Licensed Electrical Contractor Special Occupancies and Equipment Questions and Answers

Question 1

For a legally required emergency system, what is the maximum time permitted by NEC 700.12 for the emergency power source to be connected to the load after a normal power failure?

Accepted Answer

10 seconds

Answer

60 seconds

Answer

2 minutes

Answer

Immediately, with no interruption

Question 2

A 2-inch rigid metal conduit leaves a Class I, Division 1 hazardous location and enters an unclassified area. According to NEC 501.15(A)(4), where must the sealing fitting be located relative to the boundary?

Accepted Answer

On either side of the boundary, as close as practicable but no more than 10 feet from the boundary.

Answer

On the hazardous side of the boundary only, within 18 inches.

Answer

Exactly at the boundary wall, with the fitting half in each area.

Answer

Only in the unclassified area, within 24 inches of the boundary.

Question 3

Which of the following components is NOT required by NEC 680.26(B) to be bonded to the equipotential bonding grid for a permanently installed swimming pool?

Accepted Answer

A metal drinking fountain located 8 feet from the inside wall of the pool.

Answer

Metal shells of underwater luminaires.

Answer

The reinforcing steel of the pool shell.

Answer

Metal-sheathed cables and metal raceways within 5 feet horizontally of the inside walls of the pool.

Question 4

In a patient care vicinity of a hospital designated as a 'critical care (Category 1) space', which of the following is a specific requirement for branch circuits serving patient-care-related electrical equipment?

Accepted Answer

They must be wired with an insulated copper equipment grounding conductor in addition to the metal raceway.

Answer

They must be supplied by an isolated power system.

Answer

All receptacles must be of a twist-lock type.

Answer

The wiring method must be Type MI cable exclusively.

Question 5

According to NEC Article 625, what type of personnel protection is required for all 120-volt, single-phase, 15- and 20-ampere receptacles installed for the connection of electric vehicle charging equipment?

Accepted Answer

A ground-fault circuit-interrupter (GFCI) for personnel.

Answer

An arc-fault circuit interrupter (AFCI) device.

Answer

A system that monitors the charging cable and interrupts the circuit on a fault.

Answer

No special protection is required beyond a standard overcurrent device.

Question 6

A contractor is wiring a new concrete-floor dairy barn where livestock will be confined. To mitigate the effects of stray voltage, what does NEC Article 547 require to be installed in the concrete floor?

Accepted Answer

An equipotential plane bonded to the building's grounding electrode system.

Answer

A dedicated isolated grounding system for all electrical equipment.

Answer

Type UF cable embedded directly in the concrete for all circuits.

Answer

A ground-fault circuit interrupter for every 120V receptacle.