50A Hot Tub electrical connection questions

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  #1  
Old 06-15-07, 08:18 AM
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Question 50A Hot Tub electrical connection questions

I am installing a hot-tub that requires a 50A/240V electrical supply, and would appreciate any help understanding exactly what needs to be done.

The hot-tub is being installed on a deck that requires almost 100' of wire to reach the service panel. Of this distance, approximately 75' is within the basement, the other 25' is outside, under the deck. The plan I have is as follows:

1. Install a 50A/250V non-GFCI CB (e.g., Westinghouse BR250) in the service panel.
2. Run ~85' of 6/3 wg wire from service panel to Hot Tub Disconnect Panel (e.g., Siemens 50A GFCI Load Center). 10' of this run is under deck, remainder is in basement. I intend to connect the disconnect panel as shown in http://www.hawkeyespas.com/images/pdfs/WiringDiagramSiemens.pdf
3. Run ~15' of 6/3 wg wire from Hot Tub Disconnect panel to Hot Tub Control System unit.

So the questions I have are:
Q1: I assume I only need GFCI in the disconnect panel and not in my service panel, is that correct?
Q2: What type of wire and conduit do I need to use for each leg? Can I use NM-B in a plastic conduit? Or do I use UF (with conduit)? Do I need to use the conduit in the basement or just on the exposed portions of runs? Do I need to run separate ground wire or is the bare "wg" wire sufficient?
Q3: There is a metal downspout within 5' of hot tub - should this be grounded(via separate wire) to the grounding block of the disconnect panel?

Thanks for any help.
-PG
 
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Old 06-15-07, 08:34 AM
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1) You do not need a GFCI in the main panel since there is one at the disconnect.

2) You can use NM-B cable inside, but outside you must use individual wires inside conduit and the ground wire must be insulated. This generally means THWN wire.

3) The proper term would be bonded, not grounded. I would ask the inspector. Mine explicitly did not want my downspout bonded.

Don't forget that you need a convenience receptacle nearby. You may be able to install a breaker for one in the disconnect. If not, you will need to wire one.
 
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Old 06-15-07, 09:09 AM
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> What type of wire and conduit do I need to use for each leg?

At least 1" PVC from the house to the disconnect and from the disconnect down under the deck. The last 5' or 6' of conduit should transition with a pull box or threaded adapter from PVC to liquidtight flex conduit for the final connection to the tub.

> Can I use NM-B in a plastic conduit?

Only from the exit of the house to the disconnect.

> Do I need to run separate ground wire or is the bare "wg" wire sufficient?

Up to the disconnect, the bare ground is okay. From the disconnect to the tub you must have a green insulated ground.

> Run ~15' of 6/3 wg wire from Hot Tub Disconnect panel to Hot
> Tub Control System unit.

This has to be insulated THWN wires in conduit.
 
  #4  
Old 06-16-07, 06:28 AM
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Thanks for your helpful responses!
 
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