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Wiring to spa disconnect panel - NM or individual conductor?

Wiring to spa disconnect panel - NM or individual conductor?


Old 08-30-04, 05:56 PM
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Wiring to spa disconnect panel - NM or individual conductor?

Hi all,

I know there are a bunch of 220V questions on here.
As recommended, I went out and bought the NEC2002. It is kind of scary
when you talk to people at Home Depot, who obviously have no idea
on code - I'm glad I am doing my own research!

So, I just wanted to check my assumptions. I am running about 100' from
my main service panel to my new spa disconnect/GFCI box. The box will
be attached to the house, and so all wiring _to_ the box will be "inside".
I know that for the wiring run from the box to the spa, I will be using
4 #6 THHN conductors inside a conduit.

My question is, can I use NM cable for the run from my main service to the
box? The only #6 NM I could find was 6/3, which had a "covered" ground
(i.e. not insulated, but wrapped in cardboard), that was significantly smaller
than #6 (not sure if it was #8 or #10). If I understand right, I should
have the same size ground (although covered may be alright - the
"insulated requirement" is for the outside part, right?).

So, is this 6/3 NM going to work for me, or am I going to have to pull
4 individual conductors?

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Old 08-30-04, 06:37 PM
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1. I don't see any reason you couldn't use NM cable for your interior cable run.
2. Use Table 250.122 of the 2002 NEC to determine the minimum allowable size for the grounding conductor. It does not always need to be as large as the current carrying conductors. For instance, you can use up to 60 amps with a 10 AWG equipment grounding connector.
3. You would probably need to use THWN in buried conduit outside, as it is considered a wet location.
Old 08-30-04, 07:11 PM
Join Date: Aug 2004
Location: Toronto, Ontario
Posts: 91
As sjr states there is no problem using NM inside to box on wall then NM-W in conduit from breaker box on wall to control box on the spa. As for using 6/3 you will have to go to the manufacturer to see what the current load is for the tub. For a distance of 100 feet you may or may not have to drop down a size in wire.
Old 08-31-04, 12:01 PM
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Join Date: Jul 2002
Location: Maryland
Posts: 14,433
I am not quite sure what NM-W type wire is. If Exile means type UF cable to be used outside this would NOT be compliant as the ground is covered, not insulated. Once the wiring method breaks the outer plane of the house it needs a insulated ground.
Old 08-31-04, 12:54 PM
Join Date: Sep 2002
Location: welland ontario
Posts: 5,599
NM-W is the Canadian version of Non Metalic Wet. Used in wet locations. I think it is equal to UF cable.

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