CRC CRC Electrical, Plumbing & Mechanical Systems

Question 1

In residential wiring, what is the maximum number of 20-ampere branch circuits required to serve kitchen counter receptacles per the NEC?

Accepted Answer

At least two small-appliance circuits

Answer

The NEC requires a minimum of two 20-ampere small-appliance branch circuits to supply all receptacles serving countertop surfaces in the kitchen.

Question 2

A residential plumber installs a P-trap below a lavatory sink. What is the P-trap's primary function?

Accepted Answer

To hold water that blocks sewer gases from entering the home

Answer

The water retained in the P-trap creates a seal that prevents hazardous sewer gases (like hydrogen sulfide and methane) from traveling back through the drain into the living space.

Question 3

What type of HVAC system circulates conditioned air through a network of ducts to multiple rooms in a home?

Accepted Answer

Forced-air system

Answer

A forced-air system uses a furnace or air handler to move conditioned air through supply and return ducts, distributing heating or cooling throughout the home.

Question 4

When installing electrical outlets in a bathroom, the NEC requires them to be protected by which device?

Accepted Answer

Ground Fault Circuit Interrupter (GFCI)

Answer

The NEC mandates GFCI protection for all receptacles in bathrooms because water proximity creates an elevated shock hazard; GFCI devices cut power within milliseconds of detecting a ground fault.

Question 5

What is the minimum slope required for a residential drain pipe to ensure proper drainage per most plumbing codes?

Accepted Answer

1/4 inch per foot (2% grade)

Answer

A minimum slope of 1/4 inch per foot (approximately 2%) is required for drain lines 3 inches or smaller to maintain adequate flow velocity and prevent solids from settling.

(CRC) Certified Residential Contractor Practice Test

(CRC) Certified Residential Contractor Practice Test

CRC CRC Electrical, Plumbing & Mechanical Systems