Installing 4000 watt heater. I have a couple questions.

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Old 09-19-13, 11:00 AM
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Installing 4000 watt heater. I have a couple questions.

Hello.

Ok, im installing a 4000 watt electric heater. An in wall type. 240v. 16.7 amps.

Im planning on using existing wire that went to a now broken central air unit outside. That unit was on a 40amp breaker.

I understand that I must swap out that 40 amp breaker and put in a 30 amp double pole breaker for this device.

My question is, This heater calls for a 10awg wire to be used. Is it ok to use the existing wire that went to the ac unit? That wire is probably 8awg, i still have to check. Is it ok to use a larger than need wire for the run and attach the heater to it that calls for only 10awg? The heater would be the only thing on the circuit.

The heater has a black and white wire, with a ground screw on the casing. Pretty much standard like any other device ive seen. Anything different about 240v line I should be aware of? There are two hot wires at the breaker correct? I would just be swapping breakers and putting the wires back on the new one like they were on the old one. The other end of the line on the AC unit has a black, white and ground wire. So should be straight forward to hook up.
 
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Old 09-19-13, 11:33 AM
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Welcome to the forums!

I understand that I must swap out that 40 amp breaker and put in a 30 amp double pole breaker for this device.

My question is, This heater calls for a 10awg wire to be used. Is it ok to use the existing wire that went to the ac unit? That wire is probably 8awg,
Yes. So long as all of the strands in the existing conductors will fit into the lugs on the new breaker and on the heater, the larger size of the wires is not a problem.
 
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Old 09-20-13, 01:54 PM
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Ok I have another question.

The cable thats already ran to the old ac unit, i looked at it today. It appears to be 8awg stranded outdoor cable. Its mostly buried under the ground under my mobile home.

However, this cable is not long enough to reach where I need it to get to this heater. It is probably 20 feet short id guess.

Are you able to couple another wire onto this existing wire safely? Solid outdoor 8/2 wire here is $1.93 a foot so it would save me a bunch of money if this is possible. Didnt know if this could be done on that thick of wire on a 240v 30 amp circuit.

If it can be done what is the best way to do it? Regular twist on couplers or is there something better and safer? Thanks.
 
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Old 09-20-13, 07:00 PM
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Are you able to couple another wire onto this existing wire safely?
Depending on the location, the existing cable can be spliced in a proper junction box. Since this will become a 30A circuit, you'll only need to use #10 cable. If this is outside (it sounds like it is outside), you'll need to use 10-2 UF cable. The junction box outside will also have to be weatherproof. Yes, there are wire nuts to splice a #8 to a #10.
 
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