FREE NEC Electrical Questions and Answers

Question 1

Metal water pipes shall be bonded to  _____ when they are put in or attached to a building or structure.

Accepted Answer

any of the following

Answer

NEC 250.104(A)(1) mandates that metal water piping systems installed in or attached to a building or structure must be bonded to the service equipment enclosure, the grounded conductor at the service, the grounding electrode conductor, or one or more grounding electrodes used. This comprehensive bonding ensures that all conductive parts are at the same electrical potential, preventing dangerous voltage differences during a ground fault and minimizing the risk of electric shock.

Question 2

When Type AC armored cable is installed parallel to the sides of rafters, studs, or floor joists in an accessible attic, .

Accepted Answer

neither guard strips nor running boards shall be required

Answer

NEC 320.23(A)(2) specifies that when Type AC armored cable is installed in an accessible attic and run parallel to the sides of rafters, studs, or floor joists, neither guard strips nor running boards are required. In this orientation, the cable is considered sufficiently protected by its proximity to the structural members. This simplifies installation while still ensuring adequate protection against physical damage.

Question 3

The manual switch for controlling the emergency lighting systems in a movie theater is usually permitted to be located .

Accepted Answer

in an accessible location in the lobby

Answer

NEC 700.20 requires switches for emergency lighting to be accessible only to authorized persons. For places of assembly like movie theaters, the manual switch for controlling emergency lighting systems is typically permitted in an accessible location in the lobby. This placement ensures that authorized personnel can quickly activate or test the system in an emergency, while also being in a controlled environment to prevent unauthorized tampering.

Question 4

For use in PV source circuits within the PV array, single-conductor cable such as  _____ and single-conductor cable listed and labeled as solar
 photovoltaic (PV) wire are permitted.

Accepted Answer

USE-2

Answer

NEC 690.31(C) permits the use of specific single-conductor cables, such as Type USE-2, Type RHW-2, Type XHHW-2, and single-conductor cable listed and labeled as solar photovoltaic (PV) wire, for PV source circuits within the PV array. These cable types are designed to withstand the harsh outdoor conditions, including UV exposure, moisture, and temperature extremes, ensuring the durability and safety required for photovoltaic installations.

Question 5

All single-phase, 125-volt, 15- and 20-ampere receptacles installed within six (6) feet of the top inside edge of the bowl of sinks located 
in  _____, must have GFCI protection for dwelling units.

Accepted Answer

all of these areas

Answer

NEC 210.8(A)(7) mandates GFCI protection for all 125-volt, single-phase, 15- and 20-ampere receptacles installed within 6 feet of the top inside edge of the bowl of a sink in dwelling unit bathrooms, garages, laundry areas, utility rooms, basements, and wet bar sinks. This comprehensive requirement ensures crucial protection against electric shock in various wet and potentially hazardous areas within a dwelling unit.

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FREE NEC Electrical Questions and Answers