# Gas Station Wiring



## RIVETER (Sep 26, 2009)

I am not the resident expert on explosion proof, but I would like to ask a couple of more questions. The canopy you are referring to, is it the very high canopy over all, or just over the pumps at about ten feet high? Are you running GRC? Is the chase that you would use to get to the canopy at least 20' away from a pump? Where is the contactor for the lights located?


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## Gamit (Dec 30, 2009)

RIVETER said:


> I am not the resident expert on explosion proof, but I would like to ask a couple of more questions. The canopy you are referring to, is it the very high canopy over all, or just over the pumps at about ten feet high? Are you running GRC? Is the chase that you would use to get to the canopy at least 20' away from a pump? Where is the contactor for the lights located?


Im assuming the pipe feeding the lights is within the 20 foot zone and going straight up to feed the lights,witch are all fed with same conduit run maybe at 15' high. If that was the case where exactly would you seal the the conduit? And would you seal each individual fixture? My biggest question is there a height requirement regarding explosion proof?


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## CTshockhazard (Aug 28, 2009)

If the conduit for the lighting didn't pass through the classified location, it wouldn't need any seal at all as the fixtures are not in the classified area.

These conduits typically do pass through the zone and require a seal within 10' of the boundary.

See 514.8 and 514.9(B) which refers you to 501.15(A)(4) and (B)(2). ('05 NEC)


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## Gamit (Dec 30, 2009)

CTshockhazard said:


> If the conduit for the lighting didn't pass through the classified location, it wouldn't need any seal at all as the fixtures are not in the classified area.
> 
> These conduits typically do pass through the zone and require a seal within 10' of the boundary.
> 
> See 514.8 and 514.9(B) which refers you to 501.15(A)(4) and (B)(2). ('05 NEC)


So the 10 foot is the height limitation? Anything above does not need to be sealed?


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## CTshockhazard (Aug 28, 2009)

Gamit said:


> So the 10 foot is the height limitation? Anything above does not need to be sealed?


There really is no height limitation as to what needs a seal. See the diagram in figure 514.3. The boundary is 18" above grade in a 20' radius from the dispenser, and 18" around the dispenser up to it's height.

If your feeding something in the zone, you need a seal.

If you have conduit passing through the zone, you need a seal.

The seal can be on either side of the boundary, but must be within 10' of the boundary. Also, with the exception of listed explosionproof reducers, the seal must be the first fitting where the conduit emerges from grade.


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## Henderson (Mar 28, 2010)

*Canopy seal*

Yes I agree with the 20' rule ect, However rember that when entering the canopy location a seal is required as the first fitting entering this area!


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## Gamit (Dec 30, 2009)

Henderson said:


> Yes I agree with the 20' rule ect, However rember that when entering the canopy location a seal is required as the first fitting entering this area!


I can't find that in the 2008 NEC?


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## Henderson (Mar 28, 2010)

*Seal Off's*

Ok well in most cases that I have seen the canopy is in fact over the hazardous location right? And the wiring that is entering that location is also most likely within 20'. However it did just pop in my mind what kind of location is this? But take a look at Table 514.3(b)(1). Let me know if this helps.


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## Gamit (Dec 30, 2009)

Henderson said:


> Ok well in most cases that I have seen the canopy is in fact over the hazardous location right? And the wiring that is entering that location is also most likely within 20'. However it did just pop in my mind what kind of location is this? But take a look at Table 514.3(b)(1). Let me know if this helps.


Yes,I have looked at this table numerous times and still see no mention of any height? This NEC should be rewritten it's very unclear and confusing! If you look at figure 514.3 is that telling you 20' horizontally or in every direction including up?


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## CTshockhazard (Aug 28, 2009)

Gamit said:


> Yes,I have looked at this table numerous times and still see no mention of any height? This NEC should be rewritten it's very unclear and confusing! If you look at figure 514.3 is that telling you 20' horizontally or in every direction including up?


The 20' horizontal Class I, Div. 2 zone applies to the area between grade and 18" above grade.

There is an additional 18" horizontal Class I, Div. 2 zone that encircles the dispenser to it's height.


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## Gamit (Dec 30, 2009)

CTshockhazard said:


> The 20' horizontal Class I, Div. 2 zone applies to the area between grade and 18" above grade.
> 
> There is an additional 18" horizontal Class I, Div. 2 zone that encircles the dispenser to it's height.


Yes,encircles the dispenser horizontally... Still after all these posts there is no explanation above the 18". I give up just will have to guess this question


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## Henderson (Mar 28, 2010)

*Hazardous*

Hey bud don't give up I think of it this way it's a 20' circle you don't need a seal vertical since you installed one at the point of entry into the hazardous location at this point you should be good to go! :thumbsup:


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## professor poptart (Mar 2, 2010)

The vertical boundry of the hazordous area is 18" above grade inside the 20' radius of the dispensing units unless you are within 18" of the unit. There the vertical boundary is 18" above the pump.


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