Electrical Conduit Crossing a Retaining Wall

Hi there,

I live in CA, building a 3' retaining wall in my yard and trying to plan the best way to pass electrical conduits through the retaining wall (imagine a 30' retaining wall and electrical conduit passing in the middle from one side to the other). The way I see it there are 3 options:

1. pass it under the retaining wall - is there a concern with settlement of the wall an cracking the conduit? do I pass them through the concrete footing (cement pour of a bout 1' foot) or even under the footing?

2. Pass it through the retaining wall, exit on the exposed side of the retaining wall into a junction box - are there any possible issues with water coming from behind the wall and corroding the box / bringing dirt on the exposed side of the retaining wall?

3. pass it above the retaining wall - to many exposed conduits and no wall the attach the junction box

Would appreciate if anyone has a suggestion or knows how to deal with such situation.

Also, does anyone knows the answer to the same question when trying to pass a water pvc instead of electrical conduit.

Thanks!

 

Can you go under the footing? Have you thought about running a sleeve through the wall and put your pipes through the sleeve? The sleeve would be over-sized and would allow for some movement.

There are PVC expansion fittings for the electrical conduit.

 

Is the best way to do a sleeve through the footing or go under the footing? I can do either...

 

I feel the sleeve would weaken the footing. I would go under it.

 

What if I go through the retaining wall - say in the middle, about 1.5' above ground and put a junction box on the other side of the wall (the exposed side)?

Seems that going under the footing will require lowering the conduit to more than 4' before getting to the retaining wall.

Would you be able to do the same for a pvc water line (i.e., going through the middle of the wall)?

 

Running the conduit (and water piping) under the footing is the proper way to do it. Running it through the wall will work but unless you have a need for the J-box (light or receptacle) it will look like crap.

 

Maybe I'm missing something. Have I got this right: You're running the conduit parallel to the face of the wall, for the full length of the wall, not perpendicular. So the power runs in one end of the wall and runs out the other end.

Why don't you run the conduit in the soil you are presumably "retaining"? The typical way is to bed the conduit in sand for a required or recommended diameter around the raceway. I used Schedule 80 PVC but I suppose rigid steel would be good, too.

I would do the same with your water line; Use NSF-rated 160 PSI polyethylene pipe which should be allowed under most codes.

For others following this thread, I am wondering if it's allowed to put everything in one sleeve, i.e. a 3" PVC pipe or conduit. For example, running plumbing, 120/240 VAC and low-voltage raceways all through the same sleeve.

 

I understood the line was perpendicular to the wall.