Construction Electrical Systems in Construction 3

Question 1

What is the purpose of a 'bonding jumper' in an electrical system?

Accepted Answer

To ensure electrical continuity between metal parts of a system that may otherwise be isolated

Answer

To connect two separate electrical panels together

Answer

To reduce voltage drop over long wire runs

Answer

To balance load across two legs of service

Question 2

What type of electrical drawing shows the physical layout of equipment and wiring in a building?

Accepted Answer

Wiring plan (floor plan electrical drawing)

Answer

Schematic diagram

Answer

One-line diagram

Answer

Riser diagram

Question 3

What is the maximum voltage drop recommended by the NEC for branch circuits to minimize energy loss and equipment performance issues?

Accepted Answer

3%

Answer

1%

Answer

5%

Answer

10%

Question 4

Which phase configuration is most common for large commercial and industrial construction electrical service?

Accepted Answer

Three-phase 120/208V or 277/480V

Answer

Single-phase 120/240V

Answer

Two-phase 240V

Answer

DC 480V

Question 5

What is the function of a transformer in a construction project's temporary power distribution?

Accepted Answer

To change voltage levels from one value to another

Answer

To protect circuits from overloads

Answer

To convert single-phase to three-phase power

Answer

To measure total electrical consumption on the site

Question 6

According to NEC Article 210, what is the required height range for installing standard 15- or 20-amp receptacles in a commercial wall installation?

Accepted Answer

No specific height requirement — follow local code and architectural plans

Answer

At least 6 inches from the floor

Answer

Exactly 18 inches from the floor

Answer

Between 36 and 48 inches from the floor

Question 7

What does 'listed' mean when the NEC refers to electrical equipment?

Accepted Answer

The equipment has been evaluated by a nationally recognized testing laboratory (NRTL) and found to meet safety standards

Answer

The equipment appears on the local utility's approved product list

Answer

The equipment is listed in the project specifications

Answer

The equipment has passed a contractor's field inspection