I am installing an older Sonoma Spa self -contained Hot Tub. It is a Handyman Special.It has to be hardwired 220. I have done all the fixing up to this point and am ready to run the electrical. Just a couple of questions.

1) Does the GFCI (50 Amp Double Pole) have to be in the disconnect box or can it be in the service panel?

2)The service panel is about 25 feet from the tub. (outside installation) What type of conduit should I use. I have not decided if I will bury or leave the install exposed.If it is left exposed it will run along the slab foundation of the house. An answer for both would be great. I have already purchased the wire. (6/3 Romex w/10 gauge ground rated at 55 Amps 600 volts)

Thank you in advance,

David Hagar

 

David,

You should check with your local AHJ to see if they have specific requirements for your area. A couple of things, though:

Unless your area has specific requriements, there isn't anything in either the 99 or 02 NEC that forces you either way - just that you have GFCI protection for the spa.

If you bury the conduit, it needs to meet the requirements based on the type of conduit you're running. For example, rigid metal conduit or intermediate metal conduit only needs to be 6" down but non-metallic conduit has to be 18" down. You could also use direct-burial rated MC cable, but it has to be 24" down.

You can run up to 6' of liquidtight flexible metal conduit or liquidtight flexible nonmetallic conduit. You can also use a cord-and-plug connection with up to 15' of cord.

Nonmetallic conduit is probably the easiest to work with if it's not in an area subject to damage (ex. lawnmowers bumping into it and cracking the conduit). I'd run it along the foundation rather than having to dig. The rules about supporting conduit also vary by type.

It's my understanding that NM isn't rated for wet location and outdoors as you're doing is wet location. The best thing is probably to pull THWN.

Rob

 

Thank you for the response. I have gone ahead and dug a trench and will be using 1" SCH 40 PVC. There is a conflict though.I had read in other places I could pull Romex as long as it was conduit. Do you think this would be ok or should I really use THWN? Will I end up with that many problems using Romex? Thank you again!!!

 

You should not use Romex in conduit in general (except for a short distance when the conduit is for protection only).

For a hot tub you may never use Romex outdoors. Hot tubs and swimming pools require that you use individual shielded conductors for all the wires, including the ground when outdoors.

 

As has already been stated, hot tub wiring is a very, very specialized area. Almost everything you know about the rules for ordinary circuits don't apply here. There is a completely new set of rules. I suggest you visit your public library and read article 680 of the NEC.

 

Thank you all for the advice. I realize that this is a specialty wiring situation and have read article 680 now. From all the research I have done I think I am ready to proceed. I did exchange the 6/3 romex nm for thhn. Thank you all again.

 

I hope you meant that you got THWN - THHN isn't rated for wet locations and underground is a "wet" location.

 

Most THHN is dual rated THWN, but make sure yours is. And be sure to use an insulated grounding wire (another reason not to use 6/3 cable).

 

Can you run 6/3 Romex from the service panel in the house to the GFCI disconnect which would be on the outside wall of the house and then run THHN wire from the disconnect to the tub?

 

Yes, but only if there is no overcurrent protection at the disconnect and only if this is a one-family dwelling.