Electrical Systems & Safety Flashcards

What is the minimum clearance required between the top of a residential electrical panel and the ceiling?

Answer: 6 feet

NEC requires a minimum headroom clearance of 6 feet above electrical panels to allow safe working access.

A home inspector observes double-tapped circuit breakers in a panel. What does this mean?

Answer: Two wires are connected to a single breaker terminal not rated for it

Double-tapping means two conductors are connected to a breaker terminal designed for only one, which is a safety defect unless the breaker is listed for two conductors.

Which wire color in a standard 120V residential circuit is the grounded conductor?

Answer: White

The white wire is the grounded (neutral) conductor in a standard 120V residential circuit.

What does an open ground condition mean at a three-prong receptacle?

Answer: The ground wire is missing or not connected

An open ground means the equipment grounding conductor is absent or disconnected, leaving no path for fault current.

InterNACHI inspectors should report aluminum branch circuit wiring (post-1972) because it poses what risk?

Answer: Connections can loosen over time causing overheating and fire

Aluminum wiring connections can oxidize and loosen, increasing resistance and creating a fire hazard at termination points.

What is the standard amperage rating for a 240V dryer circuit in a residential home?

Answer: 30 amps

A 240V electric dryer circuit is typically protected by a 30-amp double-pole breaker per NEC requirements.

A home inspector finds a Federal Pacific Stab-Lok electrical panel. What should the inspector note?

Answer: These panels have a documented history of breaker failure and fire risk

Federal Pacific Stab-Lok panels have a well-documented history of failing to trip under overcurrent conditions, posing a fire hazard.