Have 14-50R for Model S, 10-30R for dryer; way to use 6-30P space heater?

[brec]

This is sorta off-topic, except that the motivation is to be able to use a 240V space heater in my garage so that I can rinseless-wash my Model S in the winter without too much discomfort. All I know about electricity is that electrons are yellow, and I figure that those of you who know more would check this forum.

The garage's inside access is to the laundry room, which has a 10-30R for a dryer. I could run an extension cord from that. And there's a 14-50R in the garage which I had installed for charging the Model S. To provide sufficient heat I've been assuming I need a 240V space heater; the portable ones I see on Amazon have 6-30 plugs. Would there be any economical solution to powering one of them in my garage?

 

[FlasherZ]

The first question I would ask is whether you ever intended to heat the garage at the same time you charge the car and/or dry clothes with the 10-30 in the laundry room.

If no, and you were thinking of using the 14-50 for it: in theory, you could use a section of 6/3 rubber cord and a 14-50P attached to a 30A fused air conditioner disconnect, then a section of 10-3 rubber cord from that to provide a properly-protected 6-30R to the space heater cord.

If yes, run a new 30A circuit with 10/2 NM cable, and install a 6-30R from the panel.

I would not recommend using the 10-30R, or trying to extend its circuit. This is because a 10-30 is typically run without an equipment grounding conductor (aka ground). Older appliances grounded through the neutral, but this practice was eliminated in the 1990's and all new construction since NEC 1996 required NEMA 14 series receptacles.

 

[SomeJoe7777]

I agree with Flasher, there's no easy way to do this other than a 14-50P plug on 6/3 cord going to a box that has a 30A protection device and the 6-30R outlet.

It's tempting to say you can make a simple cord that would allow you to plug the 6-30P into the 10-30R outlet, but that's not at all to code. The 10-30R's 3rd pin is a neutral, the 6-30P's 3rd pin is a ground. Depending on the system the building has installed, this could be dangerous.

 

[grichard]

Can't you just use the car? Plug it in, turn up the heat, open doors/windows?

 

[wws]

Could the 10-30 in the laundry room be easily updated to a 14-30? (E.g., are all four wires present in the junction box, but only three are being used? Or is it very close to a panel or subpanel so an upgrade would be easy?)

 

[brec]

Thanks for the ideas, suggestions, and analysis. I should have noted that there's not a need for simultaneous use of the heater and car charger.

The electrician who installed my 14-50 quoted $230 for a 6-30R installation. The alternative, FlasherZ's 14-50P to 30A protection to 6-30R, is a DIY project that I'll look into -- probably starting with a visit to Home Depot.

 

[GSP]

Thanks for the ideas, suggestions, and analysis. I should have noted that there's not a need for simultaneous use of the heater and car charger.

The electrician who installed my 14-50 quoted $230 for a 6-30R installation. The alternative, FlasherZ's 14-50P to 30A protection to 6-30R, is a DIY project that I'll look into -- probably starting with a visit to Home Depot.

$230 for a properly installed dedicated 6-30R circuit sounds like a much better deal than lashing up a homemade adapter/extension cord. Espically considering that the latter requires unplugging your UMC and plugging in the adapter, and visa versa, every time you want to turn on the heat. If you do go that route, I recommend turning off your 50 A breaker when unplugging and plugging into your 14-50 outlet.

GSP

 

[brec]

Yeah, the dedicated 6-30 does seem like the way to go.

 

[davewill]

The parts for the adapter will easily be $70-100. At that price, I'd have scheduled the outlet install on the spot.