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

[Nick1994]

Not far, about 8’ on the other side of the sub panel. This is a guest house that gets basically zero usage 90%+ of the year. The dryer definitely wouldn’t be running when I’d be charging. I’ll likely park in the garage attached to the main house most of the time, just like to have options and will probably have more than one EV at some point that we are in this house.

In that case, something like a rotary changeover switch would be a good bet, for either the dryer or compressor line.

Also, the highest you can do on a 30A line is 24A with a Tesla, likely similar for other electric cars. That's to play it safe, the car is smart and knows what kind of outlet it is.

Below is a chart that shows the charging speed on 220v. It is slower for 110v, 110v at 15A for my Model 3 was 3-4 mph.

https://www.amazon.com/Baomain-Universal-Changeover-SZW26-63-Position/dp/B01IZ5ZFYC

 

[KrisZ]

Would using the 30 amp compressor circuit be ok in your opinion? I don’t need a 50-60 amp circuit in that garage for my use. I think I can get 50-60 amps in the main house as one of those panels looks to have quite a bit more room.

If you will use the regular 220v outlet, yes it will work. But if you want to install Tesla charger, you need it on a 50 amp breaker.

 

[RhondaHonda]

If you will use the regular 220v outlet, yes it will work. But if you want to install Tesla charger, you need it on a 50 amp breaker.

That is not what Tesla’s directions say, you setup the breaker size when installing the Wall Connector. I’m fine charging on a 30 amp circuit if the panel supports it. My daily commute is 54 miles total.

 

[KrisZ]

That is not what Tesla’s directions say, you setup the breaker size when installing the Wall Connector. I’m fine charging on a 30 amp circuit if the panel supports it. My daily commute is 54 miles total.

Didn’t know about programming the charger.

If that’s the case then you better make sure it is programmed to the correct circuit breaker. There is no way for any device to detect the breaker amperage.

 

[Snagglefoot]

Before the year 2010, not many builders were putting 50 Amp receptacles and matching wire and breakers in a garage installation. It was much more common to have 10/2 wire and a 30 A breaker usually because the customer wanted to be able to run 220 V air compressor or a home welder.

Looking at chart #61 posted by Nick1994, say with a Tesla 3, moving from 22 mph to 30 mph would not be worth the expense of pulling a shielded cable from your breaker box to the garage, unless you absolutely needed more range than what 8 hrs of charging provided.

Here is what I currently have; a 10/2 cable and 30 amp breaker. The photo is inside the furnace room near the breaker box. The cable runs inside the garage exterior wall which is dry walled and painted. I’m not going to bother to upgrade to 50 amps. When my BIL comes to visit with his Tesla 3 he can suffer with the 30 amp charger then get his rear end to the Tesla super charger 20 miles down the road.

 

[JeffKeryk]

That is not what Tesla’s directions say, you setup the breaker size when installing the Wall Connector. I’m fine charging on a 30 amp circuit if the panel supports it. My daily commute is 54 miles total.

If you have 30A available now, that's sorta OK. Sorta.
If you are considering buying an EV, add the price of a dedicated 50A circuit to your garage.

IMO, this is the cost of doing business. I found some union electricians (their t-shirts logos) eating lunch at Costco. One offered to do the install in his spare time. I got a 50A breaker, 50 to 60' of #6 copper under the house and a NEMA 14-50 for $600 including tip. That's pretty darn good for around here. I did not get a permit...

Good luck!

 

[RhondaHonda]

If you have 30A available now, that's sorta OK. Sorta.
If you are considering buying an EV, add the price of a dedicated 50A circuit to your garage.

IMO, this is the cost of doing business. I found some union electricians (their t-shirts logos) eating lunch at Costco. One offered to do the install in his spare time. I got a 50A breaker, 50 to 60' of #6 copper under the house and a NEMA 14-50 for $600 including tip. That's pretty darn good for around here. I did not get a permit...

Good luck!

The 30 amp is just for that garage, which according to Tesla’s chart shouldn’t be an issue with my usage. I only park there occasionally. It’s probably 50’ or so from the main panel, all behind drywall to that sub panel. The main panel is in the basement garage which is drywalled and the sub panel is in a single upstairs garage also drywalled so I don’t think it’s worth tearing it up.

One of the panels in the main house has what I believe is plenty of capacity for a 50 or 60 amp circuit and it’s in an unfinished part of my basement and adjacent to the main garage. Easy to run 20-30’ of conduit to get more power to that garage. Heck I could do some of that myself to make it even easier for an electrician but it’s probably not worth my time.

Main house panel with space attached below.