pipe clearence under concrete

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beanman26

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Now here is the situation: Our secondaries were laid out months before I showed up and it ends up being that when coming out of the building the grade is the sidewalk adjacent to the building about 10 feet away. Now the area where our secondaries come out of the building are 1.5 inches below grade from top of the 4" pvc pipe........4" pvc the primaries are all set, they are 3 feet below grade already in the transformer pad.....Now the guy who did this told me there is no rule to this and that the 1.5"'s concrete poured over the pvc is good enough; he told me there is no rule. I looked at him kinda funny and said ok and came home and looked in 300.5 column 3 and 2nd row down it says ...."In trench below 50 mm (2in) thick concrete or equivalent which I think refers to without the concrete in that case it would have to be 12 inches correct me if I am wrong. In that same area this is where all our condensors will be laid on just outside the building. Now it won't be inspected when the concrete will be poured but I am just interested if this guy was thinking of something else or just covering his ass when I was just casually talking to him...it's not like I'm gonna throw him under the bus. Just any help would be great...beanman would appreciate it:grin:
 
I'm picturing the pipes coming down a good 30" or so out of the transformer pad, over towards the building, up to grade almost, into the building and then I guess at some point going back down so a 90 could be turned up into some gear or MDP. Is this right? Seems an odd (read: forced to as last resort) way to run conduit in a place where space will be tight.:-?

Careful beanman, you may be on a job from he** and your journeyman might be close to the edge.:D
 
Dave58er said:
I'm picturing the pipes coming down a good 30" or so out of the transformer pad, over towards the building, up to grade almost, into the building and then I guess at some point going back down so a 90 could be turned up into some gear or MDP. Is this right? Seems an odd (read: forced to as last resort) way to run conduit in a place where space will be tight.
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You're also picturing the interior floor at grade level.

I'd be concerned with conduit damage with a concrete sidewalk bearing directly on it.
 
LarryFine said:
You're also picturing the interior floor at grade level.
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Yes. The sidewalk is what makes me think so. I wondered if the interior floor would be higher but I personally don't see a lot of sidewalks on the outside so close and then the inside being raised. Of course it was a guess and I'm probably wrong as likely as I'm right.:smile:

As far as the pipes under the sidewalk, I figure the pipes turn down as soon as they get past the footing and by the time they hit the sidewalk they are low enough. I mean, they've got to go down to turn up into the transformer, right?
 
beanman26 said:
Now the guy who did this told me there is no rule to this and that the 1.5"'s concrete poured over the pvc is good enough; he told me there is no rule. I looked at him kinda funny and said ok and came home and looked in 300.5 column 3 and 2nd row down it says
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If these conduits contain service conductors that will end up under control of the utility the NEC does not apply to them.

Your 'service point' is likely to be the line lugs of the service gear, anything on the utility side of the service point is under utility control not NEC.
 
let me try to explain it a little better

let me try to explain it a little better

The grade from inside the building for the the secondary pipes are 18 inches higher than the actual grade from outside. I think there was no thought on the outside grade(I'm not sure because I was not doing the job at the time) but all I know is that the grade from where the secondaries are laid out is only at 1.5" below grade after coming through the granite cored holes to the outside with about a 6" strtaight stub sticking out for each parallel run. The transformer pad is 10 feet away from the outside stubs...the primaries were run another way to the transformer pad not sure why.....I am thinking by code just covering pvc under 1.5 inches of concrete is definitlely illegal by 300.5 but no inspector will be there to watch this go on....(plus there is only going to be grass to the transformer no sidewalks,driveways,parking lots ect.I am just wondering what will happen when the actual weight of all of the equipment being put outside will affect the pipes....I don't know, not sure..and plus gas lines are running right through our same area and we need 4' ( I believe thats only for the primaries though not sure) clearence this should be interesting but on the specs it was laid out exactly where it was suppose to be laid out. We are responsible for running the secondaries and primary pipes to the transformer pad...I am just curious why the primaries were done first and why not do the secondaries at the same time ...hmmm any more wisdom into regards of this situation...insomnia is keeping me up, I can hear my kid anticipating opening up his christmas presents since we are having christmas tommorrow..well have a great holiday guys :grin:
 
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I always struggle with the best answer and the accepable answer. Even if it were code compliant and you had no liability. What happens in years to come when the 1.5" of concrete cracks and needs to be replaced. Will someone be there to say "be carefull there are conduits in there" or will they jack hammer right into the conductors? Perhaps a concrete vault tight to the building where the stubs exit? This would allow for the runs to the xformer to stub up into the vault with 90's?
 
pipe clearence

pipe clearence

Jinglis you made a very good point and is kind of scary to think about....yeah Tuesday morning I'm gonna take care of it as best as I can. I will get to digging myself a trench and cut the secondaries as close to the building as possible with allowing a coupling to get on then 45 a few feet down then another 45 and stub up under the transformer pad george since it will only be a few inches of pvc covered in 1.5" ....but I am not sure if there are secondaries already out at the base of the transformer...they probably just need to be attatched, there must be stubs at the pad sticking out its aleady mounted but who knows I will find out tuesday....I'm pretty sure of it.....the good thing is there is only one 90 degree turn up to the wall so I will definitely have no need for a handhole enclosure because it will be at 270 defrees...it just worries me that little bit of secondary that will be only under 1.5" of concrete that worries me but I guess it will have to do.... I know nobody is gonna try and fix this one. well happy holidays time to travel over to the brothers house, our christmas is today...merrrrrry christmas :grin:
 
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Again I point out trying to apply 300.5 to this installation is very likely a mistake.

90.2 Scope.

(B) Not Covered. This Code does not cover the following:

(5) Installations under the exclusive control of an electric utility where such installations

a. Consist of service drops or service laterals, and associated metering,
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It is very likely this installation is covered by the NESC not the NEC.

That said I do not know the NESCs rules but the power company should be inspecting the work.
 
My point with the handwell at the point of entrance to the building was more to identify/protect the conductors. The handwell would be permanent at the surface and identify that some electrical is present. It also allows for the conduits to exit the bottom and eliminate any risk in the future.
 
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