NEMA OS 4

Description / Abstract: This standard establishes a performance test and classification scheme for outlet boxes: wall boxes, ceiling boxes, and floor boxes used for electrical and communication applications having design provisions for reducing the flow of air (air leakage) through the box and at its installed interface with the building structure, when installed as intended for normal use as instructed by the manufacturer.

The classification scheme in this standard meets the intent of the International Energy Conservation Code (IECC) and covers boxes installed in walls, ceilings, and floors where an air barrier is required.

This standard does not cover design or performance of electrical outlet boxes that are addressed in ANSI/UL 514A, CSA C22.2 No.18.1, NMX-J-023-ANCE, ANSI/UL 514C, CSA C22.2 No.18.2, ANSI/NEMA OS1, ANSI/NEMA OS2, IEC 60670-1, IEC 60670-21, or IEC 60670-23.

This standard does not cover environmental classifications for boxes or enclosures addressed in ANSI/UL 50E, CSA C22.2 No. 94.2, or NMX-J-235/2-ANCE.