Wiring 220 for a new Hot Tub

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Old 08-26-09, 10:27 PM
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Wiring 220 for a new Hot Tub

I have a new 48A Hot Tub that calls for DEDICATED 220 with a 60 amp GFCI Breaker and 3-Wire. I would like to wire it with 4 wire and run the wire in the crawl space under the house (dirt surface). I plan to use 6 AWG and it will run about 130' from the main Breaker to the Hot Tub.

Wiring:
How do I wire 4 wire even though the wiring diagrams for the Hot Tub call for 3 wire? Where should I connect the extra wire?

Conduit:
What conduit is best to use under the house along the dirt? Does the conduit need to be attached to the joists beneath the house, or can it sit loose atop the soil in the crawl space? The crawl space is only 18" high for about 100', so the less work securing the conduit, the better.

I would like to set up an additonal circuit while I am pulling this wire. Is there a legal limit to the numbers of wire I can pull through a conduit?

Switch/Shut-off:
The manual also calls for a switch that is "easily accessible to the Spa occupant, but at least 5' from the Spa". I read somewhere else this distance needs to be at least 10'; which is correct per code (NEC and/or California)? What equipment would be best to use for this switch? If I already have a GFCI at the main, do I need anything special as far as this switch goes?

Thanks in advance for the advice!
 
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Old 08-26-09, 10:53 PM
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Wiring:
How do I wire 4 wire even though the wiring diagrams for the Hot Tub call for 3 wire? Where should I connect the extra wire
The fourth wire is the ground wire. It must be insulated and colored green. It can be #10. The wires must be THWN. Depending on the actual amperage requirements of the hot tub because of the distance you may need to use two #4 black and one #6 white.
Conduit:
What conduit is best to use under the house along the dirt? Does the conduit need to be attached to the joists beneath the house, or can it sit loose atop the soil in the crawl space? The crawl space is only 18" high for about 100', so the less work securing the conduit, the better.
You can bury it 18" or secure it to the bottom of the joists. 1" PVC conduit should be OK.
I would like to set up an additional circuit while I am pulling this wire. Is there a legal limit to the numbers of wire I can pull through a conduit?
Will it be a 120v 20a circuit?
Switch/Shut-off:
The manual also calls for a switch that is "easily accessible to the Spa occupant, but at least 5' from the Spa". I read somewhere else this distance needs to be at least 10'; which is correct per code (NEC and/or California)? What equipment would be best to use for this switch? If I already have a GFCI at the main, do I need anything special as far as this switch goes?
A 60a unfused air condition disconnect should be OK. I will let the pros say what distance.
 
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Old 08-27-09, 05:10 AM
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Check your instructions for clarification on whether your tub needs a neutral. I suspect the green grounding conductor is needed, but not the neutral. Details, details.

There are also bonding issues with hot tubs and the need for a 120 volt GFI receptacle near the tub. Are you taking care of these issues also?
 
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Old 08-27-09, 08:20 AM
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Originally Posted by Blue Lt Special View Post
How do I wire 4 wire even though the wiring diagrams for the Hot Tub call for 3 wire? Where should I connect the extra wire?
What wires are actually called for? Sometimes when they say "three wire" they mean four wires because the ground is implied. See if the tub requires a neutral.

What conduit is best to use under the house along the dirt? Does the conduit need to be attached to the joists beneath the house, or can it sit loose atop the soil in the crawl space?
1" or 1-1/4" PVC will be best. It needs to be fastened to the joists every 3' (every other joist). Flexible ENT conduit would probably be ideal, but in that size it is a special order in many areas -- still has to be fastened every 3', but it comes in a 100' roll so no gluing in cramped spaces. You could use metal conduit like EMT which only needs to be fastened every 10', but it's heavier and clumsy to work with in confined space.

I would like to set up an additonal circuit while I am pulling this wire. Is there a legal limit to the numbers of wire I can pull through a conduit?
Yes. If you're talking about the required 20A circuit near the tub, then 1" conduit will be sufficient for 2 #12, 1 #10, 3 #6. Please us know if you had something else in mind.

The manual also calls for a switch that is "easily accessible to the Spa occupant, but at least 5' from the Spa". I read somewhere else this distance needs to be at least 10'; which is correct per code (NEC and/or California)?
The NEC requires that the disconnect be on the same grade as the spa, within line-of-sight and no closer than 5' from the rim of the spa. Some local codes also add a maximum distance.

The 10' rule you're thinking of is that no electrical outlet may be within 10' of the rim of the tub.

The general purpose receptacle must be greater than 10' but less than 25' (I think -- I'll look it up if you're close to the limit) from the tub.

What equipment would be best to use for this switch? If I already have a GFCI at the main, do I need anything special as far as this switch goes?
If you used a GFCI breaker, a simple 60A non-fused pull-out would be fine. If you don't use a GFCI breaker, a spa disconnect panel with built-in GFCI is ideal.
 
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Old 08-29-09, 12:27 PM
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Thanks a bunch for all the help. Another question just came up; not sure if this is the right forum:
I need to pour a 4" reinforced concrete pad below the hot tub. I read somewhere that I might have to ground the rebar back to the electrical service panel. Is that true?
 
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Old 08-30-09, 07:07 AM
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I does not need to be grounded back to the panel. You will need to BOND the rebar with a piece of #8 solid copper to the lug on the wiring compartment and/or motor. There are clamps made to connect to the rebar.
 
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Old 08-31-09, 09:49 AM
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Originally Posted by Blue Lt Special View Post
I read somewhere that I might have to ground the rebar back to the electrical service panel. Is that true?
It is true that you need to bond it to the tub. If you are not running the conduit through the pad, the best way is to leave a piece of copper, brass or stainless #4 (1/2") bar poking a few inches out of the side of the pad near where your electrical will come in. Make sure to tie it to the bar or mesh in the pad with rebar tie wire. Don't leave plain iron bar poking out though the rust will make the connection worthless and will eat into your concrete.

If you are running conduit through the pad, clamp the solid #8 copper wire to the rebar with a brass clamp before you pour concrete and leave several feet of wire poking out right next to the conduit so when you set the tub on top, the bonding wire goes right into the spa wiring compartment with the supply conduit.
 
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Old 08-31-09, 10:04 PM
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Should the solid #8 copper wire be THHN?
 
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Old 09-01-09, 05:36 AM
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The bond wire can be cover or bare. I would use the green insulated. Makes its purpose known.
 
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