Emergency & Standby Systems Flashcards
7 cards from real CEI practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Emergency & Standby Systems flashcards as text
When a battery-based UPS serves as the emergency source, its disconnecting means must:
Answer: Be accessible to authorized personnel and identified
NEC 700.12(A) requires that the disconnecting means for battery systems be accessible to authorized personnel and clearly identified.
Which statement best describes a 'separate service' as an emergency source under NEC 700.12(D)?
Answer: A service from a separate utility or network protector on a different utility grid section
NEC 700.12(D) permits a separate utility service as an emergency source only if it is sufficiently remote and independent so a single event cannot disable both sources.
An emergency system overcurrent device must be selected to:
Answer: Provide selective coordination with all devices above it in the emergency distribution
NEC 700.32 requires overcurrent devices in emergency systems to be selectively coordinated with all upstream devices to prevent a fault on one circuit from tripping the entire emergency system.
What is the purpose of a static transfer switch (STS) in an emergency power system?
Answer: To transfer between two utility feeds in milliseconds using solid-state devices
A static transfer switch uses solid-state switching to transfer between two power sources in milliseconds, far faster than electromechanical automatic transfer switches.
Under NEC 701.12, legally required standby power must be available within how many seconds of normal power failure?
Answer: 60 seconds
NEC 701.12 requires legally required standby systems to be capable of supplying power within 60 seconds of normal power failure.
A portable generator used as an emergency source requires which of the following to prevent backfeed to the utility?
Answer: An interlocked transfer switch or interlock kit on the service panel
An interlocked transfer switch or listed main breaker interlock prevents the generator from backfeeding the utility, protecting utility workers from electrocution.
NEC 700.5 requires emergency system equipment to be specifically identified. Which marking approach satisfies this requirement?
Answer: A permanent, durable label or marking on all enclosures, switches, and panelboards
NEC 700.5 requires all emergency system equipment to be permanently and durably marked so it can be identified during maintenance, inspection, or emergency response.