We do 80,000 to 100,000 sq ft supermarkets in NM.

These have suspended ceilings but have hard duct HVAC returns so it is not "other space used for environmental air" MA amended the change in the 2002 NEC so that NM above a commercial suspended ceiling is still OK.

From a personal stand point I think it is a bogus installation. [Linked Image]

480 volt 3 phase roof top units fed with 12/3 NM strung through the steel joists.

Have you noticed how thin the outer jacket is getting on NM lately?

IMO it unlikely after installing thousands of feet of NM in these steel frame buildings that some of it will not be damaged.

This is starting to change more of these stores are going MC now.

Bob Badger
Construction & Maintenance Electrician
Massachusetts