Non-metallic seal-tight

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goldstar

goldstar

Senior Member
Location
New Jersey
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Electrical Contractor
I'm figuring on a generator installation where 100' of conduit has to be buried along the side of a residence and there are at least five 90 degree bends. Running PVC and then trying to pull in the wire afterwards is out of the question. So, my thinking was to get a roll of 1 1/4" non-metallic seal-tight, roll it out on the lawn, pull in the wires I need and then lay it in the trench. My question is, is it permissible to bury non-metallic seal-tight in this situation ? The location is not one where the seal-tight has the possibility of being crushed.
 
356.10(4) For direct burial where listed and marked for the purpose.

356.26 Bends ? Number in One Run. There shall not be
more than the equivalent of four quarter bends (360 degrees
total) between pull points, for example, conduit bodies and
boxes.
 
The NEC requires the raceway be installed and complete before the conductors are installed.

Sounds like a hand hole is needed for a pull point.
 
goldstar said:
I'm figuring on a generator installation where 100' of conduit has to be buried along the side of a residence and there are at least five 90 degree bends. Running PVC and then trying to pull in the wire afterwards is out of the question. So, my thinking was to get a roll of 1 1/4" non-metallic seal-tight, roll it out on the lawn, pull in the wires I need and then lay it in the trench. My question is, is it permissible to bury non-metallic seal-tight in this situation ? The location is not one where the seal-tight has the possibility of being crushed.
Click to expand...

And, while I know that people often install that last couple feet in flex and ignore the 180 additional degrees of bend, there is nothing in the code that gives an exception for the number of bends in flex. So in other words, the 4-90's is applicable to flex right along with other conduit methods. If you really have a problem, you can buy MC rated for direct burial and solve it.
 
If given a choice as to the two methods which both violate the NEC I would choose running the PVC and pull with the 5-90's. As Bob mentioned you could always install a hand hole to be code compliant.
 
This is starting to look like a job that I want to walk away from. HO contacted me, he pulled all the permits, dug the 100' trench (which BTW is not 18" deep), poured his own pad, purchased the unit on line, etc., and is asking for a price to do the electrical work. The ideal spot would have been right next to his garage but he didn't want to locate it there. Says is looks ugly and it was right under his bedroom window. So, instead of running the electric 10' and the LP gas about 30' he's now faced with this 100' + situation. I took some photos with my I-phone - not the greatest but you'll get the idea. That's the LP gas line in the trench





 
If you're considering walking away, some would say "run!!!" I would say either run or ask to see the permit so you know he really has one, then price it at triple what you think you would normally charge. If you still get the job, triple should cover the stress and headaches.

I guess I'd tell him up front that He needs to remove that gas line because you need a deeper trench and don't want to be responsible for any damage while digging.
 
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If you run RMC you wouldn't have to dig the trench any deeper.

Looks like you burn four 90 deg bends just going around the stairs alone, making 45 deg bends instead of 90 to go around those steps is one possible way to help with number of bends.
 
kwired said:
Looks like you burn four 90 deg bends just going around the stairs alone, making 45 deg bends instead of 90 to go around those steps is one possible way to help with number of bends.
Click to expand...

I was thinking the same thing, have him re-dig the trench to get you at or under 360?.
 
Strathead said:
And, while I know that people often install that last couple feet in flex and ignore the 180 additional degrees of bend, there is nothing in the code that gives an exception for the number of bends in flex. So in other words, the 4-90's is applicable to flex right along with other conduit methods. If you really have a problem, you can buy MC rated for direct burial and solve it.
Click to expand...

What if you do the pull with the flex straight and then bend it to make the final connection/trench placement?
 
GoldDigger said:
What if you do the pull with the flex straight and then bend it to make the final connection/trench placement?
Click to expand...
That was my original thought and my reason for asking whether you can bury non-metallic flex but Iwire posted this and that kind of rained on my parade
iwire said:
The NEC requires the raceway be installed and complete before the conductors are installed.
Click to expand...
He didn't cite a code reference but I take him at his word
infinity said:
Would you really want to make the guy dig down 24" is that dirt?
Click to expand...
Some of it is soil but this is not the shore area. Every time you try to stick a shovel in the ground up here you hit a field stone.

But here's the "coup de grace". The guy called me today (I was just there to look at the job on saturday) anxious to get a price. I told him that the materials alone were in the $1200-$1500 area. I advised him that he had several Code violation issues including making the trench deeper. My labor would be in the $3500-$4000 area. He told me he got a price for $3000 to do the job complete. I guess I'm off the hook. Can't see how someone would do this job for $1500 in labor cost and take all that responsibility.
 
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