CMI Electrical Systems Inspection 1

Question 1

According to NEC 230.79, what is the minimum service ampacity required for a single-family dwelling?

Accepted Answer

100 amps

Answer

NEC 230.79 requires a minimum 100-amp service for single-family dwellings, though 200 amps is the modern standard for new construction.

Question 2

Which type of wiring commonly found in homes built before 1950 is flagged during inspections primarily because it lacks a ground conductor?

Accepted Answer

Knob-and-tube wiring

Answer

Knob-and-tube wiring has only two conductors (hot and neutral) with no ground wire, and its cloth insulation is often degraded, making it a safety concern.

Question 3

Under current NEC standards, bedrooms must be protected by which device to guard against arc-fault-initiated fires?

Accepted Answer

AFCI circuit breakers or combination AFCI devices

Answer

The NEC requires Arc Fault Circuit Interrupter (AFCI) protection for bedroom circuits because arcing in wiring or cords is a leading cause of residential fires.

Question 4

A home inspector observes two conductors connected under a single breaker terminal in the main panel. What deficiency does this represent?

Accepted Answer

Double-tapping: two conductors under a terminal not listed for that configuration, creating a fire and fault risk

Answer

Double-tapping means two wires share a breaker terminal not rated for dual conductors, which can cause loose connections, arcing, and overheating.

Question 5

Per NEC 240.24, the center of the operating handle of a circuit breaker in the highest position must not exceed what height from the floor?

Accepted Answer

6 feet 7 inches

Answer

NEC 240.24(A) limits the center of the grip of the operating handle to a maximum of 6 feet 7 inches (2.0 m) above the floor so breakers remain accessible.

CMI - Certified Master Inspector Practice Test

CMI - Certified Master Inspector Practice Test

CMI Electrical Systems Inspection 1