Compressor start batteries in hazardous areas

[scirocco_torc]

Hi. I'm posting from Australia so please excuse me if I'm not too familiar with the NEC code. I've "inherited" a 350 hp natural gas engined (recip) natural gas compressor constructed to North American electrical codes (mainly CSA approved). We've classified the hazardous area as Zone 2 (the equivalent of Class 1 Div2).

The machine has the start batteries mounted on the skid in a metal box, so the batteries, terminals and leads are within the Div 2 zone. The box and terminals do not appear to have any certification or listing. Would this be acceptable and normal practice in North America?

The reason I ask is that I'm not sure I can get an uncertified installation of this sort past the local inspector here, who is likely to want to see an ex 'e' (increased safety) enclosure and terminals, to ensure some sort of quality in the battery terminations and terminal protection. Does the NEC code have anything to say about such terminals?

 

[rbalex]

The NEC does recognize a “Zone” method of electrical area classification; however, it is not the same as the IEC method. There are several subtle differences that I’m not going to get into here. NEC, Division 2 and IEC, Zone 2 are sufficiently different in this case.

Assuming the installation were otherwise acceptable in Division 2 and the battery terminals are the only item of concern then they would not have to be modified because terminals are not considered to be arc-making under NEC rules. (I have no idea from the description if either assumption is correct.) Under IEC rules, terminals are considered to be arc-making and they would need to be “Ex e”

Edit: Minor grammatical change

 

[scirocco_torc]

Thanks very much for the reply, Bob. That was the distinction I was looking for but was not aware of.

I think the installation as a whole will probably satisfy the local inspectors due to the CSA Class 1 Div 2 approvals for the components. The only sticking points may be the battery terminals and the wiring for some non-incendive circuits, which appears to have been run using unlisted conduit/fittings, as I understand is acceptable under the NEC code. This lack of marking may not be acceptable here although I'm not sure about that at the moment.