Conduit Repair

[Little Bill]

How would go about repairing this?
House is downhill from POCO underground service. The underground has pulled loose from the riser, shifted to the side, and is full of water.

Maybe the pictures will help my description some.

 

[petersonra]

UG conduits are often full of water. That does not bother me any. As long as the wires are not under any stress, I would not even attempt to repair the conduit. Maybe box in around it to try and protect the wires. If it moved once it will move again.

 

[mgookin]

I'd be most concerned about chafing on the conductor insulation. That looks like it's before the meter can. Doesn't poco maintain that? And I wonder if it's still moving.

 

[cowboyjwc]

As an inspector, I'd be more concerned about the fact the something (the house or the ground) has moved up or down 6" and over 2".

 

[ActionDave]

Expansion coupling to rejoin the pipe. If you want to go all out you could dig down to the ninety put a small hole in it and add some gravel under and around the pipe.

If it were my house I would do what petersonra suggested.

 

[Ponchik]

Would an expansion coupling prevented this?

 

[Little Bill]

I'd be most concerned about chafing on the conductor insulation. That looks like it's before the meter can. Doesn't poco maintain that? And I wonder if it's still moving.

I haven't contacted the POCO, but usually the customer is responsible for everything from the transformer to the house on an underground service.

I was also wondering/concerned about any stress this might have put the conductors under inside the meter can.

 

[growler]

I was also wondering/concerned about any stress this might have put the conductors under inside the meter can.

I think I would wonder about that to.


I would get the power company to kill the power and then check out the service cables. If the cable are good then I would rework the conduit and meter base as necessary to get it right.

If the homeowner wants a problem repaired I either repair it right or I don't touch it. If the owner want to put some sort of protection around those cables and hope for the best then that's his business.

 

[growler]

If it moved once it will move again.

Dirt can settle in a trench if it's not packed right to start with. The conduit was probably not at the very bottom of the trench and then dirt was just thrown on top. This would leave a void under the conduit and over time the pressure from the dirt on top would cause the conduit to seperate.

If you dig up the last few feet of trench and re-install the conduit and make sure there is dirt, sand or gravel under the conduit and then pack dirt around the conduit it should stay where it's put. The expansion coupling is a good idea.

 

[ActionDave]

Would an expansion coupling prevented this?

Probably if there were enough slack in the conductors.

 

[John120/240]

Expansion coupling to rejoin the pipe. If you want to go all out you could dig down to the ninety put a small hole in it and add some gravel under and around the pipe.

If it were my house I would do what petersonra suggested.

I'm with ActionDave. I have seen where the underground conductors exert enough force on the lugs to pull them loose from the meter.

 

[iwire]

The picture is why this code section exists.

300.5(J) Earth Movement. Where direct-buried conductors, raceways, or cables are subject to movement by settlement or frost, direct-buried conductors, raceways, or cables shall be arranged so as to prevent damage to the enclosed con-ductors or to equipment connected to the raceways.


FPN: This section recognizes ?S? loops in underground direct burial to raceway transitions, expansion fittings in raceway risers to fixed equipment, and, generally, the pro-vision of flexible connections to equipment subject to settlement or frost heaves.

 

[electrofelon]

The picture is why this code section exists.

A-men to that. I hate PVC so when I use it I am very meticulous: expansion couplings, clean joints, use a dauber that hasn't been dropped in the dirt, use primer, schedule 80 where it transitions from below to above grade, plenty of straps. Some of the stuff I have seen would give you nightmares!

 

[JDBrown]

This doesn't seem to be the case in this instance, but I've heard that problems similar to this can be caused by setting the conduit riser in the concrete slab rather than sleeving it. Can somebody elaborate on that for me? I'm having a hard time picturing it in my head. Thanks.

 

[cadpoint]

This doesn't seem to be the case in this instance, but I've heard that problems similar to this can be caused by setting the conduit riser in the concrete slab rather than sleeving it. Can somebody elaborate on that for me? I'm having a hard time picturing it in my head. Thanks.

Look up concrete curing, like here; weather, H2O and contant of the mixture all play a role.

Note the graphs on the lower part of the page.

Concrete is moving for a very long time, it is sweating or even absorbing the environment that it's in. They are stiil pumping water inside the pipes inside the Hoover dam to keep the curing concrete cool.

Concrete is like steel you can get all types.

 

[zbang]

They are stiil pumping water inside the pipes inside the Hoover dam to keep the curing concrete cool.

Sort of. The concrete was essentially cured within a year or so of building*; they did circulate chilled water to pull out the heat, and kept records of how much was removed. The water circulation was stopped in 1935 and the tubes then filled with grout. I've got all the info about that at home, somewhere.

*it will slowly continue to cure as long as the chemical reactions can keep going, but the main cure is long finished.

(IIRC, about half of the air compressors used were specifically built for conversion to ammonia compression when needed. Those formed the heart of the chiller system. see also http://www.usbr.gov/lc/hooverdam/History/essays/concrete.html)

 

[steve66]

If you fix the conduit, I would provide a small hole somewhere in the conduit to let the water drain out.

With a downhill run like that, the conduit call fill to the point where the water starts getting into the meter.

If the meter is really well sealed, it may even start filling up, or the water might follow the conduit into the house.

 

[kwired]

I was also wondering/concerned about any stress this might have put the conductors under inside the meter can.

A prescription of Xanax should take care of that:lol:

 

[Little Bill]

A prescription of Xanax should take care of that:lol:

Nah, no drugs. I've already scheduled a session with a "wirechologist"!