Derating of the 80 Amp Charger

[merek]

I was reading the instructions for the 80-amp charger, and I know you can derate it -- but it's not really clear if you can use thinner wire if you derate it? It is showing input wire requirement of 3AWG, and don't mention derating it in relation to wiring size. I am assuming if you derate it, you can derate the wiring as well?

Not really sure if it's a code thing because the charger is technically capable of 80 amps or not.

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[FlasherZ]

Yes, you may use smaller conductors if you use the switch internally to lower the maximum current.

Note that the latest version of the NEC makes a distinction between which mechanism is used to lower charge rate. The switch inside the unit must be used if you plan to use a smaller conductor. Configuration options which are easily accessible to the user of the device don't qualify.

 

[Lightning.Dav]

Will you also need a smaller circuit breaker?

 

[Whammy Bar]

Will you also need a smaller circuit breaker?

The circuit breaker protects the wire, so if you downsize the wire, you'd need to also adjust the circuit breaker sizing.

 

[jefro]

You could install the charger at any rated current setting and then derate the charger I supposed but kinda silly. You have to follow the installation manual also to see how it says to install it. I have an switch adjustable EVSE that I've set lower and used smaller wires and circuit breaker, wires and circuit breaker for that setting. I can easily charge at much lower current than maximum. I could maybe get buy with 16A@240VAC overnight.

Easier to pull the smaller wires and less cost overall.

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