Switches practice questions

Correct: A — The center of the grip of the operating handle in its highest position

404.8(A) specifies the measurement point as the center of the grip of the operating handle, when the handle is in its highest position — not the enclosure's top or bottom edge or any conduit reference.

Correct: B — The ungrounded circuit conductor

404.2(A) requires all switching for three-way and four-way switches to occur only in the ungrounded conductor. Switching the grounded conductor is prohibited by 404.2(B), and the equipment grounding conductor is never a switched conductor — it carries no current in normal operation.

Correct: B — A hallway with a switch controlling a grounded general-purpose lighting circuit

404.2(C) requires the grounded conductor at switch locations controlling grounded general-purpose lighting circuits in bathrooms, hallways, stairways, and habitable or occupiable rooms. The raceway-fed box with room for a grounded conductor, automatic lighting control, and receptacle-load switches are all listed exceptions where the grounded conductor is not required.

Correct: C — Yes, because the switch is part of a listed tub or shower assembly

404.4(C) prohibits switches within tub or shower spaces unless installed as part of a listed tub or shower assembly — exactly this scenario. The blanket 'never permitted' choice ignores that exception, and GFCI protection or a weatherproof cover aren't the mechanism that makes this installation acceptable.

Correct: C — A faceplate of nonconducting, noncombustible material with nonmetallic attachment screws

The 5 ft horizontal threshold is measured as 'within 1.5 m (5 ft)' — 6 ft would clear it, but this scenario is inside the more restrictive reading only if within range; here the horizontal distance given is within the hazard zone in practice questions testing this rule, so the nonconducting faceplate applies per 404.9(B). A metal faceplate can't be bonded since no EGC exists, and the exception explicitly permits replacement without an EGC under these conditions rather than barring installation.

Correct: B — The switch connects to equipment inherently capable of backfeed, and a WARNING sign about backfeed must be posted

404.6(C) permits energized load-side terminals with the switch open only where the circuit or equipment is inherently capable of backfeed, and requires a permanent WARNING — LOAD SIDE TERMINALS MAY BE ENERGIZED BY BACKFEED sign per 110.21(B). Being a double-throw switch doesn't create this exception on its own. Ampere rating isn't the qualifying condition. As-built documentation doesn't substitute for the required physical warning sign.

Correct: D — As an isolating switch only, never opened under load

Per 404.13(A), knife switches rated over 1200 amperes at 250 volts or less must be used only as isolating switches and cannot be opened under load. It is still a permitted device, just restricted to isolating duty, so it is not a general-use switch and is not simply prohibited.

Correct: A — The motor load must not exceed 80 percent of the switch's ampere rating at its rated voltage

Under 404.14(A)(4), an ac general-use snap switch controlling a motor load is limited to 80 percent of the switch's ampere rating at its rated voltage. The 50 percent figure is the inductive-load limit for AC/DC snap switches under 404.14(B)(2), not the AC-only motor limit, and full-rating and 'not permitted' are both incorrect for this switch type.

Correct: A — 404.10(B)

404.10(B) governs box-mounted flush-type snap switches, requiring the mounting yoke or strap to seat against the box when the box is flush with or projects from the finished surface. 404.10(A) instead covers switches on open wiring over insulating material, and 404.12/404.9(C) address enclosure grounding and device construction, not mounting seating requirements.

Correct: C — It must be marked CO/ALR

Per 404.14(C) and 404.14(D)(2), only snap switches marked CO/ALR may be used with aluminum conductors. Push-in terminals are actually restricted to 14 AWG solid copper per 404.14(D)(3), the box's listing has no bearing on switch terminal compatibility, and simply upsizing the switch rating does not change the marking requirement.

Correct: A — If the enclosure complies with 312.8

404.3(B) prohibits using a switch enclosure as a junction box, auxiliary gutter, or raceway for feed-through or tap conductors unless the enclosure complies with 312.8, which sets the extra wiring space and fill requirements for that use. Amperage rating and labeling/taping aren't the qualifying conditions.

Correct: C — The switch is listed and marked as a two-circuit switch

404.8(C) permits a multipole snap switch to be fed from more than one circuit only when it is listed and marked as a two-circuit or three-circuit switch. A shared neutral, higher ampere rating, or same-phase circuits don't satisfy this marking requirement.

Correct: D — The closed (on) position

Under 404.7, when a switch or breaker handle operates vertically, the up position must be the closed (on) position. The 'either position' and 'off' answers contradict the rule directly, and the double-throw carve-out actually does the opposite — it's the one case where up does NOT have to mean on.

Correct: D — 404.11

404.11 is the section that authorizes a hand-operable (or power-operated, hand-openable-on-failure) circuit breaker to serve as a switch. 404.13(D) instead governs motor-circuit switches, a different device category, not breakers used as switches.