New circuit for heat pump

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Old 07-09-08, 11:31 AM
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New circuit for heat pump

Getting ready to have a 3 ton heat pump installed, and I need to run a new circuit for the compressor. Compressor MCA is 18.7 and max overcurrent device is 30A.

The circuit will run from a 100A sub-panel in an unconditioned utility room, down through the floor into the crawlspace, and across the crawlspace to the exterior wall. Total run length is about 50 feet. Compressor disconnect will be mounted on the outside of the crawlspace wall. The crawlspace is pretty tall, so I can mount the disconnect > 24" above grade no problem.

Can I use 10/2 MC cable for the entire run?

Can I run the MC cable through the exterior wall and straight into the back of the disconnect? Or do I need to transition to something else before going through the wall?

Thanks.
 
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Old 07-09-08, 11:55 AM
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Originally Posted by jcm55 View Post
Can I use 10/2 MC cable for the entire run?

Can I run the MC cable through the exterior wall and straight into the back of the disconnect?
Yes to both questions.

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Old 07-09-08, 09:31 PM
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Oui { Yes }.,,
It will work fine with the question you asked here but however there a little tibbite I will add along the way Per NEC code requriement,.

If you have a 120 v outdoor receptale withen 25 feet of the outdoor compressor unit that will be fine otherwise it will be wise idea to add one near the outdoor compressor { just keep in your mind all the outdoor receptales have to be GFCI but do not tapped from Kitchen circuits ditto with bathroom or landury room circuits }

Merci,Marc
 
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Old 07-10-08, 07:31 PM
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Originally Posted by jcm55 View Post
Can I use 10/2 MC cable for the entire run?
Unless there's some local code forbidding it, you can also use NM-B (Romex) since it won't be exposed outside. [Much cheaper than MC/AC]
 
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Old 07-10-08, 09:15 PM
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You could also use # 12 AWG if you wanted to save some money.
 
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Old 07-11-08, 08:14 AM
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Stick with the MC if you have any rodent activity in your crawlspace -- they love to chew up NM cable.
 
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Old 07-11-08, 09:31 AM
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Originally Posted by ibpooks View Post
Stick with the MC if you have any rodent activity in your crawlspace -- they love to chew up NM cable.
Ahh, good call. Thanks!

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