CRC CRC Electrical, Plumbing & Mechanical Systems 2

Question 1

A residential contractor is installing a 200-amp service panel. What minimum wire gauge is required for aluminum service entrance conductors at this ampacity?

Accepted Answer

2/0 AWG aluminum

Answer

For a 200-amp service, 2/0 AWG (double-ought) aluminum conductors are the NEC-approved minimum size for service entrance cables.

Question 2

What is the purpose of a 'expansion tank' in a closed-loop residential water heater system?

Accepted Answer

To absorb thermal expansion of heated water and prevent pressure buildup

Answer

When a backflow preventer creates a closed system, an expansion tank absorbs the volume increase from heated water, preventing unsafe pressure spikes in the plumbing.

Question 3

Which type of duct insulation is required when supply ducts pass through an unconditioned attic space?

Accepted Answer

Minimum R-8 insulation per the IECC

Answer

The International Energy Conservation Code (IECC) requires supply ducts in unconditioned attics to be insulated to at least R-8 to minimize heating and cooling losses.

Question 4

A homeowner complains of a 'water hammer' — loud banging pipes when a faucet is turned off. What is the best remedy?

Accepted Answer

Install water hammer arrestors near the affected fixtures

Answer

Water hammer arrestors contain a chamber with an air cushion that absorbs the pressure wave created when water flow is suddenly stopped, eliminating pipe banging.

Question 5

When sizing a residential HVAC system, what is the primary calculation method used to determine heating and cooling loads?

Accepted Answer

Manual J load calculation

Answer

ACCA Manual J is the industry-standard protocol for calculating residential heating and cooling loads based on climate, insulation, windows, occupancy, and other factors.

(CRC) Certified Residential Contractor Practice Test

(CRC) Certified Residential Contractor Practice Test

CRC CRC Electrical, Plumbing & Mechanical Systems 2