Conduit Seal Usage

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mioduz

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Controls eng
I am having a debate with a co-worker over use of seals within a Hazardous location
Facts:

Class 1 Div 2 Area

NEMA 4 Panel with Purge Controller installed to comply with Cl1 Div 2 Required Rating

The Control cabinet needs a vortec cooler installed, and I have purchased a Cl1 Div2 rated solenoid valve to control said cooler

The solendoid (red hat) has a 1/2" conduit connection and wire leads

My Co-Workers claim is that we can directly mount the solenoid to the enclosure with a short nipple and a conduit hub, without using a seal.

I disagree with this interpretation of the NEC code and state that ALL conduit entries need a seal NO MORE than 18" away from enclosure.

Can anyone shed some light on which of us is correct?
 
The question isn't whether the solenoid needs to be sealed or not - it doesn't as nhee2 mentions above. The real issue is what's inside the NEMA 4 Panel and what the source of the purge air is. Depending on what's inside, the enclosure may not even need to be purged at all. If it does need to be purged, the air source must be from an unclassified location. See NFPA 496 for Type Z purging requirements.

(If the panel does need to be sealed, a NEMA 4 (only) enclosure would be useless; it would also need an explosionproof rating)

"I disagree with this interpretation of the NEC code and state that ALL conduit entries need a seal NO MORE than 18" away from enclosure."
This is wrong. Only enclosures that are required to be explosionproof have this requirement in Division 2. [Section 501.15(B)(1)]
 
rbalex said:
The question isn't whether the solenoid needs to be sealed or not - it doesn't as nhee2 mentions above. The real issue is what's inside the NEMA 4 Panel and what the source of the purge air is. Depending on what's inside, the enclosure may not even need to be purged at all. If it does need to be purged, the air source must be from an unclassified location. See NFPA 496 for Type Z purging requirements.

(If the panel does need to be sealed, a NEMA 4 (only) enclosure would be useless; it would also need an explosionproof rating)

"I disagree with this interpretation of the NEC code and state that ALL conduit entries need a seal NO MORE than 18" away from enclosure."
This is wrong. Only enclosures that are required to be explosionproof have this requirement in Division 2. [Section 501.15(B)(1)]
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Thank you for your input. Yes my concern was for sealing into the box.

The panel is going to be located in a Class 1 Div 2 area. The internal components of the enclosure are not Class 1 Div 2. This is why the Purge system was spec'd out to bring the ratings of enclosed components up to a Class 1 Div 2 rating. The source of the purge gas will likely be nitrogen, as they plan on using nitrogen in all of the "air operated valves".

So if I am understanding you correctly: The seal is not required as the purge would not allow ingress of hazardous gasses through the conduit fittings? (clarifying question not statement)

IF the above statement is true: Is there a limitation on the length of conduit connected before a seal is needed?

I am sorry If I am not comprehending your answers fully. Trying to get a full and complete understanding of the code.
 
mioduz said:
So if I am understanding you correctly: The seal is not required as the purge would not allow ingress of hazardous gasses through the conduit fittings? (clarifying question not statement)

IF the above statement is true: Is there a limitation on the length of conduit connected before a seal is needed?
Click to expand...
You are basically describing a “Type Z” pressurizing system per NFPA 496. Assuming your installation is consistent with NFPA 496, the inside of your enclosure is unclassified and the enclosure walls are essentially the boundary. In that case, see Section 501.15(B)(2) Exception No.3.

Note the Exception does not prohibit seals it just makes them optional. There may be reasons to seal anyway such as to maintain pressure in the enclosure. Such seals are not required to be explosionproof. See the last sentence of The main text of Section 501.15(B)(2).
 
mioduz said:
I am having a debate with a co-worker over use of seals within a Hazardous location
Facts:

Class 1 Div 2 Area

NEMA 4 Panel with Purge Controller installed to comply with Cl1 Div 2 Required Rating

The Control cabinet needs a vortec cooler installed, and I have purchased a Cl1 Div2 rated solenoid valve to control said cooler

The solendoid (red hat) has a 1/2" conduit connection and wire leads

My Co-Workers claim is that we can directly mount the solenoid to the enclosure with a short nipple and a conduit hub, without using a seal.

I disagree with this interpretation of the NEC code and state that ALL conduit entries need a seal NO MORE than 18" away from enclosure.

Can anyone shed some light on which of us is correct?
Click to expand...
First off, if your panel is already suitable for C1D2 you should not need to seal any conduits routed to it as long as they all remain in the same C1D2 zone. If they leave the zone, seal at the boundary. If the panel was required to be explosion proof (C1D1), then we'd have a different scenario, but you have already stated otherwise. Assuming the solenoid is rated for the area C1D2, I can not find a sealing requirement.... maybe I'm overlooking it
 
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