Basic question about 80% loading of breakers

[Mike1903]

Looking into EV chargers, I saw that a 48a charger should be on a 60a breaker to stay below 80% loading.

How does that apply to 15a/20a breakers? Does it mean that max continuous current out of those should be 12/16A?

Thx

 

[sparky 1971]

Continuous loads are for three hours or more and the rule applies to all sizes of circuits, including 15 and 20's. Contrary to what many people think, a breaker isn't going to magically trip if run at 100% for three hours and one minute.

 

[jeepxj]

correct. 80% applies to them that way. plugging into a regular 15a wall outlet is a slow 12a charge.

 

[beemerphile]

correct. 80% applies to them that way. plugging into a regular 15a wall outlet is a slow 12a charge.

While I am building my new house, the Tesla has to charge from the temporary power pole on a 20A breaker. That nets about 4 miles per hour of charge. I have a 48A charger (on a 60A breaker) in the new garage waiting for county approval for permanent power.

 

[jeepxj]

While I am building my new house, the Tesla has to charge from the temporary power pole on a 20A breaker. That nets about 4 miles per hour of charge. I have a 48A charger (on a 60A breaker) in the new garage waiting for country approval for permanent power.

in the south a normal 15a outlet will yield enough charge for the avg US commute. in the north during the winter it will barely be able to keep the battery warm enough to charge. it has to keep the battery above freezing to dump juice into the pack. some nights you will net negative battery level.

 

[beemerphile]

in the south a normal 15a outlet will yield enough charge for the avg US commute.

At my advanced age, I only commute to doctor's appointments. I have a Honda Ridgeline and an old Tacoma if the Tesla needs to sit and charge. I'll be glad when the Tesla Wallcharger is in operation.

 

[dcg9381]

While I am building my new house, the Tesla has to charge from the temporary power pole on a 20A breaker. That nets about 4 miles per hour of charge. I have a 48A charger (on a 60A breaker) in the new garage waiting for county approval for permanent power.

You should have installed a Siemen's Talon box on the temp pole. Under $200 for the box. It's got a 14-50R, 30A, and 20A GFCI.

 

[beemerphile]

You should have installed a Siemen's Talon box on the temp pole. Under $200 for the box. It's got a 14-50R, 30A, and 20A GFCI.

That is what I have, but I am using the 14-50R to power my 36 ft, 5th wheel which is our temporary home during construction. The other circuits are being used as construction power.

 

[dcg9381]

That is what I have, but I am using the 14-50R to power my 36 ft, 5th wheel which is our temporary home during construction. The other circuits are being used as construction power.

The Siemens box I mention has RV 30A and 50A. It looks like you're farther north than me, so you could probably get by with 30A power on that RV and use the 50A for a level 2.

Here's the other thing, I have a "splitter" for my 14-50R. As those circuits/receptacles typically provide (240V * 50A * 80%) 9.6KW continuous, your RV is probably pulling about half of that with both ACs on. Using a splitter, you can power up a level 2 charger, you'd just need to set the rate down to 25A or something reasonable. Sounds like you charge at a rate of 12 miles per hour or better... You could the rate up depending on what you're actually using in the RV.