Wiring methods in a transition sump with solenoid valves

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oldsparky52

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Wilmington, NC USA
I saw a picture today of some work that was done and it got me wondering.

The electrician brought in a rigid conduit into the transition sump. There is no fuel dispensing anywhere near this sump (it's at a bulkhead where they transition from underground to above ground). Each fuel line (gas and diesel) has a 120V solenoid valve in it.

The electrician installed an X-proof junction box, then came out of it with carflex to feed the solenoid valves. That's what got me to raise an eyebrow. So, is the inside of that sump "classified" by the NEC, and if so, and you know the code reference, would you please share?

I've always hard piped into the solenoid valves when gas was involved (but if it's diesel alone I'd use the flex, but sealtight for bonding purposes, not carflex). The metal solenoid only has the 2 coil wires coming out of it, so I doubt the housing is bonded.

So I guess my question is, can you use flex to the solenoid valve or no?

Thanks,
 
oldsparky52 said:
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So I guess my question is, can you use flex to the solenoid valve or no?
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The answer to this specific question is "No" if it's in Division 1, "Possibly" if it's in Division 2 and "Sure, why not?" if it's unclassified. Bonding would be an issue; it would still need a proper EGC in any case.

The explosionproof junction box brings into question whether it is a Division 2 or unclassified location. If it's classified anything other than Division 1, it is a waste of money. If it is in Division 1, it's useless if it isn't sealed properly both from the transition from grade and the LFNC to the solenoid.
 
Why would a transition sump be any different than a tank sump or a dispenser sump? All are made to capture any spills that may happen. Less likely in a transition sump depending on its position in the system. Its C1D1 to me, seal, GRSS or GRR and hard pipe or C1D1 flex. No inspector in Maine would let you get away with anything less.
 
wallyworld said:
Why would a transition sump be any different than a tank sump or a dispenser sump? All are made to capture any spills that may happen. Less likely in a transition sump depending on its position in the system. Its C1D1 to me, seal, GRSS or GRR and hard pipe or C1D1 flex. No inspector in Maine would let you get away with anything less.
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Yea, that's why I posted the question. Under normal conditions there should be no vapors. Under a small leak/drip, there would be vapors (if it's gas).

I wonder if the engineers on this site would classify the space within this sump or leave it unclassified? It would be interesting to see if there is consensus on this classification.
 
oldsparky52 said:
Yea, that's why I posted the question. Under normal conditions there should be no vapors. Under a small leak/drip, there would be vapors (if it's gas).

I wonder if the engineers on this site would classify the space within this sump or leave it unclassified? It would be interesting to see if there is consensus on this classification.
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I assume dbl wall piping, if so it's connected to every other sump in the system
 
Sumps are a somewhat unusual case. Usually, they can only be classified Division 1 or unclassified. A Division 2 classification can only be justified with a significant ventilation system.

Transitions sumps are typically part of some form of bulk storage facility operation. Bulk storage facilities (Article 515) have some rather unique requirements for classifying and treatments for underground installations. That's why I asked the question in Post #2.

Note neither Section nor Table 515.3 actually requires the underground to be Division 1 - or even classified at all. Section 515.8 has some elaborate wiring requirements for underground installations. The kicker is Section 515.9 which doesn't actually require the underground to be classified Division 1, but DOES require it to be treated like it is. This is all residue from the NFPA 30 Technical Committee's control even if it no longer brackets a reference. (See Art 515 Title, Informational Note.) CMP14 may eventually sort this all out but I think they just rely on Section 90.1(C) now.

That said, I don't believe dispensing nor Article 514 has any relevance. It's possible Article 515 doesn't either. Without a much better knowledge of the site's total installation, I would probably go along with wallyworld's analysis and note the wiring issues I identified in Post #3.
 
Thank you! (as usual)

rbalex said:
Sumps are a somewhat unusual case. Usually, they can only be classified Division 1 or unclassified. A Division 2 classification can only be justified with a significant ventilation system.

Transitions sumps are typically part of some form of bulk storage facility operation. Bulk storage facilities (Article 515) have some rather unique requirements for classifying and treatments for underground installations. That's why I asked the question in Post #2.

Note neither Section nor Table 515.3 actually requires the underground to be Division 1 - or even classified at all. Section 515.8 has some elaborate wiring requirements for underground installations. The kicker is Section 515.9 which doesn't actually require the underground to be classified Division 1, but DOES require it to be treated like it is. This is all residue from the NFPA 30 Technical Committee's control even if it no longer brackets a reference. (See Art 515 Title, Informational Note.) CMP14 may eventually sort this all out but I think they just rely on Section 90.1(C) now.

That said, I don't believe dispensing nor Article 514 has any relevance. It's possible Article 515 doesn't either. Without a much better knowledge of the site's total installation, I would probably go along with wallyworld's analysis and note the wiring issues I identified in Post #3.
Click to expand...
 
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