Aircraft Hangar Conduit Installed Below Floor

[rowlandct]

For Aircraft Hangars in NEC 2008, Section 513.8 (A), the code states that All wiring installed in or under the hangar floor shall comply with the requirements for Class I, Division 1 locations.

What happens if you have uninterrupted raceways that are embedded in the slab, but do not turn up into or above the hangar floor? They run from an unclassified area to an unclassified area, but are embedded in the hangar slab. Do you have to employ Class I, Div I raceway and sealing requirements on the conduits? or can you employ PVC conduits without installing seal-offs? Any help/insight would be greatly appreciated.

 

[petersonra]

For Aircraft Hangars in NEC 2008, Section 513.8 (A), the code states that All wiring installed in or under the hangar floor shall comply with the requirements for Class I, Division 1 locations.

What happens if you have uninterrupted raceways that are embedded in the slab, but do not turn up into or above the hangar floor? They run from an unclassified area to an unclassified area, but are embedded in the hangar slab. Do you have to employ Class I, Div I raceway and sealing requirements on the conduits? or can you employ PVC conduits without installing seal-offs? Any help/insight would be greatly appreciated.

If thats what it says, it would seem to be pretty clear what the requirement is.

 

[rbalex]

First, read the scope of Article 513 carefully. Depending on the fuel used, many hangars that use Class II (combustible) fuels only do not need to be classified at all.

Assuming the hangar is properly classified, then Section 513.8 requires underground wiring in or beneath the slab to be in compliance with Section 501.10 (A)(1). Most of those methods aren’t suitable for underground, but Subsection 501.10 (A)(1)(a) and it’s Exception are.

Section 513.8(B) addresses your direct question. Basically a boundary seal will be required at the point(s) of emergence.