New 240V circuit - some specific questions

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  #1  
Old 08-11-04, 01:59 PM
ctann
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New 240V circuit - some specific questions

Hi there,

I am planning the install of a hot tub, and need to add a new 240V circuit.
(un?)luckily enough, my A/C fried a few weeks back, but with my new
windows, I find I don't really need it any more, so I am going to pull the
30A breaker in the box and add a 50A one for the new circuit.

The house is 35 years old, and the service panel is about 50' from where
the spa disconnect will be located. Existing circuits in the house (Al - yuck!)
just run the insulated wires up to the ceiling joists in the garage, and
along the (unfinished) beams, fastened by staples. They pass into the
ceiling of the house, and from there to wherever they are going. The
new disconnect panel will be mounted on an outside wall of the house.

So, my question is, do I need to run my new #6 CU 4 conductor cable
inside a conduit, or can I just add it in the same way as the rest of
the house cabling. I have no great objection to conduit, but can't make
the run with less than five 90 degree bends, and I believe the limit is
four. Plus, I'm kinda lazy, and just running wire would be less work!

So, assuming that I must use conduit, is that grey PVC stuff OK for in-house
work? I'm assuming I must use metal conduit for the last section to the
disconnect/GFCI box, and from there to the spa (it is mostly
under a redwood deck, except for the short drop from the box)

Thanks!

Chris ([email protected])
 
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  #2  
Old 08-11-04, 01:59 PM
ctann
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Oh, by the way, house is in San Jose, CA.
 
  #3  
Old 08-13-04, 11:44 AM
rlrct
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The rules for wiring in a spa are pretty specific. You might want to pickup/borrow a copy of the NEC and review Article 680 and the section on Spas and Hot Tubs.

Some general comments:
  • Wiring inside the house can be NM and transition to individual conductors when you convert to conduit for the outside runs. A conduit pull box is not listed for the connections, so you'll need an appropriate box for the switchover.
  • The disconnecting means for the spa must be within sight of the spa.
  • You need a 120v, GFI-protected convenience outlet between 5 and 10 feet from the spa.
  • The spa itself must be GFI-protected.
  • I don't remember anything in the NEC that required metal conduit. Your local AHJ may, but that seems a little unlikely.

Our install was indoors, and actually uses a maintained contact mushroom head pushbutton that controls a contactor as the disconnect. Looks a lot nicer than a big gray box on the wall in the room we built for the spa.
 
  #4  
Old 08-13-04, 12:03 PM
ctann
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Thanks for the reply. Any hints on where I might pick up the NEC
article? Is it online anywhere?

> Wiring inside the house can be NM and transition to individual conductors
> when you convert to conduit for the outside runs.

I will have the disconnect/GFCI mounted on an outside wall, so I should
then be able to run NW straight into the box and do the convert
to individual conductors there... Infact the box will replace an existing
110V outside junction box. So this sounds good, I can run regular
wire following the path of the existing wiring, and not have to do
any nasty #6 splicing... The box location will be about 12' from the
spa, and contain GFCI and disconnect.

> You need a 120v, GFI-protected convenience outlet between 5 and 10
> feet from the spa.

Are the measurements horizontal, or direct? There is an existing outlet
(plus the switch for the deck lighting) which is about 6' on a direct line
from the inside of where the tub will be, but I think its probably only
about 4 1/2' measured horizontally (i.e. its several feet above the height
of the tub). Rather than moving the existing
wiring, I may have to set the hot tub back from the deck a few feet
instead of right up against it if the measures are horizontal...

I also have existing spotlights, that are about 8' above the spa
and probably 4' away horizontally - I know the code mentions those, but
I have to go back and double-check. I can easily move those
though (and may well move them anyway).

Oh, another question. I saw a disconnect box advertised (specifcally
for spas), that contained a separate breaker for a 110V circuit,
and showed in the wiring diagram just one phase fromt the 220V
GFCI being pulled off to power it. But that would seem to me to break
code, right? A 220V circuit is supposed to be dedicated, and not used
to power any other equipment... Sounded like a nice idea when I
first saw it, but on thinking further, I think there are several problems
with it.

Regards,
Chris.
 
  #5  
Old 08-13-04, 12:58 PM
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Join Date: Sep 2000
Location: United States
Posts: 18,497
The NEC is available in the reference section of your public library. It is not online.

There is no blanket requirement for a 240-volt circuit to be dedicated. Besides, the line up to the spa disconnect box is not a branch circuit--it's a feeder.
 
  #6  
Old 08-13-04, 07:40 PM
rlrct
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Chris,

I misspoke about the requirement for the convenience receptacle between 5' and 10' from the inside of the spa. That's for an indoors installation.

An outdoors spa has to conform to the requirements for an outdoor pool except where overriden for hot tub/spa. In that case the receptacle must be at least 10' from the inside of the pool/spa [NEC 680.22(A)(2)].

I'd suggest spending the $40-50 to buy a copy of the NEC. Check on ebay - you can get a softcover version for under $30 if you don't mind waiting a week or 2 on the various auctions. Most libraries won't let you remove a reference book, at least in my area that's the way it works. Article 680 is the section on pools/spas. It's worth it to have the code - it has the answers to a lot of "what are the rules" questions once you figure out how to read it. I've also found dealing with the AHJ is much easier when I can ask intelligent questions about the code and how they interpret it.
 
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