Signs and outline lighting systems shall be installed so that adjacent combustible materials are not subjected to temperatures in excess of _____.
a) 60°C
b) 75°C
c) 90°C
d) 105°C
See answer and applicable Code reference
The correct answer is: c) 90°C
The Code requirements for electric signs and outline lighting systems can be found in Art. 600 of the 2011 NEC. As noted in Sec. 600.9(C), "Signs and outline lighting systems shall be installed so the adjacent combustible materials are not subjected to temperatures in excess of 90°C (194°F). The spacing between wood or other combustible materials and an incandescent or HID lamp or lampholder shall not be less than 2 in."