Home Charger Wiring, Does This Work?

[Ladiver]

I am not an electrician but will hire one to do the job. I am just curious if this wiring would work or if I need another selector switch? Can you even have a 14-50r on a 60A breaker? NO I know I could not use the outlet and the wall charger at the same time. They would not be. The outlet would be installed first with the wall charger added at a later date.

Using 4AWG from a 60A 50A breaker to safety cutoff to J box where two sources go out to the Rivian Wall Charger and a NEMA 14-50 receptacle?

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[Ladiver]

Found my own answer, I can not use a 14-50r with a 60A breaker. So, the next part in question is the junction box. Can a 14-50R or wall charger connect in a junction box, or does the wire need to go all the way back to the breaker?

 

[Joneholland]

You need to be a dedicated circuit for both. You can’t have an outlet and hardwire to the box. This won’t pass inspection anywhere.

 

[AdamsFan1983]

no; the charger requires a dedicated 60 amp circuit. Additionally, the charger does not take 4 wires- you don't need the neutral. It requires 2 hot wires and a ground.

 

[ajdelange]

To do what you have pictured you will need a 100 A breaker in your main panel wired with AWG 3 to a sub panel in the garage. The sub panel has 2 breakers 50 A each, one to the EVSE and one to the 14-50R. The EVSE must be commissioned for a 50 A breaker meaning max charging rate of 40 A.

For 50A charging you would need a 110 A breaker in the main panel with 50 and 60 A breakers in the sub panel and larger wire to the sub panel. Then the EVSE can be commissioned for a 60 A breaker and 48 A max charge rate.

 

[Ladiver]

Thanks for the comments. That is about what I was expecting. I ask an electrician about getting the 110A to a garage subpanel. At that point, I can wire the EVSE and the outlet directly to the dedicated breaker. No need for a power disconnect as that can be handled at the breaker.

 

[jphillips97]

To do what you have pictured you will need a 100 A breaker in your main panel wired with AWG 3 to a sub panel in the garage. The sub panel has 2 breakers 50 A each, one to the EVSE and one to the 14-50R. The EVSE must be commissioned for a 50 A breaker meaning max charging rate of 40 A.

For 50A charging you would need a 110 A breaker in the main panel with 50 and 60 A breakers in the sub panel and larger wire to the sub panel. Then the EVSE can be commissioned for a 60 A breaker and 48 A max charge rate.

If he is only going to use one at a time, he could have a 60A breaker in the main feeding a sub panel with a 60A and a 40A. You do not have to sum the down stream breakers....

 

[Ladiver]

If he is only going to use one at a time, he could have a 60A breaker in the main feeding a sub panel with a 60A and a 40A. You do not have to sum the down stream breakers....

That makes life much better.

 

[timesinks]

If he is only going to use one at a time, he could have a 60A breaker in the main feeding a sub panel with a 60A and a 40A. You do not have to sum the down stream breakers....

No, but you also don't get to rely on a pinky swear that you won't use both at the same time when you're sizing the feeder. There is a formula. It's complex. You could use an interlocking device or load management system to justify a smaller feeder, but otherwise, you need to use at least what the formula spits out.

 

[Ladiver]

No, but you also don't get to rely on a pinky swear that you won't use both at the same time when you're sizing the feeder. There is a formula. It's complex. You could use an interlocking device or load management system to justify a smaller feeder, but otherwise, you need to use at least what the formula spits out.

I was thinking something like an A/B switcher which would isolate the power to only one device or the other.

 

[timesinks]

I was thinking something like an A/B switcher which would isolate the power to only one device or the other.

Look at Dryer Buddy (https://www.bsaelectronics.com/collections/dryer-buddy-plus-auto). You could also look for a double-throw safety switch. But I think you mentioned hiring an electrician for the work -- tell them what you want to achieve, what you're thinking, and ask for their recommendation on how to handle it.

 

[jphillips97]

No, but you also don't get to rely on a pinky swear that you won't use both at the same time when you're sizing the feeder. There is a formula. It's complex. You could use an interlocking device or load management system to justify a smaller feeder, but otherwise, you need to use at least what the formula spits out.

You have a 200A service at your house.... Add up all the other breakers.... Likely more than 200..

The first 60A breaker protects all the common wire leg. The sub panel 60A breaker protects its wires... The subpanel 40A protects its wires... If you use both at the same time the 60A in the main panel pops... No pinky swear required... Not complex math at all.

 

[timesinks]

You have a 200A service at your house.... Add up all the other breakers.... Likely more than 200..

The first 60A breaker protects all the common wire leg. The sub panel 60A breaker protects its wires... The subpanel 40A protects its wires... If you use both at the same time the 60A in the main panel pops... No pinky swear required... Not complex math at all.

Actually, I have a 400A service split across 2 200A panels.

You are right that the service is not sized by adding up all the branch circuit labels. But that doesn't mean you can do whatever tf you want. NEC 215.2 discusses the minimum rating and size of feeders.

And, as a rule, these things are sized using a belt and suspenders approach. You should never be relying on the breaker alone to pop (breakers fail). Instead, circuits are sized for their designed loads (this is your belt) and breakers are added to kick in when the system isn't behaving as designed (this is your suspenders).

But don't take my word for it. Let's hear what @Ladiver reports back after discussing it with a professional.

 

[jphillips97]

Actually, I have a 400A service split across 2 200A panels.

You are right that the service is not sized by adding up all the branch circuit labels. But that doesn't mean you can do whatever tf you want. NEC 215.2 discusses the minimum rating and size of feeders.

And, as a rule, these things are sized using a belt and suspenders approach. You should never be relying on the breaker alone to pop (breakers fail). Instead, circuits are sized for their designed loads (this is your belt) and breakers are added to kick in when the system isn't behaving as designed (this is your suspenders).

But don't take my word for it. Let's hear what @Ladiver reports back after discussing it with a professional.

I will certainly be interested in what he hears, but it is very common to have the sum of down stream breakers exceed the feeder breaker. The requirement is that the breaker be sized for the wire it is protecting.

Cheers

 

[Ladiver]

I think @jphillips97 is not wrong with what can safely be done, but I also think @timesinks makes the point that the NEC does things a little differently. As soon as I talk to an electrician, I will let you both know who is right!

I suspect, as with everything, the truth will be somewhere in the middle.

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