Can I use a SPDT?

[mrVanagon]

Greetings all. I have a finished attic with a bedroom that gets warm in summer and cool in winter. I have wired in a single device receptacle near the window to plug in a 120v window AC unit in summer. This is fed by a 20a breaker and 12awg wire in conduit up to the attic. There is nothing else on this circuit. In the winter we stow the window unit and use that outlet to power a quartz space heater. I'd like to install an electric in-wall heater but pulling another wire to the attic would be a real pain. I would prefer to add another circuit for the attic in the existing conduit but it isn't big enough for that. Can I rewire this attic circuit with a SPDT switch so that one position powers the proposed in-wall unit and the other powers the receptacle for the window AC?

Any input is appreciated.

 

[James-W]

I am not an electrician, but I don't see why not, as long as the switch can handle the load.

 

[wyliesdiesels]

Why do you need a switch?

 

[James-W]

I am assuming he doesn't want the possibility of having more than one thing running at a time. Having the switch means that at any given time only one outlet has power going to it, which is what he wants. At least that is the way I understand it to be.

 

[ard]

Let's say you have 2 appliances to plug in, each drawing 15A

And you plug them into the same circuit.

Do you need a SPDT to prevent them from drawing too much? No, the breaker will protect you....

Having said this, there is an issue of 'does the Code permit a specific install'. I think we need a bit more info.

OP has a single outlet Dedictaed branch circuit for the AC.

He wants to install an (assumed) direct wire in wall heater.

OP- a few questions:

How much current will the AC draw?
Is it a plug in with a 15A plug?
How much will the Heater draw?
How is it wired? Any specific wiring instructions for this unit?

 

[PhysicsDude]

FYI: A standard 3-way light switch is a SPDT switch. I've used them before for similar applications. Make sure you get one rated for 20A.

 

[75gmck25]

From an electrical switch standpoint, its easy to install a switch that goes between a hard-wired heater and a plug-in A/C unit. However, it may be a little confusing, which is why I expect there may be code that prohibits switching power on a single circuit between hard-wire and plug-in.

Bruce

 

[mrVanagon]

Thanks for the responses all. Let me clear up what I was actually thinking. I currently have a dedicated circuit for a plug-in AC unit. This thing is small (8000BTU if I recall correctly) and uses about 8 amps @120v. I want to add an in-wall heater that is direct-wired. I was considering using a 3-way switch to allow me to power either the existing out/AC or the future heater. My thinking was that I didn't want the possibility to power both at the same time. On further thought, that would be extra complexity for little benefit. If I wired both that outlet and a new heater to that 20A breaker, it would trip if both units were turned on at once.

On further research, I've decided to **** it up and pull another run of romex up to the attic to power a 2000 watt heater at 240v. This will let me have more heat output, run the heater less often and use fewer amps in the process.

Thanks again for the responses.