Master Electrician Exam (NEC)Special Occupancies, Equipment, and ConditionsEasy
A master electrician is installing a new emergency lighting system in a commercial building. According to NEC, what is the maximum time allowed for the emergency lighting system to come online and supply illumination after the normal power supply fails?
- A5 seconds
- B30 seconds
- C60 seconds
- D10 seconds
Show answer & explanationAnswer & explanation
Correct answer: D. 10 seconds
NEC Section 700.12(B)(2) specifies that emergency illumination shall be provided within 10 seconds of the normal power supply failure. This ensures prompt illumination for safety during power outages.
Why the other options are wrong
- A. This is too fast; the NEC allows more time for emergency systems to activate.
- B. This duration is too long for emergency lighting; rapid activation is critical for safety.
- C. This duration is significantly too long and would not meet the safety requirements for emergency systems.
Emergency System Activation Time
The maximum time permitted by NEC for an emergency lighting system to provide illumination after the failure of the normal power supply.
- Ensures immediate safety during power outages.
- Critical for egress and occupant safety.
- NEC Article 700 covers emergency systems.
Memory trick: Ten seconds to light up the dark, safety's mark!