Electrical System Design & Installation Flashcards
7 cards from real Licensed Electrical Contractor practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Electrical System Design & Installation flashcards as text
What is the minimum headroom required in front of electrical equipment rated over 600V in an electrical room, per NEC 110.34?
Answer: 6.5 feet
NEC 110.34(A) requires a minimum headroom of 6.5 feet in front of electrical equipment rated over 600V in electrical rooms.
When designing a service entrance for a large commercial building, which factor primarily determines whether a single or multiple service drops are permitted?
Answer: Occupancy type and special conditions defined in NEC 230.2
NEC 230.2 limits buildings to one service, but lists specific exceptions including capacity, fire protection, and different occupancies that permit multiple services.
For a dwelling unit kitchen, how many small appliance branch circuits are required by the NEC?
Answer: At least two 20A circuits
NEC 210.11(C)(1) requires at least two 20A small appliance branch circuits for kitchen receptacles in dwelling units.
Which raceway system is specifically designed for use in corrosive environments such as chemical plants or wastewater treatment facilities?
Answer: Schedule 80 PVC conduit
Schedule 80 PVC conduit provides excellent resistance to corrosion from chemicals, moisture, and acids, making it ideal for corrosive industrial environments.
A voltage drop of more than 5% from service entrance to the farthest outlet on a branch circuit is generally considered:
Answer: Excessive per NEC informational notes recommending 3% max for branch circuits
NEC 210.19(A) informational notes recommend no more than 3% voltage drop on branch circuits and 5% total from service entrance to utilization point.
In a hospital electrical system design, which essential system branch provides power to critical care areas and life safety equipment?
Answer: Life safety branch
Per NEC 517.33, the life safety branch supplies power to lighting and alarms necessary for the safety of patients and staff in a hospital.
When installing a panelboard in a commercial occupancy, what is the maximum number of overcurrent devices (poles) allowed in a single panelboard per NEC 408.15?
Answer: 42 poles
NEC 408.15 limits the number of overcurrent devices in a panelboard to a maximum of 42 poles (not counting the main breaker).