Critique my wiring plan (hot tub)

[soylentgreen]

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?

 

[jpimlott]

What is code for how far the disconnect from the spa?
Sounds good but not a sparky by trade.

 

[pvgirl]

To make the pull as easy as possibly you could pull the wire thru the conduit before installing the conduit on the building, also pulling lube can help with pulling the conductors. Things to note from NEC article 356, you must install it where not subject to physical damge so you may need to mount it high on the wall to keep it protected, also you can only have 360 degress of bends between pull boxes so depending on the route you take you may need to pull boxes. More practically installing and supporting the conduit so that it looks good, and doesn't sag may be the biggest challenge.

 

[soylentgreen]

Thanks! Some Updates:

• GFCI panel is just over 5 feet from tub and visible from tub, and no metal objects within that distance. I believe this meets code.
• I used a vacuum cleaner to pull a 100 foot nylon rope through the conduit after straightening it.
• I pulled the wires and almost made it, but after getting about 60 out of 80 feet the rope slipped off the wires. I had a helper for this, definitely a two person job.
• i cut the conduit about in half (40 feet), did the second pull, and added a waterproof junction box
• secured the liquid tight conduit to the side of the house using 1” EMT brackets and Tapcon concrete screws

so far it’s pretty clean and seems to be working ?