hungry for amps
February 4, 2010 3:34 PM   Subscribe

DIY: How can I swap my 1500W/220V in-wall space heater with two safe 220V outlets? I am in the state of Oregon and would prefer to do this myself.

The heater in question is on a 'ganged' 20A circuit. As I understand it, this offers me 20A protection across the 220 circuit. I am anticipating load from a small washer/dryer combo that shouldn't exceed 10A on 220. The only other thing on the circuit is another one of these heaters, drawing 1500W. I think the loads will be safe but I don't know the specifics when it comes to installing the outlet.

Most importantly, I want to be sure I am not breaking the law by doing this. I don't know if you have to be licensed to do electrical works in Oregon or if you are required to follow code.

Trying to keep costs down by doing this install myself. I figure if I can reuse the heater circuit I can save installing a brand new one...

Thanks, as always, for your help!
posted by roygbv to Home & Garden (8 answers total)
You want to remove the heater from where it is currently installed and replace it with two 220V receptacles mounted in boxes?

The same sockets as these, American type 220V/30A?
posted by thewalrus at 3:43 PM on February 4, 2010

Whatever type of socket you install, remember the following:

You need a metal bodied box to mount the socket in. The box needs to have a grounding bolt built into its body which you will connect to the ground pin from the socket and the ground wire in the cable coming from your supply.

You can surface mount the box in the location where the heater was formerly located only if any exposed wiring (wires outside of the walls) is protected by conduit that meets code in your location. For example:

If you install a flexible steel conduit between the breaker panel and the box, the conduit needs to make a consistent metal-to-metal connection to the conduit entry hole on the box for grounding purposes. The flex conduit needs to be held securely in its entry hole in some kind of clamp, such as:

The opening point where the cable running inside the conduit enters the box needs to be protected with a plastic sleeve around the cable to prevent damage from chafing.
posted by thewalrus at 3:54 PM on February 4, 2010

The w/d shouldn't or doesn't exceed 10A? What's the rating of it at 220V? You already have a 7A load on there with the heater... Most dryers come with instructions to put them on a separate 30A circuit breaker from everything else. You're also going to want a time-delay c/b for this installation, since the load comes on pretty quickly, making your standard 20A breaker much less than optimal.

I would shy away from trying to make 2 outlets out of one in this case.
posted by squorch at 4:02 PM on February 4, 2010

Response by poster: Good infos. For clarification, the heater is a Cadet wall heater, the 1500W one of these:

The heater enclosure is a metal box (grounded) almost like the heater were a biggie socket. It is attached cleanly to a stud in the wall and can easily be removed, but the wall hole will be larger than any duplex socket. It would be easy to take the heater and heater enclosure out of the wall and be left with a large clean area, mounting stud, and incoming wire.

The wire used for this circuit is the plastic wrapped kind, and looks to be 12ga with three cables in the wrap, two hots and the ground. I think this is called 12/3 wire. It is new looking and clean and could easily be wired into a socket box and socket.

The 220V receptacles can either be a duplex outlet, or two separate single outlets. I think wiring a duplex into a box would be easiest...

It seems like this should go smoothly but is there anything else I am neglecting to think of? Any issues doing the work myself vs having an electrician in? I am confident in my ability as long as I know I am following code, etc.
posted by roygbv at 4:13 PM on February 4, 2010

thewalrus writes "You need a metal bodied box to mount the socket in."

Plenty of plastic boxes are UL/CSA listed for this use. The big problem you are going to encounter is 240V heaters don't require a neutral wire so you don't have one. The wire you describe is 12/2, 12/3 has four wires (generally a black, a red or blue, a white and the uninsulated ground wire). The dryer/washer you are attempting to hook up probably has 120V motors that require the missing neutral. How many prongs on the plug on the washer/dryer?

Canadian Code generally doesn't allow you to share a circuit between hard wired heaters and plug in devices because of how the circuit capacities are calculated. It's not unsafe per se but it's tricky. You can get around this by installing a switch that only powers one device at a time.
posted by Mitheral at 5:13 PM on February 4, 2010

Most importantly, I want to be sure I am not breaking the law by doing this. I don't know if you have to be licensed to do electrical works in Oregon or if you are required to follow code.

Usually homeowners are allowed to do their own work in Oregon but it is always required to be "to code" no matter what. I am an Oregon general contractor (however IANYGC) and the daisy chaining you describe would not fly with Portland inspectors, plus the wire sounds wrong as Mitheral said.

Also you should really just hire an electrician for two reasons.

1: you might kill yourself (220 really hurts!)

2: If you ever intend to sell this house any home inspector will flag this rigged up system. Real estate disclosure laws will require you to admit doing it yourself which will then force you to drop the sale price the exact same amount that it would have cost you now to have it permitted, done and inspected by a pro.

Plus you might burn your house down.

If you are in Portland or near and you want a referal let me know.
posted by ijustwantyourhalf at 9:55 PM on February 4, 2010

Response by poster: Well, this sounds sketchy. I will look into what it costs to have a new circuit off the box - paying to be safe is fine by me. We have quite a bit to work with on the house main so there should be room for improvement.

I would perhaps like to replace the 1500W heater with the 2000W version, as it is old and gross and could put out a little more heat. Anyone see any problem with this? It's rated at 8.4 amps on 240V, whereas the 1500W is 6.25A. Fire hazard?
posted by roygbv at 3:55 AM on February 5, 2010

Replacing the heater should be ok. The total draw of the circuit will be 6.25+8.4 which is well under the 20A your wire and breaker will handle.
posted by Mitheral at 6:20 AM on February 5, 2010

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