Radio and TV Equipment practice questions

Correct: A — It must be as large as the lead-in conductor, but not smaller than 10 AWG copper, bronze, or copper-clad steel

810.58(B) requires the protective bonding conductor/GEC to be as large as the lead-in, and never smaller than 10 AWG copper, bronze, or copper-clad steel. The 14 AWG minimum belongs to the operating conductor (810.58(C)); the service GEC table in 250.66 doesn't apply here, and dropping the lead-in-matching requirement ignores half the rule.

Correct: B — The minimum size listed in Table 810.16(A)

810.16(A) requires outdoor antenna conductors to be sized no smaller than given in Table 810.16(A), which is based on mechanical strength for the span, not ampacity, nearby circuit voltage, or conduit fill — antenna conductors carry negligible current.

Correct: C — 810.20(A)

810.20(A) is the general requirement that each lead-in conductor from an outdoor antenna have a listed antenna discharge unit unless it's in a grounded continuous metal shield; 810.21(F) instead governs which grounding electrode the unit's bonding conductor connects to, not whether a discharge unit is required.

Correct: D — The intersystem bonding termination

810.21(F)(1) requires connection to the intersystem bonding termination whenever one exists — the grounding-means options and a dedicated electrode only apply when there is no ITB, per 810.21(F)(2) and (F)(3).

Correct: C — Attaching the antenna to the electric service mast

810.12 specifically bars attaching antennas or lead-in conductors to the electric service mast. The other options describe compliant practice: lead-ins must be securely attached to the antenna, antennas need secure independent support, and insulators must have adequate mechanical strength.

Correct: A — Running the aluminum conductor within 300 mm (12 in.) of the earth

810.21(A) requires aluminum or copper-clad aluminum conductors installed outside to stay at least 450 mm (18 in.) from the earth; 300 mm (12 in.) violates that clearance. Copper in contact with masonry is fine — the masonry/earth contact restriction applies only to aluminum and copper-clad aluminum. Copper-clad steel and bronze are both explicitly permitted materials with no such earth-contact restriction.

Correct: D — In as straight a line as practicable

810.21(E) requires the bonding conductor or grounding electrode conductor to be run in as straight a line as practicable. Restricting it to inside the building isn't required — 810.21(G) allows either inside or outside. Insulating standoffs aren't required by 810.21(C), and routing along metal raceways isn't a requirement of this section.

Correct: A — Through a drilled window pane

810.55 lists a drilled window pane as one of the three approved entrances. A purpose-made opening must provide at least 2 in. (50 mm) clearance, not 1 in., and the section specifies a rigid, noncombustible, nonabsorbent insulating tube or bushing, not just any sealed opening.

Correct: C — 600 mm (2 ft)

810.18(A) requires 600 mm (2 ft) of clearance from power conductors of 250 volts or less between conductors. The 100 mm (4 in.) option only applies to permanently separated circuits under 150 volts, the 3.0 m (10 ft) option applies to circuits over 250 volts, and the 1.8 m (6 ft) option is the lightning protection clearance, not the general power-conductor clearance.

Correct: C — Over 350 volts between conductors

810.71(C) sets the threshold at over 350 volts between conductors, not 150 volts to ground (a threshold used elsewhere in the NEC for other equipment), not 600 volts, and not simply any voltage present.

Correct: C — 100 mm (4 in.)

810.70 sets the default separation at 100 mm (4 in.) unless one of the listed exceptions applies. The other spacing values aren't the figure this section specifies.

Correct: C — Table 810.52

810.52 requires outdoor antenna conductors to be sized not less than given in Table 810.52. Tables 250.66 and 310.16 govern grounding electrode and ampacity sizing, and Article 800 covers communications circuits, not antenna conductors.