Outdoor hot tub wiring question p here

[jsalbre]

I could use some help here.

I’m in the process of wiring up for a hot tub (work will be inspected prior to “go live”), and I’m struggling to come up with the best method. Tub requires 4 wire 240v. I have a sub-panel with available capacity in an outbuilding near where the tub will be placed, so I don’t have to come from the main house panel. Dropping a 50A GFCI in the panel, running 6/3 NM-B from the sub panel through the building walls to the disconnect panel on the exterior wall, transitioning to 6awg THWN in PVC conduit from there, ending in a 6’ watertight nonmetallic flex conduit near where the wiring goes into the tub shell.

My question revolves around the rigid PVC in the middle. I’d like to avoid burying if possible, as the ground is pretty rocky and will take an excessive amount of work to get 18” deep. From my understanding even though the PVC can be above ground it cannot be at ground level. However, the outbuilding and tub sit on ground supported by a retaining wall built from railroad ties. Both are only a couple feet from the edge of this wall. Can my PVC run over the edge of the wall from the outbuilding and then along the outside of it to where it needs to come back up for the tub feed?

if not, are there any better suggestions vs burying?

Thanks.

 

[growler]

My question revolves around the rigid PVC in the middle. I’d like to avoid burying if possible, as the ground is pretty rocky and will take an excessive amount of work to get 18” deep. From my understanding even though the PVC can be above ground it cannot be at ground level. However, the outbuilding and tub sit on ground supported by a retaining wall built from railroad ties. Both are only a couple feet from the edge of this wall. Can my PVC run over the edge of the wall from the outbuilding and then along the outside of it to where it needs to come back up for the tub feed?

if not, are there any better suggestions vs burying?

Thanks.

You can strap PVC to a cross tie wall if that's what you are asking.

If you do need to bury the conduit and have trouble with the 18" for PVC then you may want to go with rigid metal conduit and only go 6".

 

[Dennis Alwon]

IMO, schedule 80 PVC can be laid on the ground with proper supports however I would not want to do that.

If I understand your question then I don't see any problem running pvc along the outside of a building. Some inspectors may want schedule 80 where the conduit may be subject to physical damage.

 

[jsalbre]

I’m not sure I described the situation well enough to be clear. I took and marked up a couple quick photos to help illustrate what I’m talking about.

In the first photo P is the subpanel on the inside of the building, dashed blue line would be the NM-B in the wall. Green D is where the disconnect panel will go.

The second photo is from the other side of the retaining wall looking back at the building.

The question is can I run the conduit over the side of that wall and along the outside? Or even if I use rigid metal go along the inside edge of that retaining wall?

Thanks again.

 

[jsalbre]

Forgot the pictures!

I’m not sure I described the situation well enough to be clear. I took and marked up a couple quick photos to help illustrate what I’m talking about.

In the first photo P is the subpanel on the inside of the building, dashed blue line would be the NM-B in the wall. Green D is where the disconnect panel will go.

The second photo is from the other side of the retaining wall looking back at the building.

The question is can I run the conduit over the side of that wall and along the outside? Or even if I use rigid metal go along the inside edge of that retaining wall?

Thanks again.

 

[Dennis Alwon]

Yeah you can do that. It is certainly the long way to go but it looks good to me

 

[jsalbre]

Yeah you can do that. It is certainly the long way to go but it looks good to me

Thanks. It’s definitely a further run around the side like that, but it saves me the time and expense of trenching, and keeps it out of view, which makes the wife happier.

One additional question a neighbor brought up, what about running on top of that wall, or would that still be considered “ground level”?

 

[PaulMmn]

Looking at your pictures, the area surrounded by the RR Ties looks like it's a lot of fill. Is the fill that rocky??

 

[jsalbre]

Looking at your pictures, the area surrounded by the RR Ties looks like it's a lot of fill. Is the fill that rocky??

Surprisingly yes. The fill is basically what they dug out for the partially exposed basement of the house. It’s on a mountain made of mostly granite, so there’s large chunks. It makes had digging a pain, and I’m concerned about the potential damage to a powered trencher.

 

[Jon456]

and keeps it out of view, which makes the wife happier.

Burying it would also keep it out of view. Unless you & your wife spend a lot of time underground.

Frankly, trenching and burying it would be the better way to go. If the retaining wall starts to bow out over the years, you'll have problems. Plus you'll probably see some of the conduit where it goes over the wall (twice) and it will be ugly. The distance doesn't look that far. Hire one or two guys to help dig it out. The cost will be partially offset by the savings on fittings, clamps, and wire.

 

[jsalbre]

Burying it would also keep it out of view. Unless you & your wife spend a lot of time underground.

Frankly, trenching and burying it would be the better way to go. If the retaining wall starts to bow out over the years, you'll have problems. Plus you'll probably see some of the conduit where it goes over the wall (twice) and it will be ugly. The distance doesn't look that far. Hire one or two guys to help dig it out. The cost will be partially offset by the savings on fittings, clamps, and wire.

Man, stop making so much sense!

You're right of course, that’s really what I should do. I had some other big reason why I didn’t want to go underground at first, but now I can’t for the life of me figure out what it was, so underground it is. Thanks for talking some sense into me.

i appreciate all the input folks.