ArcFlash 1 (20) Flashcards
Our guidance?
3DI-E60G
IEEE guidance?
IEEE 1584
The level of the hazard is defined by a ___?
calculated incident energy level
Incident energy is measured in terms of ___
Joules per square centimeter (J/cm2) or calories per square centimeter (cal/cm2).
What is arc fault current?
Lower than bolted fault current due to arc impedance.
How did we treat min fault current on Sherman-Temple MV?
Assumed as source contribution only (i.e. from UAT only without motor contribution).
How did we treat outgoing MV feeders on Sherman-Temple MV?
Did NOT cover faults on feeders. Work performed on cables would be done with breaker racked out.
With breaker racked out, any fault during operation can only be on the bus side (cable side is not hot).
How did we treat ground fault cases for MV switchgear buses on Sherman-Temple MV?
The ground fault current is limited to 400A therefore the analysis was not carried out for ground fault.
How did we treat min fault current on Sherman-Temple LV?
Assumed as source contribution only (i.e. from LC transformer only without motor contribution).
How can I tell if ETAP is reporting the arc-fault variation (85%)?
Diamond symbol, with note in lower left of the analysis report page for that particular bus.
What is the table in 70E for PPE Categories?
130.7 C E
Do we use the PPE Categories defined in 70E?
No. 70E prohibits their use when you do an incident energy analysis.
What is the Restricted Approach Boundary?
The point at which a qualified person must wear rubber gloves or take other action to protect themselves.
What is the fast trip logic of a zone interlocking scheme?
Incomer 50 is enabled when no feeder has a fault indicated.
Do we ever consider energy based on failure of first protective device?
No
