soylentgreen
New Member
- Joined
- Apr 23, 2021
- Messages
- 90
My plan to wire up a hot tub for 240VAC. (USA). Hot tub is located about 80' from the main panel (house has normal USA 100A service). My tub only requires a 30A service on the label, and actualy would run about 20A, so I decided that 8 gauge was enough, giving a 2% or less voltage loss.
The house is on a slab, so no way to go through the house. The shortest run is along the outside of the house. Unfortuantely, there is no straight shot: about every 10 feet there is an obstacle to dodge (gutters, fence, other wiring races, plumbing, etc.).
I had thought about doing this with THHN inside EMT, but feared with these obstacles, I'd be doing complex EMT bends more often than not.
I researched armored metallic cable, but it seems that almost nobody makes 8 gauge armored cable, and when they do, the ground wire is bare, which I understand violates the NEC for spa installation. And it's as expensive as THHN.
I looked into direct burial wire, but same issue: the ground wire is bare, and it's no cheaper than 4x THHN. Also, at my house, there's not really a way to bury it without even more trouble.
So I came up wit this plan:
- THHN 8 gauge stranded x 4 (red, black, white green)
- run wires inside of liquidtight non-metallic 3/4" conduit (about 80')
- wires terminate at standard GFCI spa disconnect panel
- from GFCI panel, continue wires inside liquidTight to spa (about 15')
It wasn't immediatlely clear to me if long runs of liquidiTight are legal, but my conclusion was that yes, they are legal (as long as supported properly) but just that it's hard to do wire pulls through long sections. If I have trouble with a single 80' pull, I can easily break it up into two 40' pulls with a waterproof Junction box.
How does this sound?
The house is on a slab, so no way to go through the house. The shortest run is along the outside of the house. Unfortuantely, there is no straight shot: about every 10 feet there is an obstacle to dodge (gutters, fence, other wiring races, plumbing, etc.).
I had thought about doing this with THHN inside EMT, but feared with these obstacles, I'd be doing complex EMT bends more often than not.
I researched armored metallic cable, but it seems that almost nobody makes 8 gauge armored cable, and when they do, the ground wire is bare, which I understand violates the NEC for spa installation. And it's as expensive as THHN.
I looked into direct burial wire, but same issue: the ground wire is bare, and it's no cheaper than 4x THHN. Also, at my house, there's not really a way to bury it without even more trouble.
So I came up wit this plan:
- THHN 8 gauge stranded x 4 (red, black, white green)
- run wires inside of liquidtight non-metallic 3/4" conduit (about 80')
- wires terminate at standard GFCI spa disconnect panel
- from GFCI panel, continue wires inside liquidTight to spa (about 15')
It wasn't immediatlely clear to me if long runs of liquidiTight are legal, but my conclusion was that yes, they are legal (as long as supported properly) but just that it's hard to do wire pulls through long sections. If I have trouble with a single 80' pull, I can easily break it up into two 40' pulls with a waterproof Junction box.
How does this sound?