Gas Dispensing

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augie47

augie47

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State Electrical Inspector (Retired)
Art 500s remain a weak link in my chain. Typical gasoline service station. Rigid conduit stubbed up at pumps with a sealoff as the 1st fitting.. continues 20ft deep due to a vehicular traffic area. At the edge of the traffic area, some 15 ft from the dispenser, offsets are bent to allow the rigid to run under a sidewalk to the building where they run just below the building slab until they turn up to another sealoff. Compliant ? (No PVC involved).
(I see Exception 2 to 501.15(A)(4) and question the conduit being in the gravel under the building slab. )
 
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I've mentioned before that a problem with Article 514 is that it is basically controlled by a different Technical Committee than CMP 14. By most common area classification practices the underground would be unclassified; but Article 514 treats it as a classified location because of potential spillage.

If the partial run in question was outside of the 20 foot "spill zone", I wouldn't be concerned at all. Personally, I would still be inclined to accept it as described; especially if it is entirely in RMC and sealed at both ends.
 
I've seen it done that way all the time. I've even seen someone use PVC under the building at less than 24" of cover (turning up in rigid) which I believe is not in accordance with the NEC.

I'm confused as to where your concern is. Being under the building and traffic area (sidewalk), the 24" requirement is no longer viable (since PVC is not used). Something has you questioning this and I'm not sure what it is.
 
oldsparky52 said:
I've seen it done that way all the time. I've even seen someone use PVC under the building at less than 24" of cover (turning up in rigid) which I believe is not in accordance with the NEC.

I'm confused as to where your concern is. Being under the building and traffic area (sidewalk), the 24" requirement is no longer viable (since PVC is not used). Something has you questioning this and I'm not sure what it is.
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300.5 would require the traffic area to be minimum 24" deep no matter what the wiring method is, and is also independent of hazardous location articles.
 
kwired said:
300.5 would require the traffic area to be minimum 24" deep no matter what the wiring method is, and is also independent of hazardous location articles.
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I thought we all knew that, so I'm confused by your post.

Edit: I see, in the post you were responding to I mentioned traffic area the sidewalk in parenthesis, what I meant was out of the traffic area under the sidewalk.
 
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My concern is the wording in 501/15 (A)(4) Excption2 which allows the Rigid conduit to be run
beyond the boundry to the point where it emerges from below grade to a sealoff.
If the conduit is routed under the building slab (on top of or barely set in the gravel under the slab) is this still considered "below grade" until it actually turns up thru the slab to the sealoff.
 
augie47 said:
My concern is the wording in 501/15 (A)(4) Excption2 which allows the Rigid conduit to be run
beyond the boundry to the point where it emerges from below grade to a sealoff.
If the conduit is routed under the building slab (on top of or barely set in the gravel under the slab) is this still considered "below grade" until it actually turns up thru the slab to the sealoff.
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It's fine. There's no other practical location for the seal to be accessible. See Section 501.15(C)(1).
 
oldsparky52 said:
I thought we all knew that, so I'm confused by your post.

Edit: I see, in the post you were responding to I mentioned traffic area the sidewalk in parenthesis, what I meant was out of the traffic area under the sidewalk.
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I now see that I likely misunderstood what you were trying to say, I was just pointing out that under the vehicular traffic area and regardless of the wiring method it must be at least 24 inches deep - even if we didn't have a hazardous location involved.
 
adamsmithpr said:
I am also using PVC under the building at less than 24" of cover but because of some condition we can't increase the range.
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Is that PVC also a run into the hazardous location(s)? Did not read up on requirements, but I believe you could go less depth on such runs but would need to convert back to RMC/IMC.
 
kwired said:
Is that PVC also a run into the hazardous location(s)? Did not read up on requirements, but I believe you could go less depth on such runs but would need to convert back to RMC/IMC.
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Agreed, IMO the code specifically says you need 24" of cover to use PVC going to a classified location. Being under a building does not change that requirement (although I've seen inspectors let it fly, conduit that "others" stubbed out of the building for me to pick up).
 
adamsmithpr said:
I am also using PVC under the building at less than 24" of cover but because of some condition we can't increase the range.
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That was discussed at length at a recent IAEI Seminar and the unanimous opinion of the moderators, some CMP members, was that doing so would be a violation. The exception in 514.8 calls for the PVC to have 24" of cover and then discusses termination.
 
If I live long enough and you fellows don't run out of patience, I may one day know how to inspect a gas station :)

2nd situation:

PVC conduit leaves the building travels underground to a point about 3ft from the dispenser..
turns up into a steel column ad extends to the top of the canopy for lighting.
The steel column is embedded in the concrete island so even though the PVC somewhat travels thru the Class 1 Div 2 area is is never actually exposed as the entire run in the classified area is either in concrete or inside a solid steel column.
Any violation ?
 
augie47 said:
If I live long enough and you fellows don't run out of patience, I may one day know how to inspect a gas station :)

2nd situation:

PVC conduit leaves the building travels underground to a point about 3ft from the dispenser..
turns up into a steel column ad extends to the top of the canopy for lighting.
The steel column is embedded in the concrete island so even though the PVC somewhat travels thru the Class 1 Div 2 area is is never actually exposed as the entire run in the classified area is either in concrete or inside a solid steel column.
Any violation ?
Click to expand...

Embedded in 2 inches of concrete usually means "not in whatever it IS in".
 
augie47
If I live long enough and you fellows don't run out of patience, I may one day know how to inspect a gas station :)

2nd situation:

PVC conduit leaves the building travels underground to a point about 3ft from the dispenser..
turns up into a steel column ad extends to the top of the canopy for lighting.
The steel column is embedded in the concrete island so even though the PVC somewhat travels thru the Class 1 Div 2 area is is never actually exposed as the entire run in the classified area is either in concrete or inside a solid steel column.
Any violation ?​
Click to expand...
I haven't done one of those for years, but did quite a few in the 1990's. We never used PVC for any of the underground then, was always IMC/RMC, but we did have a handhole in the column at least 18" high and a seal fitting accessible from handhole and non hazardous location wiring methods the rest the way up the column. I assumed that seal at or above 18" was required, at least back then that but may be wrong.
 
augie47 said:
If I live long enough and you fellows don't run out of patience, I may one day know how to inspect a gas station :)

2nd situation:

PVC conduit leaves the building travels underground to a point about 3ft from the dispenser..
turns up into a steel column ad extends to the top of the canopy for lighting.
The steel column is embedded in the concrete island so even though the PVC somewhat travels thru the Class 1 Div 2 area is is never actually exposed as the entire run in the classified area is either in concrete or inside a solid steel column.
Any violation ?
Click to expand...
You and me both :?

As I mentioned earlier, Art 514 is strongly influenced by a TC other than CMP14 and that TC has changed its mind in every NEC Edition since 2002 as evidenced by the evolution of Figure 514.3 since then. As I understand your description, if "conventional" (not NFPA 30A TC) area classification practices were used, the run would never be considered as in a classified location at all.

Personally, I would have no problem with the installation as you have described it; especially, if the run originates and terminates in an unclassified location.
 
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