Replies

1. 
   HammerHarry | Dec 15, 2004 08:06pm | #1

   Based on your question, I'd say what you need is an electrician.

   You'll need the proper sized cable from the panel to a disconnect mounted on the outside of the house where the heat pump will be located, and then appropriately sized and sheathed cable from the disconnect to the heat pump enclosure itself, plus you'll need appropriately sized cable from the panel to the air handling part of the system inside.

   Then you'll need the controls / thermostat cables. 

   Probably you could start by reading the manuals, but they probably won't be there until the heat pump is.

    

    

2. 
   BruceM16 | Dec 15, 2004 09:57pm | #2

   I'm doing the same.

   The electrician who helped me 'pull the wire' in wiring up my house, told me that I'd need to get UF 10/2 w/gnd back to an exterior disconnect box within a straight line of sight of the compressor. But I need to get back with him before I start trenching....shouldn't it be a 10/3 w/gnd if its 220? 

   BruceM

1. 
   DanH | Dec 16, 2004 12:04am | #4

   The outside unit doesn't generally need a neutral, so /2 cable is probably OK.

1. 
   BSayer | Dec 16, 2004 01:09am | #5

   Yeah, why doesn't an outside unit need a neutral? I noticed that was how my A/C was installed. I figured alternating current would always need a return path, but then again, I barely understand 120V stuff.

1. 
   KQRenovation | Dec 16, 2004 02:06am | #6

   I spoke with him again today and we got it straight.I need to run to a disconnect outside and a seperate line to the handler in the bsmnt, which will be right beside the panel.Thanks for all of your comments.

2. 
   DanH | Dec 16, 2004 03:00am | #7

   The two hot wires are "return" for each other.

1. 
   edwardh1 | Dec 16, 2004 03:06am | #8

   many heat pumps have a heat strip section for cold weather -
   those usually take bigger wire than #10 , probably 6 or 8 this is in addition to the 10 for the compressor that runs a say 3 or 3 1/2 ton unit.Mine has 10 gage - 2 hots and a ground .

2. 
   BSayer | Dec 21, 2004 09:48pm | #9

   So as one hot cycles "up" the other cycles "down"?Of course, I don't understand the concept of a neutral on alternating current....

3. 
   DanH | Dec 21, 2004 11:47pm | #10

   Yep, that's the idea. When one is all the way up and the other all the way down, the difference in voltage between them is 240V (well, actually more, but I don't want to have to explain the messy details).If you apply a 240V load across the two "hots" then no current flows in the neutral. And, if you put, say, one 100W bulb from one hot to neutral and an identical 100W bulb between the other hot and neutral, again, no current flows through the neutral.

2. 
   DaveRicheson | Dec 22, 2004 12:52am | #11

   If this is a new house, you may need to check your local electric code. The NEC also requires a 120v GFCI receptcal within 6' of an exterior unit. May as well put it in while you are pulling to the disconnect.

    

   Dave

3. 
   DanH | Dec 16, 2004 12:02am | #3

   You need to find out what the current draw of the unit is, and get appropriately sized wire and breaker. Make sure your panel has enough "juice" for the unit. (Should be at least a 150A panel & service for a heat pump, I'm guessing.) Generally an unfused disconnect is required outside near the unit, but this may vary by local code.

   Low-voltage wiring is also required, of course. This is basically thermostat wiring, but may require a cable with more than the standard 4 wires. Usually the unit will come with wiring instructions, but they may not be especially clear/detailed.

   A separate 24V transformer may be required, but usually the outside unit contains this.

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   Also, there are generally "emergency" resistance heaters in the air handler unit that need to be on separate breakers, with a separate feed from the panel.

   Edited 12/15/2004 4:04 pm ET by DanH

   
   

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   Edited 12/15/2004 4:05 pm ET by DanH