Repairing underwater connections.

[Fulthrotl]

I need to replace a 10 ft underground section of schedule 80 pvc going to a boat dock. When the water level is high enough you can dig a hole and it will fill up with water in this location. The repair must be able to survive this. What materials do you suggest I use to make the connections?

thanks

purple primer on the pipe and couplings.

and yes, the pipe will fill with water no matter what.
the primer lets the pipe weld togeather better so it
doesn't break again.

 

[markebenson]

purple primer on the pipe and couplings.

and yes, the pipe will fill with water no matter what.
the primer lets the pipe weld togeather better so it
doesn't break again.

.

Gotya on the primer. You know i visit a job i did 3 years ago with sch 40 on a rooftop. The pvc was strapped properly but it started zig zagging due to the extreme Florida heat and a coupler broke loose. Perhaps I should have used the primer there.

 

[ptonsparky]

You should have used a lot of expansion fittings and straps that allow the conduit to move. It probably would LLS anyway. That's a tough application for PVC if you want it to look pretty past installation.

 

[markebenson]

You should have used a lot of expansion fittings and straps that allow the conduit to move. It probably would LLS anyway. That's a tough application for PVC if you want it to look pretty past installation.

.
Thank you for the input. I have noticed some pvc jobs recently where the work has been coated with elastomeric sealer. I would be interested in the long term effect. I might do a test run next roof job.

 

[kwired]

I wouldn't use PVC on a rooftop if corrosive enough environment dictates maybe, PVC coated RMC. Maybe even stainless RMC?
Corrosive environment mostly to ferrous metals? - I'd still go with rigid aluminum before PVC on a rooftop.

FL rooftops probably see more extreme on the high end then here, but here there is possibly still a larger gap between the most extreme cold and most extreme heat and how much effect it will have on a PVC raceway on a roof then what is seen in FL. Better just build that rooftop PVC run out of expansion fittings with a little bit of raceway between them. We may see temp variance on a roof from low of -30F to a high of 150F.

 

[markebenson]

Did a repull yesterday. I know I made the right decision now. The run was about 100 ft 4 conductors 12 awg. $50 or so in wire, a couple hours in labor, Its a no brainer to me now. Never done a below sea level repair before.

Thank you everyone for the advice I really appreceate it!