Wiring Above Heated Ceilings

Conductors located above an electric space-heated ceiling are considered to be operating in an ambient temperature of _____.

a) 20°C
b) 30°C
c) 50°C
d) 86°C

See answer and applicable Code reference

The correct answer is: c) 50°C

Article 424 of the 2011 NEC focuses on fixed electric space-heating equipment. The rules for space-heating cables are outlined in Part V and the clearances of wiring in ceilings is noted in Sec. 424.36. The 50°C requirement is noted in this Section.