Radiant heat question

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Old 01-08-10, 03:15 PM
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Radiant heat question

My parents just bought a 3 bedroom 1970's house with electric ceiling radiant heat. As this type of heat is very inefficient, they want to use small wall mounted space heaters instead. Only problem is the bedroom outlets are on one 15A breaker. When running the small heaters in two rooms, the breaker trips.

In the master bedroom, they've been connecting the heater to the bathroom outlet, which is on a different circuit but this doesn't solve the problem in the other 2 rooms. I removed the wall mounted radiant heat thermostat and in the metal box saw 2 Romex cables connected to each other, the radiant heater wires, and the thermostat wired to switch the power on/off (very basic wiring). Since there were 2 neutral wires (connected to each other), 2 hot wires (also connected to each other), and 2 radiant heat wires (one to hot, one to the T-stat), I'm assuming this is a 120v circuit. The Romex appears to be 10 ga (2 wires plus bare ground).

Is there any reason the thermostats can't just be removed and replaced with a regular outlet so the space heater could just be plugged into the old radiant heat power supply? This would eliminate the overloading problem and essentially provide the heaters with their own circuit.

Thanks for any help.
 
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Old 01-08-10, 04:13 PM
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Don't "assume" anything with electrical wiring!

This whole situation sounds quite dangerous to me. This could result in a fire or electrocuition.

I would suggest your parents hire an electrician to properly add new circuits for the electric heaters.

And then if you want to work on electrical wiring, usually you are only allowed to work on your own house if you are not an electrician.

I would suggest getting a book on electrical wiring at a home improvement store and reading it cover to cover. Then you will be familiar with the basics and the dangers of electrical wiring.

Learn how to use a multimeter...
how to use a multimeter - Google Search

Then before doing any electrical wiring, get an electrical permit from your city or county - this allows you to do electrical wiring. You tell them in advance what you plan to do. They can warn you if it is dangerous. Then they come and inspect your work to be sure it is safe.

I'm sorry if I sound "harsh", that is not my intention. I feel people should have some minimum level of learning before attempting to do any electrical wiring. This stuff can be quite dangerous!
 
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Old 01-08-10, 04:54 PM
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Bill. I know how to use a multimeter, thanks. With only 2 conductors (white/black) with common neutral and a single switched hot how could it be anything but a 120v circuit? It just surprised me radiant heat was 120 v 240, I thought it would be 240 due to the reduced current requirements. Also, what about this sounds dangerous to you? I'm just trying to understand your seemingly panicked reply. Telling people "electricity is dangerous, hire an electrician" does little to help anyone understand their situation. We don't need a forum for that...

I'm quite familiar with the dangers of electrical wiring. I've replaced outlets, switches, GFI's, vent fans, as well as eliminated a lot of previous owner's improperly done wiring in the house. While replacing the outlets I also took the additional time to wire them all to the side-screws instead of the back-stab connections due to their propensity to fail or create a hazard. I was truly amazed how many wires just popped loose when I pulled the original outlet away from the wall. The old owners used electrical tape and extension cords for everything from the fountain out front to the yard light in back, which has since been removed. And don't get me started on the buried Romex to the pool area.

I understand the "best" way to add a circuit for the heaters would be to run new dedicated cable to the panel but I'd rather use the existing wiring that's already there if it will safely accomplish the same thing. Plus there aren't any empty spaces in the panel and I'm not about to replace the panel just because. If the wiring is already there and capable, I'm more looking to understand the code requirements concerning using this existing circuit, i.e. the 10 ga wiring, like changing out the breakers, adding GFIC protection, etc.

Also, where in the code does it state you are only allowed to work on your own house? I can understand limitations placed on working for hire or on publicly accessible buildings without a contractors license but do you mean I can't replace a family member's light switch without one. Where does it say this? My hunch is it doesn't.
 
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Old 01-08-10, 05:29 PM
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With only 2 conductors (white/black) with common neutral and a single switched hot how could it be anything but a 120v circuit?
Black and white can also be a 240v circuit. True in a perfect world the white would be remarked some other color but often it isn't. Not sure what a common neutral but the thermostat on a switched 240v circuit can be on only one leg so a continuous white which is not a neutral and a switched black is not uncommon on a 240v circuit.

Above assumes in location "Ca" is California not Canada.
 
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Old 01-08-10, 05:30 PM
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BTW: You ARE asking first, so that is a very good thing!

As to what you are allowed to do or not do, that is up to the local electrical inspector's office. This is different in each area of the country, so best to get it straight form the "horse" and ask them.

In some areas you can't work on anything, others your own house only, others they require you to take a test on the basics of electrical wiring. Others???

As to the white/black and being 120 volts, people don't always wire things as they should. This could be a 240 volt circuit even though it has white and black wires.

You can check it with a voltmeter.

And check it by finding the circuit breaker. Seeing if it is a double breaker.

Also sometimes these heating circuits have "contactors" in the mix. This would be a "relay" basically. If you have this, it would be in a large electrical box.

How relays work...
how relays work - Google Search

What I would do is install what is necessary to do the job right and up to code. If this means replacing the breaker panel, I would do that. If this means running new circuits and wiring, I would do that. If this means tearing out some drywall to run that wiring, I would do that too.
 
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Old 01-08-10, 05:53 PM
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Originally Posted by ray2047 View Post
Black and white can also be a 240v circuit. True in a perfect world the white would be remarked some other color but often it isn't. Not sure what a common neutral but the thermostat on a switched 240v circuit can be on only one leg so a continuous white which is not a neutral and a switched black is not uncommon on a 240v circuit.

Above assumes in location "Ca" is California not Canada.
Ray,

Yes, I'm in California, not Canada. Assuming this is a 120v circuit (which I can verify with a meter), can the thermostat be removed, the radiant heat conductors abandoned, and the existing wiring terminated with a standard outlet? If so, how should I proceed?

Thanks
 
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Old 01-08-10, 08:26 PM
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The key thing is that the gage wire will be large enough for the heaters you choose. I would suggest 240v heaters since you can get about twice the heat as 120v heaters on the same size wire. If the current heaters are 120v assuming space is available in the panel you should be able to change over to 240v. I would strongly suggest hard wired based on the number of melted plugs I've replaced on my own portable heaters. Have you considered baseboard heaters?
 
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Old 01-09-10, 09:38 AM
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Rick,

It is not that easy to decipher things that are posted here. Myself and others here try to error on the side of safety. It is hard to tell the background experience someone may or may not have based on the tone of the post.

True this is a DIY forum, but when you said you were going to make an assumption based on what seemed to be wire color alone it also set off a warning. To me that seemed like you might be creating a dangerous situation. I would have posted something very similar to Bill's post.
 
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Old 01-09-10, 09:16 PM
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I appreciate everyone's concern but keeping the thread on track... if the radiant heat is abandoned, what is the proper way to terminate two 10 ga Romex conductors and a ground wire into an outlet?

Although some have painted me as a totally inept individual, I'm far from that. I asked a legitimate question. I simply lack the formal understanding of the applicable codes. That's why we have forums, to educate people. Having a DIY forum where the canned response is "don't do it yourself" seems extremely counterproductive. I can appreciate professional electricians seeking out more work for their trade but this is the wrong place for that. Those replying here should appreciate that I want to do this correctly.

Interestingly, someone initially PM'd me stating he or she preferred that method of communication due to the propensity of these threads to go off-topic. I better understand his or her reasoning now.

I guess I'll just confirm it's 120v, add a 10 ga pigtail to the hot and neutral, install my outlet, and be on my way...unless someone has anything productive to add.
 
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Old 01-09-10, 09:42 PM
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We have some problems with your assumptions. Hard wired heaters are usually 240v but you are assuming 120v. Find the breaker is it 2 pole or single pole.

A #10 cable suggests a 30a breaker. Even if the circuit is 120v or rewired for a 120v a 30a breaker can not be used on a general purpose 120v circuit.

It sounds like you want to use 120v 1500 watt heaters as permanent heat source. They are not designed for that and because of their limited output won't give enough heat to heat a house.

What you should probably be considering is 240v baseboard heaters hard wired to the existing heat circuits.

To sum up you shouldn't use 120v portable heaters for what you intend to do. They are intended for 15 or 20 amp general purpose 120v circuits. They should not be use on 30 amp circuits which is what you probably have.
 
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