InterNACHI Electrical Systems and Safety 3

Question 1

What amperage rating is typically required for a dedicated 240V circuit serving a modern electric clothes dryer?

Accepted Answer

30 amps

Answer

Electric clothes dryers require a dedicated 30-amp, 240V circuit with a 4-wire connection per current NEC standards.

Question 2

An inspector observes a junction box in a basement ceiling that has no cover plate. What is the correct finding?

Accepted Answer

A deficiency — all junction boxes must have accessible cover plates

Answer

All junction boxes must have a cover plate installed to contain arcing or sparks and provide access for future maintenance.

Question 3

Which of the following conditions would indicate reverse polarity at a 120V receptacle?

Accepted Answer

The hot and neutral wires are connected to the wrong terminals

Answer

Reverse polarity occurs when the hot wire is connected to the neutral (wide) slot and the neutral to the hot (narrow) slot, creating a shock hazard.

Question 4

In a residential electrical system, what is the purpose of an anti-oxidant compound applied to aluminum wiring connections?

Accepted Answer

To prevent oxidation that increases resistance at connections

Answer

Anti-oxidant compound prevents the formation of aluminum oxide at connections, which increases resistance and creates heat buildup.

Question 5

What minimum wire gauge is required for a 20-amp branch circuit using copper conductors?

Accepted Answer

12 AWG

Answer

12 AWG copper wire is rated for 20-amp circuits; using 14 AWG on a 20-amp breaker is undersized and a fire hazard.

(InterNACHI) International Association of Certified Home Inspectors Practice Test