Pressurized Enclosure in Class I, Division 1 Area

[scrub12]

I am looking for some guidance on pressurizing a NEMA 12 enclosure for a Class I, Division 1 environment. Can this be done by simply adding a purged/pressurized system to an existing panel? Does the panel need to be tested by a testing agency? Any recommendations here would be helpful. Thanks in Advance!

 

[rbalex]

See NFPA 496.

Pressurization Types X & Y are the recognized protection techniques for Class I, Division 1. [NEC Section 500.7 (D)] They are definitely more rigorous than ,"...simply adding a purged/pressurized system to an existing panel?" Beyond the installation of the equipment there are some necessary operational/monitoring requirements.

 

[scrub12]

Yes, that's where it gets tricky, labeling requirements, cutting off power upon loss of pressurization, t-rating, etc. Probably best subbing out to a panel builder.

 

[petersonra]

Yes, that's where it gets tricky, labeling requirements, cutting off power upon loss of pressurization, t-rating, etc. Probably best subbing out to a panel builder.

There are companies that make listed systems for this. Best to buy one from them.

 

[MegohmMan]

volume of cabinet determine how many total air volume exchanges are required to consider the enclosure purged. Definitely consult with engineering if this is not your wheelhouse. Class1 Div1 is nothing to mess with.