Charging Infrastructure Question - 240V out of AC circuit?

[Pilot1226]

Hi all,

I have an old house. I'm looking for a way to tap into, so to speak, the 240V line that is running my central AC.

My panel is fully maxed and subpaneled. There's nothing else to do except replace it when it comes to adding 240V.

I have gas appliances: stove/range, dryer, hot water, steam boiler. Nothing's pulling big on electric. House has been converted 100% to LED lights.

Ideally, what I'd like to do, is have an electrician install a 14-30 line from the existing line that feeds the AC compressor. This appears to have its own individual 50A subpanel in my wall.

I'd like to have the 14-30 wire run to the side of the house so it's easily accessible from the driveway where I park. I would plan on using this outlet in colder months (September through April) when the central AC is not being used. During the summer months, when my car is not driven as much, I will use a 5-20 outlet in my garage or consider "moving" the outlet outside for easier access.

I've included a couple pictures for your review. The quote from multiple electricians has been in the ballpark of $2000-2500. This would be somewhere closer to the $750 range, if possible. I'd then reclaim almost all of it through state incentives.

What is the best way to have this done? I am happy with having some type of transfer switch setup on the outside of the house where the wire feeds into what looks like a breaker for the condenser. I could ask that they replace the AC subpanel with the extra breaker for the EV charger but I think that would be potentially bad, as there would be nothing to stop someone from running all things at once.

Thanks.
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[Rshephorse]

Don't you have a 240 circuit open from a previously electric appliance?

 

[Rshephorse]

Don't you have a 240 circuit open from a previously electric appliance?

I've got a circuit open from our now gas oven that I'm going to use.

 

[Pilot1226]

Not that I can tell. Looks like things have been changed over the years. We’ve only been here for about 10 and things like that are the same they’ve been.

 

[jmaddr]

Have the electrician take stock of what you have now, find out if you have unused circuit breakers. You didn’t mention the size of your main and sub panels and that information will factor into where there might be 24A-48A available for a dedicated 240V charging circuit. I wouldn’t think with primarily gas appliances you should have much issue finding room unless your main is small. I also am weary of any “double-tapping” of your AC line. 240v circuits like that should be dedicated. You night be able to replace a few of the the 20A/120V with double breakers to free up space.

 

[Pilot1226]

Sorry, I'll try to get a couple pics of the main box, they came out blurry for some reason.

I don't think I'm anywhere close to the maximum amperage, but I don't think they have room to really add another circuit, and that's my problem.

I look at the 240V 50A subpanel for my central air to be "inactive" for 9 out of 12 months of the year, and I can easily use this available amperage and circuit as needed for a meager 6-20 or 14-30 outlet in the winter time. I just have to figure out a way to make that happen.

All 3 of the electricians looked at it and basically said "new panel" but kind of said that before I even was able to describe what I wanted to do here. I'm sure it's a big money maker for their company compared to just doing some labor & subpanel work.

Here's my setup:

100A main panel with 2 50A fuses on right side, left side has a bunch of 15 & 20A circuits. One of the 20A circuits is "inactive" as it is a whole house fan that isn't use anymore. I can turn this circuit into anything, but for obvious reasons I'd want this to be a 6-20 or a TT-30 RV outlet, or, worst case scenario, a 5-20.

50A subpanel to central air: handler on a 20A circuit, condenser on a 30A circuit.

50A subpanel to "expand" the main breaker panel: has a variety of outlets for basement, garage, kitchen, bathroom on top floor, bathroom on main floor.

Again all lights in the house are LED's so they don't use much juice, and my appliances are all gas. Nothing special here.

 

[Pilot1226]

I wonder if something like this would work. I would have to figure out a way to use it with the air on one side and the charger on the other.

NeoCharge 240V smart splitter allows extra EV charging without expensive wiring - Electrek

 

[MNmark]

I'm not an electrician but I would say any of your 3 panels would do to tap into. If you have room in the panels for wiring but all the breaker spaces are taken, then do as jmaddr suggested and use a couple of tandem breakers to free up two slots for a new 240 circuit. It will probably be easier to replace the air conditioner sub panel rather than modify the existing one. If you do tap into the the ac panel, you will need to limit the charging rate in the summer so as not to trip the 50 amp breaker when your ac unit is running. Outside the air conditioning season, you should be fine.

 

[Nakk]

You can't tap into a circuit that feeds a hardwired appliance. It's against code to have an outlet on that circuit for a variety of very good reasons. The load splitter mentioned above is for an an outlet powering something like a dryer. It prevents you from using both at the same time. That seems like it would work as you're not drying clothes in the middle of the night and you could schedule your EV charging then. I'd make sure anything like that was UL approved before I would use it though.