NCCER Basic Electrical & Plumbing 3

Question 1

A P-trap under a sink serves what primary function?

Accepted Answer

Holding water to block sewer gases from entering the home

Answer

The P-trap holds a water seal that prevents toxic and odorous sewer gases from backing up into the living space through the drain.

Question 2

When replacing a standard light switch with a dimmer, what type of load must you verify the dimmer is rated for?

Accepted Answer

The wattage and type of bulbs (LED, incandescent, CFL)

Answer

Dimmers must be matched to the bulb type and total wattage; LED dimmers differ from incandescent dimmers, and mismatches cause flickering or fixture damage.

Question 3

What is the purpose of a pressure-relief valve (PRV) on a water heater?

Accepted Answer

To release pressure if tank pressure or temperature exceeds safe limits

Answer

The T&P (temperature and pressure) relief valve is a safety device that opens automatically to prevent catastrophic tank rupture if pressure or temperature becomes dangerously high.

Question 4

In a 240V dryer circuit, what two conductors carry current to the appliance (excluding ground)?

Accepted Answer

Two hot wires (legs) at opposite phases

Answer

A 240V circuit uses two hot legs from opposite phases of the electrical panel, each carrying 120V, to deliver 240V to the appliance.

Question 5

What material is most commonly used for residential supply water pipes in new construction today?

Accepted Answer

PEX (cross-linked polyethylene)

Answer

PEX tubing is the dominant material in modern residential plumbing due to its flexibility, freeze resistance, ease of installation, and durability.

(NCCER) National Center for Construction Education and Research Certified Handyman Practice Test

(NCCER) National Center for Construction Education and Research Certified Handyman Practice Test

NCCER Basic Electrical & Plumbing 3