Wiring Methods & Installation Practices Flashcards

What is the minimum burial depth for rigid metal conduit (RMC) under a residential driveway?

Answer: 12 inches

RMC requires a minimum burial depth of 6 inches under a residential driveway, but 12 inches is the NEC standard for RMC under driveways subject to vehicular traffic.

Which wiring method is NOT permitted in a Class I, Division 1 hazardous location?

Answer: Flexible metal conduit (FMC)

Standard flexible metal conduit is not permitted in Class I, Division 1 hazardous locations because it cannot maintain an explosion-proof seal.

When installing EMT in a concrete slab, which requirement applies?

Answer: EMT must be coated or corrosion-resistant when encased in concrete

EMT encased in concrete must be made of steel listed for the purpose or protected by a listed corrosion-resistant coating.

What is the maximum number of 90-degree bends allowed between pull points in a conduit run?

Answer: Four 90-degree bends

The NEC limits conduit runs to a total of 360 degrees (four 90-degree bends) of bends between pull points to allow wire to be pulled without damage.

Type AC cable (armored cable) must be secured within how many inches of every box or fitting?

Answer: 12 inches

Type AC cable must be secured within 12 inches of every box, cabinet, or fitting and at intervals not exceeding 4.5 feet.

A cable installed through a floor must be protected from physical damage up to what height above the floor?

Answer: 7 feet

Cables passing through a floor must be protected by rigid metal conduit, IMC, Schedule 80 PVC, or equivalent protection to a height of 6 feet above the floor.

When installing PVC conduit exposed to sunlight, what additional requirement applies?

Answer: PVC must be listed and marked as sunlight-resistant

PVC conduit exposed to sunlight must be listed and marked as sunlight-resistant to prevent UV degradation.