Suitability of NEMA 14-50 for EV charging -- Child Safety & Thermal Cutoff

[don_resqcapt19]

My opinion is that receptacles in general need to be made better and have a more rigorous product/testing standard. If I think about all the "burnt up" stuff I have seen in my career, probably 95% of them have been receps.

How much from misuse or just old worn out receptacles, and how much from poor installation practices?

 

[brycenesbitt]

If the initial failure begins where the branch circuit conductors are attached, it may be too late by the time the plug sensor can detect it.

What do you suggest instead? The plug sensor might not prevent a melted plug, but could prevent a fire.
Note the J3400 or "Tesla" connector even uses temperature sensors to regulate current. The thing stuffs in more amps until the connector gets to temperature then levels off or backs off as needed. Pretty slick. The advantage of using the EVSE for things like this (compared to a dumb breaker or whatever) is that it knows all the electrical parameters: current, voltage, temperature.... and can adjust the current limit rather than just shutting off.

 

[retirede]

What do you suggest instead? The plug sensor might not prevent a melted plug, but could prevent a fire.
Note the J3400 or "Tesla" connector even uses temperature sensors to regulate current. The thing stuffs in more amps until the connector gets to temperature then levels off or backs off as needed. Pretty slick. The advantage of using the EVSE for things like this (compared to a dumb breaker or whatever) is that it knows all the electrical parameters: current, voltage, temperature.... and can adjust the current limit rather than just shutting off.

I don’t have a better suggestion for detecting an overheated plug/receptacle. And I’m not saying the temp sensor is a bad idea, just that it’s not a panacea.

My Ford Mobile Charger has a sensor in the 14-50 plug that throttles charging once the temp rises above some threshold as you describe. My Ford vehicles have a sensor in the charge port that does the same thing.