Natural Gas Compressor/Dispenser station

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augie47

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I'm waiting on classification clarification but there are things here that bother me such as the LFMC.
Any input ?

Nat Gas 3.jpg
Natral Gas 2.jpg
Nat Gqas 2.jpg
 

augie47

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The picture (3) is a compressor type device, not a dispenser...
 

augie47

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I though it was the interior of the equipment in picture 1....sorry about that.

I should have provided details.. my bad

How about picture 1?

;)

Picture 1 is and overall view. Dispenser toward the front, storage tank and the compressor (pump_) adjacent. Pic 3 is the interior of the pump assembly.
It may be Class 1 Div 2.. If so, with the shock mounts, on could say "limed flexibility" is required per 510.(B)(2).
I post in hopes someone had already whupped this puppy in their area.
 

don_resqcapt19

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If the interior of the dispenser, likely with less potential leak points, has to be Class I, Division 1, I would think the interior of the compressor station should be too.
 

nhee2

Senior Member
Location
NH
NFPA 52 only specifies Div. 2 within 15 feet of compression equipment. If this is like other packaged CNG compressors I have seen, there is a cooling fan internal which provides significant ventilation within the compressor enclosure along with a combustible gas detector which will shutdown the unit on a gas leak. Also since I assume this is a pre-packaged skid from the mfr., does Chapter 5 apply?
 

augie47

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Location
Tennessee
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State Electrical Inspector (Retired)
NFPA 52 only specifies Div. 2 within 15 feet of compression equipment. If this is like other packaged CNG compressors I have seen, there is a cooling fan internal which provides significant ventilation within the compressor enclosure along with a combustible gas detector which will shutdown the unit on a gas leak. Also since I assume this is a pre-packaged skid from the mfr., does Chapter 5 apply?

Thanks for the link.
Some of the wiring is field installed .
also of concern is the lack of a motor disconnect.

Assuming the area is Class 1 Div 2. 501.10 permits LFMC but 501.30 requires equipment bonding jumpers with the LFMC.
IF the installer has provided a wire type equipment ground as part of the installation, is the bonding jumper still needed ?
 
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nhee2

Senior Member
Location
NH
NFPA 52 only specifies Div. 2 within 15 feet of compression equipment. If this is like other packaged CNG compressors I have seen, there is a cooling fan internal which provides significant ventilation within the compressor enclosure along with a combustible gas detector which will shutdown the unit on a gas leak. Also since I assume this is a pre-packaged skid from the mfr., does Chapter 5 apply?

I would have said that the EGC within the flex conduit would be sufficient but in looking at the section you quoted I don't see anything allowing elimination of the bonding jumper.

In looking at the photos again I am also wondering about the seal fitting location - if you assume the area shown is Division 2, and also assume that the underground conduit run comes back up above grade in a non-classified location, then those seals would be boundary seals and would have to be the last fitting leaving the area (the LBY fittings are between the boundary and the seal in the picture).
 

augie47

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Tennessee
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State Electrical Inspector (Retired)
I would have said that the EGC within the flex conduit would be sufficient but in looking at the section you quoted I don't see anything allowing elimination of the bonding jumper.

That was my first read but then in re-reading I found "shall not be used as the sole ground fault return path" so I am unsure. Art 500 is a challenge for me.
In looking at the photos again I am also wondering about the seal fitting location - if you assume the area shown is Division 2, and also assume that the underground conduit run comes back up above grade in a non-classified location, then those seals would be boundary seals and would have to be the last fitting leaving the area (the LBY fittings are between the boundary and the seal in the picture).

Agree. The sealoffs should be the 1st fitting inside the boundary. Not an easy fix now with the
concrete.
 

don_resqcapt19

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Illinois
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retired electrician
501.30(B) refers to 250.102 and 250.102(E)(1) clearly permits an external or internal bonding jumper. It appears that the internal EGC is permitted to be the required bonding jumper.

That being said, the common specs used around her for these types of applications require both the internal EGC and an external bonding jumper for LFMC installed in classified locations.
 
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