MME keeps tripping breaker

[madredhatter]

What's the reasoning for this 40Amp max on a 50amp breaker? I'd like to read more about it. My car can pull 48amps continuously on a 50 amp breaker without tripping it.

You should have a 60 amp circuit for 48 amp charging. Pulling a sustained 48 amp load on a 50 amp circuit is too much and is not in accordance with the EV home charging installation guides.

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[MBCook]

My understanding is it’s electrical codes. A 50A circuit is good for short/intermittent 50A loads. But if you pull 50A continuously (like charging overnight) it heats the wires that would be used with a 50A circuit more than is safe in the wall and becomes a fire risk.

Same reason you can have an 1800W microwave but a L1 charger can’t pull 1800W when charging your car. The microwave won’t be on for hours.

I believe the rule is 80% max amps for continuous use.

 

[ThatGuyLando]

You should have a 60 amp circuit for 48 amp charging. Pulling a sustained 48 amp load on a 50 amp circuit is too much and is not in accordance with the EV home charging installation guides.

Ok that makes sense now that I'm looking at install guide for common EV Chargers, I have a lectron from china and the crappy installation guide never mentioned that . If I can get a return I will since I'm having other problems with it and get a Grizzl-e or a juicebox.

EDIT: Pulled down the charger and set it to 40 amps.

 

[Maquis]

What's the reasoning for this 40Amp max on a 50amp breaker? I'd like to read more about it. My car can pull 48amps continuously on a 50 amp breaker without tripping it.

Here is the NEC code reference:

 

[Old Guy]

I discovered that I can't have the pool equipment (8am-8pm); the dryer; dishwasher; and air conditioner all running at the same time I want to charge the car. I wait until after 8 PM, when the pool equipment is off, and I'm not running the dryer or dishwasher. No problems then.

Let me add that the original wiring of the house was done in 1980.

 

[mkhuffman]

The OP has left the building.

 

[ChuckA]

I discovered that I can't have the pool equipment (8am-8pm); the dryer; dishwasher; and air conditioner all running at the same time I want to charge the car. I wait until after 8 PM, when the pool equipment is off, and I'm not running the dryer or dishwasher. No problems then.

Let me add that the original wiring of the house was done in 1980.

What amp service does your 1980 electrical have? If you have only 100 amp service, using 50A on an EVSE during the day is a problem. Unless someone works nights, it’s wise to always charge off-peak, 8 pm to 7 am.

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