

 

[beatle]

That's pretty toasty. I eventually melted my (crappy) Leviton 14-50 receptacle by charging at 40A on a gen1 UMC. Not sure if your EA connector has a thermistor in the plug or if its thermal protection is limited to the internals. The gen1 UMC doesn't have a thermistor in the plug, and eventually it melted the plug so much that the car errored out while charging.

Eventually your breaker will trip from heat as well. Shortly after I replaced my receptacle, I found my breaker was tripping from heat. I think it was in the 170 degree range, measured right at the contacts. I pulled it out and cranked down on the lugs, then checked temperature again - it then only got to about 90 degrees.

All of this happened after 29 months of routine charging at 40A. I now charge at only 32A most of the time, and my Utilitech 14-50 and replacement UMC 14-50 adapter is fine after 2 years.

 

[ItsNotAboutTheMoney]

On a Bolt forum thread in 2019 How hot is too hot for a 40A breaker? somebody posted information from a 2011 UL standard:

The acceptable operating temperature of a circuit breaker is defined by UL in the UL489 standard (June 2011), which is listed below.

• Terminations for standard rated breakers: UL 489 Paragraph 7.1.4.2.2 says the temperature rise on a wiring terminal at a point to which the insulation of a wire is brought up as in actual service shall not exceed 50°C (90°F).
• Terminations for 100% rated breakers: UL489 Paragraph 7.1.4.3.3 says the temperature rise on the termination shall not exceed 60 deg. C (108 deg. F).
• Handles, knobs and other user surfaces: UL489 Paragraph 7.1.4.1.6 says the maximum temperature on handles, knobs, and other surfaces subject to user contact during normal operation shall not exceed 60°C (140°F) on metallic and 85°C (185°F) on nonmetallic surfaces.

So the breaker temperatures are too high. Might want to lower to 32A and get it checked out.

 

[ATPMSD]

You need to check the connections on both the outlet and breaker, make sure they are tight. It is not uncommon for connections in an outlet to become loose over time if they were not properly torqued in the first place. This will cause overheating of both the outlet and breaker.

I have no idea as to the quality of the outlet you have, general consensus around here is to use a Hubbell or Bryant outlet. You are correct that you cannot remove the GFCI breaker as it is required by code. The only way this can be done is if you hardware the “homestation” to the circuit. You may wish to see if this is an option especially as the wire from the unit to the outlet seems a little tight to me.

 

[Earl]

On a Bolt forum thread in 2019 How hot is too hot for a 40A breaker? somebody posted information from a 2011 UL standard:

The acceptable operating temperature of a circuit breaker is defined by UL in the UL489 standard (June 2011), which is listed below.

• Terminations for standard rated breakers: UL 489 Paragraph 7.1.4.2.2 says the temperature rise on a wiring terminal at a point to which the insulation of a wire is brought up as in actual service shall not exceed 50°C (90°F).
• Terminations for 100% rated breakers: UL489 Paragraph 7.1.4.3.3 says the temperature rise on the termination shall not exceed 60 deg. C (108 deg. F).
• Handles, knobs and other user surfaces: UL489 Paragraph 7.1.4.1.6 says the maximum temperature on handles, knobs, and other surfaces subject to user contact during normal operation shall not exceed 60°C (140°F) on metallic and 85°C (185°F) on nonmetallic surfaces.

So the breaker temperatures are too high. Might want to lower to 32A and get it checked out.

From this info (if true), we'd need to know what the ambient temperature is before we'd know if there is a problem. The temperature above are a 'temperature rise', not an absolute temperature.
However, given the, the 122° F limit in:

The operating temperature of the charger says up to 122° F

Would be the maximum ambient temperature.
From both, we'd see that the maximum absolute temperature of the wiring terminal at the breaker would be around 162° F. The plastic knobs shouldn't exceed 185°F .
This would suggest there isn't a problem.