If the emergency function wiring is Class C, is this allowed in NFPA 90A compliant installations?

If the emergency function wiring is Class C, is this allowed in NFPA 90A compliant installations?

• A. Yes
• B. No
• C. Only in older buildings
• D. Only in new constructions

Answer: (B)

NFPA 90A makes sure emergency functions—like automatic smoke control, dampers, and other critical HVAC safety features—have wiring that will stay powered and operable under fire conditions. Class C does not meet the requirements for emergency-function wiring in NFPA 90A, so it cannot be used in a compliant installation. In other words, the standard requires approved emergency-function wiring types that provide the necessary reliability and continuity, and Class C isn’t one of those approved options.

NFPA 90A makes sure emergency functions—like automatic smoke control, dampers, and other critical HVAC safety features—have wiring that will stay powered and operable under fire conditions. Class C does not meet the requirements for emergency-function wiring in NFPA 90A, so it cannot be used in a compliant installation. In other words, the standard requires approved emergency-function wiring types that provide the necessary reliability and continuity, and Class C isn’t one of those approved options.