What Gauge Wire For An Electric Kiln?

[Isculpt]

I have a new electric kiln coming which needs to be wired.  I have a single phase home breaker box; the kiln requires a 70 amp breaker.  What gauge wire should be used by the electrician?  Friends, from a do-it-yourselfer to an electrical engineer, have insisted on everything from 4 gauge to 10 gauge. 

thanks, Jayne

[Pugaboo]

When I got my new kiln the book gave instructions as to wiring so you might call the manufacturer of the kiln and ask what they recommend. Or you might be able to find the manual online and download it and it should tell you as well. My Olympic 1823HE pulls a max of 30amps and is on a 40 amp dedicated breaker with #8 wire. The book said #10 or #8 so I went with the heavier wire just to try and make sure there was less stress on it. Also if the new wiring to the kiln has to run longer than 40 feet you have to step up to the next thicker wire. I am assuming with a 70amp breaker you will be direct wiring it so you won't need to know about plug configurations.

 

70 amps is pretty good size breaker make sure your panel can handle it as well since it needs to be on a circuit by itself. You dont want a fan or light somewhere kicking on and shutting down your kiln because that one small thing was just enough to push it over its comfort zone. I was also told to run the new line from the breaker to the kiln in a metal conduit on the surface of the wall so if ever there was an issue of the wires getting too hot I would be able to tell right away and not have wires overheating and melting inside the walls. I also had a special cutoff box installed with a switch that I throw whenever the kiln is not in use as an extra precaution.

 

I called and spoke with my insurance agent about insuring a kiln in the house and the only caveats he had was that it had to be installed by a professional licensed electrician to local code AND I could not hold classes on the premises where students would be firing their ware in it.

 

Once installed I ran my first test firing of the kiln and I stayed around to make sure all the conduit and electrical panels stayed cool just to be safe.

 

That's it that's pretty much everything I learned about getting a kiln installed properly.

 

Terry

[MichaelP]

Copper 4 AWG

[clayshapes]

Definitely ask the kiln manufacturer. Don't take chances with this. The manual that comes with the kiln should explain it properly - if not ask.

[Marcia Selsor]

The manufacturer should tell you or it will be in the manual.

 

Marcia

[Isculpt]

Thanks, all of you.  I didn't want to believe it was 4 gauge, but apparently it is!  Since it's such a large unwieldy gauge wire, I was going to run it up through the attic, then down again to a cut-off box by the kiln, but after Terry's comments, I think I may keep it in a conduit along the ceiling line. I need to have the wiring done before the kiln comes, so I'll double check with the Olympic folks, but it sounds like 4 gauge it is. 

[Wyndham]

You also need to know that your main service breaker box has enough total amperage for all your power needs in the building. In other words, if you have a 100 amp service(main breaker) and the kiln is drawing 70 amps, that only leaves 30 amps for the rest of the electric service for everything else, washer, dryer, fridge,hot water heater, ac, etc, otherwise you are overloading your main service.

You need to evaluate your total electrical  service and see how this added amperage fits in besides getting the correct wire gauge for the kiln.

Wyndham

[Diane Puckett]

Are you doing the wiring yourself or having an electrician do it? Having my studio wired was one time I was happy to pay for a licensed electrician and also permits which meant the work was inspected. Should there be a fire, I want everything to have be done by the book, even thou the studio is separate from the house.

 

I thought there was a recommendation of having the kiln as close as possible to the breaker box, but that may not be so.

[Pugaboo]

Diane,

You are right the closer to the breaker box the better. The further away from the box the bigger gauge the wire has to be or at least that is what I was told.

 

Terry

[atanzey]

Another part of the 'close to the electrical box' consideration is the cost of the wire.  Wait until you price that stuff out!

 

Alice

[Mark C.]

#4 is what you need for 70 Amps

If its a long run (means a very long way to box) you will need to upsize one gauge.

Your licensed electrician will cover all this.

Mark

[Isculpt]

Thanks all of you. No, I'm not doing the work myself.  But having spent years in the construction industry, one thing I learned is that it's helpful to know a little something about the work someone else will be doing.  You cannot imagine the non-code things I've seen licensed professional tradesmen do in new residential construction, which is where I spent much of my time between 2000 and 2008 (when the bubble burst).