InterNACHI - International Association of Certified Home Inspectors Electrical Systems and Safety Questions and Answers

Question 1

An inspector opens a main service panel and observes two white neutral conductors terminated under a single screw on the neutral bus bar. Which of the following is the most accurate description of this defect?

Accepted Answer

Double-tapped neutrals

Answer

This condition is commonly called "double-tapped neutrals." Most panelboard lugs are designed for only one conductor. Terminating two wires under one screw can lead to a loose connection over time due to expansion and contraction, which can cause overheating, arcing, and a potential fire hazard.

Question 2

According to the National Electrical Code (NEC), what is the minimum required clear working space in front of a residential electrical panel?

Accepted Answer

36 inches deep and 30 inches wide

Answer

The NEC Section 110.26 requires a clear working space of at least 36 inches of depth in front of the panel, 30 inches of width (or the width of the equipment, whichever is greater), and a height of 6.5 feet. This space allows a service person to work safely and provides an escape path in an emergency.

Question 3

While inspecting a home built in 1935, an inspector observes electrical wiring consisting of single insulated conductors supported by white ceramic knobs and protected by ceramic tubes where they pass through wood framing. What is a primary safety concern associated with this type of wiring?

Accepted Answer

It was designed to dissipate heat in open air and becomes a fire hazard if covered by thermal insulation.

Answer

This describes knob-and-tube wiring. A major hazard is that the system was designed for heat to dissipate into open air. When modern thermal insulation is blown or packed around it, the wires can overheat, leading to the breakdown of their insulation and creating a significant fire risk. Other concerns include the lack of a ground wire and damage from improper modifications.

Question 4

In a modern home, which of the following locations requires receptacles to have BOTH arc-fault (AFCI) and ground-fault (GFCI) protection?

Accepted Answer

Kitchens and laundry areas

Answer

The National Electrical Code requires AFCI protection for 15- and 20-amp branch circuits in most living areas of a dwelling, including kitchens and laundry rooms, to protect against fire hazards from arcing. It also requires GFCI protection for receptacles in locations with a high risk of shock, such as those near water in kitchens and laundry areas. Therefore, these locations require both forms of protection.

Question 5

What is the primary safety purpose of bonding the metallic gas piping system to the electrical system's grounding electrode system?

Accepted Answer

To create an equipotential plane, preventing a voltage difference between the gas pipe and other grounded objects during a fault or lightning strike.

Answer

Bonding connects all metallic systems (gas pipes, water pipes, etc.) to the electrical ground to keep them at the same electrical potential. In the event of a lightning strike or an electrical fault that energizes the piping, this connection prevents a dangerous voltage difference from developing between the pipe and another grounded appliance, which could cause an arc and potential fire or explosion. The gas pipe must be bonded, but it is prohibited from being used as the grounding electrode itself.

(InterNACHI) International Association of Certified Home Inspectors Practice Test

(InterNACHI) International Association of Certified Home Inspectors Practice Test

InterNACHI - International Association of Certified Home Inspectors Electrical Systems and Safety Questions and Answers