Journeyman Electrician’s Exam Journeyman Electrician's Emergency and Standby Systems 1 — Questions and Answers
Question 1: According to NEC Article 700, emergency systems must supply power within how many seconds after loss of normal power?
- 5 seconds
- 10 seconds (Correct answer)
- 15 seconds
- 30 seconds
Correct answer: 10 seconds
NEC 700.12 requires emergency systems to restore power within 10 seconds of normal power loss to protect life safety.
Question 2: Which NEC article specifically governs Legally Required Standby Systems?
- Article 700
- Article 701 (Correct answer)
- Article 702
- Article 708
Correct answer: Article 701
NEC Article 701 covers Legally Required Standby Systems, which are mandated by government agencies for safety but are not immediate life-safety emergency loads.
Question 3: What is the minimum battery operating duration required for unit equipment emergency lighting under NEC 700.12(F)?
- 60 minutes
- 90 minutes (Correct answer)
- 120 minutes
- 180 minutes
Correct answer: 90 minutes
NEC 700.12(F) requires unit equipment to maintain adequate illumination for a minimum of 90 minutes from battery backup.
Question 4: Emergency system wiring must remain entirely independent of all other wiring EXCEPT in which location?
- Transfer equipment enclosures (Correct answer)
- Panelboard enclosures
- Junction boxes
- Conduit runs shared with normal circuits
Correct answer: Transfer equipment enclosures
NEC 700.10(B)(5) specifically allows emergency and normal wiring to share an enclosure only within transfer equipment, where connection of both systems is inherently necessary.
Question 5: An automatic transfer switch (ATS) for emergency systems must be designed to:
- Allow brief parallel operation during load transfer
- Prevent interconnection of normal and emergency sources (Correct answer)
- Operate continuously at 125% of rated load
- Include integral ground fault circuit interruption
Correct answer: Prevent interconnection of normal and emergency sources
NEC 700.5(A) requires transfer equipment to prevent the inadvertent interconnection of the normal and emergency power sources to avoid backfeed and equipment damage.
Question 6: A generator used as an emergency source under NEC 700.12(B) must transfer the emergency load within:
- 5 seconds
- 10 seconds (Correct answer)
- 30 seconds
- 60 seconds
Correct answer: 10 seconds
NEC 700.12(B) specifies that engine-driven generators must start and transfer the emergency load within 10 seconds of loss of normal power.
Question 7: Which of the following loads is classified as an emergency system load under NEC Article 700?
- HVAC equipment for a commercial building
- Exit and egress lighting (Correct answer)
- Grocery store refrigeration systems
- Optional UPS for data center equipment
Correct answer: Exit and egress lighting
Exit and egress lighting is a life-safety load covered by Article 700 to ensure safe building egress during a power outage.
