CLASS 1, DIVISION 1

[ltwright1976]

My contractor has installing rigid conduit from receptacle to receptacle and the conduit goes under the slab and stubs up to each receptacle. However, he has not put explosion proof fittings on the conduit. Doesn't the NEC require explosion proof fittings everytime he leaves the room?

 

[ssn596]

What is in the room that gives you this concern?

 

[ltwright1976]

It's a room were they store batteries. They used these batteries for military radios. I think they have lithium in them.

 

[Comcokid]

I think in this case the definition of the "room" extends for a foot or so under the slab to encompass the conduit - as long as the conduit is going nowhere else. The issue with almost all batteries (regardless of chemistry) is generation of hydrogen gas. This disperses and rises being lighter than air unlike many other flammable gases that are heavier than air and could collect in the low points (the conduit under the slab).

This is an unqualified opinion only as I do some design work on IS device internal circuits, but not the actual installations.

 

[ssn596]

Important points to consider
Room is used for battery storage
Batteries are lithium

NEC calls out for CL 1 for a foot above batteries in CHARGING areas.

Lead acid batteries emit hydrogen under charge - I do not believe you need to worry unless they are being charged.

These are lithium. I am not familiar with their charge characteristics.

You are only storing them not charging - do you really need Cl 1??

Dan Bentler

 

[dpc]

As long as the conduit is not actually entering another room, but stays in the slab, I don't think you need seals. The seals are to prevent hazardous gas from entering a non-hazardous area. But it will be up to the local AHJ.

 

[ltwright1976]

Thanks everybody for all the comments.