THW insulation has a _____ rating when installed within electric-discharge lighting equipment, such as through fluorescent luminaires.
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
Conductor construction and application rules are outlined in Table 310.104(A) through Table 310.104(E) of the 2011 NEC. As noted in Table 310.104(A), THW insulation has a 90°C rating when installed within electric-discharge lighting equipment.
Mike Holt is the owner of Mike Holt Enterprises (www.MikeHolt.com), one of the largest electrical publishers in the United States. He earned a master's degree in the Business Administration Program (MBA) from the University of Miami. He earned his reputation as a National Electrical Code (NEC) expert by working his way up through the electrical trade. Formally a construction editor for two different trade publications, Mike started his career as an apprentice electrician and eventually became a master electrician, an electrical inspector, a contractor, and an educator. Mike has taught more than 1,000 classes on 30 different electrical-related subjects — ranging from alarm installations to exam preparation and voltage drop calculations. He continues to produce seminars, videos, books, and online training for the trade as well as contribute monthly Code content to EC&M magazine.
