Frederick Cox
Member
Query: Has anyone recently installed Reloc-type modular wiring systems and boxes in an access floor system which is used as a Supply Air plenum?
Background: 2011 NEC 300.22(C) permits rated wiring methods in a plenum, but it only mentions return air plenums. It gets a little blurry when I try to distinguish whether NEC sees 'supply' and 'return' air plenums differently. I believe that NFPA 90A now defines a 'plenum' as either supply, return, exhaust, OSA and mixed airflow systems - essentially any air passage other than ductwork. Thanks!
Background: 2011 NEC 300.22(C) permits rated wiring methods in a plenum, but it only mentions return air plenums. It gets a little blurry when I try to distinguish whether NEC sees 'supply' and 'return' air plenums differently. I believe that NFPA 90A now defines a 'plenum' as either supply, return, exhaust, OSA and mixed airflow systems - essentially any air passage other than ductwork. Thanks!