Hi,

I am about to purchase and install this ceiling mounted electric heater:

Fahrenheat Ceiling-Mount Automatic 5000 Watt Electric Heater, Model# FUH5-4 | Heaters | Northern Tool + Equipment (http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_595_595)

It uses 240 Volts, 5000 Watts at 17,065 BTU/hr. It seems that it needs a 30 amp breaker and #10 wire. In my workshop I have a 30 amp circuit with #10 wire that was used to run a table saw. It is 220 power with a black wire a red wire and a white wire. No ground.

The breaker is a big fat one that says 30 amps with one switch to turn of and on. Am I set to install this heater?

Does this have anything to do with single pole or double pole breakers? I'm a little confused by exactly what that means.

Any advice would be appreciated... Thanks!

Five thousand (5000) watts is 41.66 amps, that's 20.83 amps on each leg of a 240 volt line. So you need 10/2 wire. The wire in your shop is 10/3. You need 2- wire cable not 3-wire, there is no neutral. Double pole breakers are like two breakers glued together. Some have two handles connected together, some only have one handle that trips both parts of the breaker. Double pole breakers connect to two places in the circuit panel, that's what gives you 240 volts.

hk:

You got the almost right answer, but for the wrong reasons.

P= V*I; so 5000/240 = 20.83 Amps. That current flows through each leg and it doesn't sum. It's just 20.83 Amps.

BUT...

Space heating is considered a continuous load so multiply by 1.25. Now we have like 26 Amps.

Upgrade to next breaker size and now we have 30 Amps and use #10.

Check those wires at the panel for your saw. Usually 240 will have two hots and a ground. The ground can be via conduit.

Yep, a little worried. 3 or 4 wires to the saw? Panel side?

Yep, my error.

Thanks for the replies.

I'm still not sure so I will be more specific. This is in a workshop. All of the wires are in conduit. Are you saying that conduit can act as the ground? I always wondered why there were no ground wires for any of the plugs etc.

If I only need 2 wires can I just cap of the white wire and not use it. I would have a red (hot) and a black (hot). I am trying to avoid opening the panel and messing around in there. I will go there if I have to but in this case it may not be necessary?

Once again I currently have a 30-amp breaker with #10 wires in conduit running to exactly where I want to put the heater.

1) Can I use the red and black wires on my heater and be OK?
2) What part does the white wire play? Can I just cap it?
3) Are you saying that conduit can act as the ground?

1) There is likely 240 there.
2) Neutral. If it's connected to a sub-panel, then it stays separate all the way back to the main panel (usually, rare exceptions). Cap, yes.
3) Yes, if metal.

Sounds good.

I will use a volt meter to confirm 240. Cap white wire.
There is no sub panel. The main panel is in the workshop with it's own utility meter. Conduit is metal...

Thanks!

Check from the hots to the conduit and hots to white wire and you should have 120.

I would pull a #10 ground, even if in metal conduit.