Wiring methods & materials: Texas Journeyman Electrician Practice Questions

Which NEC article covers nonmetallic-sheathed cable (Type NM)?

Type NM cable is in Article 334. 320 is armored cable (AC), 330 is metal-clad cable (MC) and 338 is service-entrance cable.

NM cable must be secured within what distance of every box, cabinet or fitting?

Secure NM cable within 12 in of each box or fitting, and at intervals of no more than 4½ ft.

Between supports, NM cable must be secured at intervals not exceeding:

The maximum spacing between supports for NM cable is 4½ ft.

EMT must be securely fastened within what distance of each box, conduit body or other termination?

EMT is fastened within 3 ft of each termination and at intervals of no more than 10 ft.

In general, the smallest conductor size permitted to be run in parallel is:

Parallel conductors are generally 1/0 AWG and larger, all the same length, material, size and insulation.

At each box, at least how much free conductor must be left for splices or device connections?

Leave at least 6 in of free conductor, measured from where it emerges from the raceway or cable; small openings also need conductors to reach 3 in outside the opening.

When counting box fill, a device yoke (such as a receptacle or switch) counts as:

Each yoke or strap counts as two conductor volumes, based on the largest conductor connected to that device.

In walls of wood or other combustible material, the front edge of a box must be:

In combustible walls the box must be flush or project; a setback of up to ¼ in is allowed only in noncombustible walls.

A metal box holds six 12 AWG insulated conductors, one receptacle on a single yoke and two equipment grounding conductors. Each 12 AWG conductor volume is 2.25 in³ (given). What is the minimum box volume?

Count conductor volumes first, then multiply by the volume per conductor.

According to the NEC, what is the general rule for the conductors of one circuit, including the grounded conductor and EGC?

Section 300.3(B) keeps all conductors of the same circuit together to limit inductive heating and keep circuit impedance low.

According to the NEC, conductors of 120/240 V and 480Y/277 V systems may share a raceway when:

Section 300.3(C)(1) allows conductors of different systems of 1000 V or less in the same raceway, cable or enclosure if every conductor's insulation is rated at least the maximum voltage applied to any conductor there.

According to the NEC, when NM cable runs through bored holes in wood studs, the edge of the hole must be at least how far from the nearest edge of the stud?

Section 300.4(A)(1) requires bored holes to be at least 1 1/4 in from the nearest edge of the wood member, so drywall screws and nails do not reach the cable.

According to the NEC, if a bored hole cannot be kept far enough from the stud edge, the cable must be protected by a steel plate at least how thick?

Section 300.4(A)(1) requires a steel plate or bushing at least 1/16 in thick (or a listed plate giving equal protection) covering the area of the wiring.

According to the NEC, where NM cable is laid in a notch cut in a wood stud, what is required?

Section 300.4(A)(2) allows cables in notches only where the notch does not weaken the structure, and requires a 1/16-in steel plate over the notch before the finish is applied.

According to the NEC, when NM cable passes through punched holes in metal studs, what is required?

Section 300.4(B)(1) requires NM cable through holes in metal framing to be protected by listed bushings or grommets securely fastened in the opening before the cable is installed.