What am I limited to for EV charging on this sub panel?

[RhondaHonda]

I’m tossing around the idea of an EV for commuter duty. In the garage I’d most likely use, there’s a sub panel 5 feet from where I’d park. The 30 amp compressor circuit goes to an outlet in the basement for a future compressor that I likely won’t ever need. Am I correct that I could just have a 30 amp outlet right next to this sub panel and disconnect the wiring to my downstairs compressor circuit?

I believe this sub panel is limited to 125 amps according to the sticker on the door and has a 100 amp breaker on the panel that feeds it. I’d like 40 or 50 amps for an EV charger but in actuality that isn’t necessary for my current situation.

 

[RhondaHonda]

Higher res images and the main panel.

 

[slacktide_bitog]

How many amps does the EV itself use to charge?

 

[RhondaHonda]

How many amps does the EV itself use to charge?

Well I guess that depends on what I end up with. A Tesla for example, has many options for charging from 15 to 60 amps.

 

[pantygnome]

Did you install the subpanel?

I think first thing Id do is verify correct wiring size into the sub-panel.

 

[Rand]

That panel looks pretty full.
Hate to pop a fuse because 3 things kicked on with your EV charging.

Would also double check the wire gauge for the distance.. (ie the correct gauge for 100amp load at how ever many feet long the run is)
if you are going to be running it near max.

For the actual charger outlet.
I'd want at least 40amp@240v so you could charge at upto 32Amp better would be wiring for 60Amp to charge at upto 50amp.

 

[atikovi]

Am I correct that I could just have a 30 amp outlet right next to this sub panel and disconnect the wiring to my downstairs compressor circuit?

Why disconnect the compressor circuit? Just not have the compressor on at the same time as you are charging the EV.

 

[RhondaHonda]

Did you install the subpanel?

I think first thing Id do is verify correct wiring size into the sub-panel.

No, an electrician did when the addition/garage was added. We went from 400 to 600 amp service at that time.

 

[RhondaHonda]

That panel looks pretty full.
Hate to pop a fuse because 3 things kicked on with your EV charging.

Would also double check the wire gauge for the distance.. (ie the correct gauge for 100amp load at how ever many feet long the run is)
if you are going to be running it near max.

I’ll take a look at what supplies the panel. This is for an addition that is occupied about 20-30 nights a year by my in-laws. It would be be rare that the dryer would be going (maybe 5-10 times a year) and I could just skip charging. I have what I believe is space on the main panels in my house but figured I’d I had an electrician out, I’d have outlets ran to this garage and the main house garage if possible.

 

[RhondaHonda]

Why disconnect the compressor circuit? Just not have the compressor on at the same time as you are charging the EV.

Yeah I guess that would be an option. I don’t have a big compressor and probably won’t so as long as it’s fine by the code, I’d leave it connected.

 

[atikovi]

Yeah I guess that would be an option. I don’t have a big compressor and probably won’t so as long as it’s fine by the code, I’d leave it connected.

When I put my compressor in the basement, I just ran a line from the central A/C unit and told myself I wouldn't use the compressor when the A/C was on. Didn't have to. They run at the same time just fine.

 

[eljefino]

I zoomed in on the labels and those looks like house-living loads. Washer, fridge, microwave. And you've got double-breakers in there, legal, but typically a sign of a panel that's starting to get overloaded.

As others said, it depends on the wire going into the thing. It could be "mobile-home feeder", pretty common for subpanels. You sure can replace your future compressor needs with a local outlet (or hard-wired charger.) Consult with the electrician doing it to see if you can put in a 40 or 50 amp breaker.

You also have to derate by 20% for continuous loads, so a 30 amp is only good for 24 continuous.

You might want to set the car's charging timer to kick on at midnight after the rest of the house starts using less power.

 

[RhondaHonda]

How about this one? Plenty of room even with the sub panel?

 

[RhondaHonda]

Did you install the subpanel?

I think first thing Id do is verify correct wiring size into the sub-panel.

Here’s what was inside feeding it. I’m not sure what size it is but maybe someone here can tell.

 

[JeffKeryk]

Depending on your use case, a 30A service, like a clothes dryer outlet, could work fine.
You are doing it right by figuring out charging first.
I charge with a NEMA 14-50; our Model 3 Mid Range pulls a max 32A.

 

[dlundblad]

He should have used a larger panel for the sub.. would have likely been cheaper than using those twin breakers too. Just seems like an odd thing to do on a home with a 600 amp service. You’re going to have to add more twins to free up 2 spaces for the 2 pole breaker. I don’t like how the sub doesn’t have a main breaker, but that is my personal preference.

Assuming the 100 amp breaker in the main is for the sub panel in question, you’ll be fine. Looks like he used #2 aluminum which is correct for 100 amps. You’ll definitely be pushing it with a 60 amp charger. Don’t run your dryer and charge your car I suppose.

*You have plenty of room in your main panel btw.

 

[mk378]

It looks like the input wires are only 6 AWG. Is the input cable exposed somewhere you can see the size printed on the outside.

 

[ecotourist]

The 30 amp compressor circuit goes to an outlet in the basement for a future compressor that I likely won’t ever need.

I do something like that. I have a 240 Volt 40 Amp circuit for my EV. It's on the same circuit as baseboard heaters that I never use and plan to never use - unless the Heat Pump fails, I run out of firewood and it's below freezing. In which case I won't charge my EV at the same time - I think I can remember to do that.

My Tesla draws a maximum of 32 Amps at 240 Volts so a 40 Amp breaker works.

 

[RhondaHonda]

It looks like the input wires are only 6 AWG. Is the input cable exposed somewhere you can see the size printed on the outside.

I’ll check but I think it’s mostly, if not completely buried behind drywall. Those three wires coming into the panel are thicker than a pencil, if that helps any.

 

[RhondaHonda]

I do something like that. I have a 240 Volt 40 Amp circuit for my EV. It's on the same circuit as baseboard heaters that I never use and plan to never use - unless the Heat Pump fails, I run out of firewood and it's below freezing. In which case I won't charge my EV at the same time - I think I can remember to do that.

My Tesla draws a maximum of 32 Amps at 240 Volts so a 40 Amp breaker works.

If you had a 60 amp circuit would it draw more or is that all it will do?