Class1 Haz 2

[mike ryder]

I am wanting to know if raising all nema 1 enclosers and receptacles up to a min of 4' AFF, in Class 1 Haz 2 rooms, where the customer tells us the gas will never rise above 18", is a possible resolution to changing out all the devices in the rooms?

 

[kwired]

Assuming you mean class 1 division 2.

What is the application? This is common practice and is even mentioned in the NEC for places like commercial garages or even around fuel dispensers.

The determining factor is if the classified area boundary is determined to be 18 inches above the floor or grade. That may or may not be the owners call to make. It is defined by NEC for locations like I mentioned before, but NEC doesn't define boundaries for all classified locations and you may need other codes or authorities to define the boundaries.

 

[rbalex]

I want to endorse kwired's response and add a comment or two of my own.

Unless the classification is/was consistent with Articles 511-516, the classification should be done per one of the references in Section 500.4(B) IN/FPNs and it must be documented per Section 500.4(A) in any case. FedOSHA and most State OSHA require his too.

Even if the classification is correct, it is possible there may be some minor boundary seal issues; we would need to know the basis of classification.