M Manufacturers: makers of products affected by the NEC®
U Users: users of the NEC®
I/M Installers/Maintainers: installers/maintainers of systems covered by
the NEC®
L Labor: concerned with safety in the workplace
R/T Research/Testing Labs: independent organizations developing/
enforcing standards
E Enforcing Authority: inspectors, enforcers of the NEC®
I Insurance: insurance companies, bureaus, or agencies
C Consumers: purchasers of products/systems not included in “U,”
users
SE Special Experts: provide special expertise, not applicable to other
classifications
UT Utilities: installers/maintainers of systems not covered by NEC®
