Appliances practice questions

Correct: D — At least 125% of the marked rating

Under 422.10(A)(3), a continuous-load appliance (other than motor-operated) needs a branch-circuit rating of at least 125% of its marked rating unless the breaker and assembly are listed for continuous loading at 100%, which isn't the case here. 150% doesn't apply to this rule, and Table 220.55 is specific to household ranges and cooking appliances, not water heaters.

Correct: C — A cord-and-plug-connected dishwasher

422.5(A)(7) lists dishwashers as one of the seven appliance types requiring Class A GFCI protection. Clothes dryers, space heaters, and water heaters are not among the appliances listed in 422.5(A)(1) through (A)(7).

Correct: A — A humidifier directly associated with the heating equipment

422.12 permits auxiliary equipment directly associated with the heating equipment — a pump, valve, humidifier, or electrostatic air cleaner — plus permanently connected AC equipment, to share the branch circuit. A dishwasher and a general-purpose receptacle aren't associated heating auxiliaries, and fixed electric space-heating equipment is specifically excluded from this section's scope.

Correct: B — In the space adjacent to the space occupied by the dishwasher

422.16(B)(2) requires the dishwasher's receptacle to be in the space adjacent to the dishwasher's space, not within it. That in-the-space-or-adjacent allowance is the trash compactor rule, not the dishwasher rule — a common mix-up.

Correct: C — A separate disconnecting means in accordance with 422.31 must be provided

422.33(A) allows a plug-and-receptacle combination to serve as the disconnecting means only when it is accessible. If it is not accessible — as with a plug hidden behind a fixed, fastened panel — the appliance must instead be provided with disconnecting means under 422.31. Upsizing the receptacle rating or assuming any factory plug automatically qualifies misses the accessibility requirement.

Correct: B — 422.31(B)

422.31(B) governs permanently connected appliances rated over 300 volt-amperes, requiring the branch-circuit switch or breaker serving as the disconnect to be within sight or lockable per 110.25; 422.31(A) only covers appliances at or under 300 VA or 1/8 hp, and 422.31(C) applies only to motor-operated appliances over 1/8 hp requiring 430.109/430.110 compliance.

Correct: B — 422.60(B), because the marking must be visible or easily accessible after installation

422.60(B) requires the marking be located so it stays visible or easily accessible after installation. The scenario doesn't describe missing content on the nameplate (which would implicate 422.60(A)) — it describes a location/accessibility problem after install.

Correct: B — The marked rating, which the overcurrent device cannot exceed

422.11(A) is explicit: if a protective device rating is marked on the appliance, the branch-circuit overcurrent device rating shall not exceed that marked value. Ignoring the marking in favor of 240.4 alone, applying the 150% single-appliance formula, or picking the higher of two values all miss that the marked rating is a hard ceiling.

Correct: A — The service disconnecting means is permitted to serve as the other required disconnect

Per 422.34(C), in one-family dwellings the service disconnecting means is permitted to serve as the other disconnecting means alongside the unit switch. A unit switch alone is never sufficient by itself under 422.34 — the 'same floor' rule applies to multifamily dwellings under 422.34(A), not one-family dwellings, and there's no requirement here for a dedicated within-sight disconnect.

Correct: C — No, the fan must be supported independently or by a box/system listed for fan support

422.18(A) requires ceiling-suspended fans to be supported independently of an outlet box, or by a listed outlet box/system identified for fan support installed per 314.27(C), or a listed weight-supporting receptacle system per 314.27(E). A generic fixture-rated box, metal or not, does not meet this unless it is specifically listed for fan support. The rule does allow box mounting when the box system is properly listed, so 'never' is also wrong.

Correct: C — The cord is at least 6 ft long to reach a nearby general-use receptacle

422.16(B)(4) actually caps cord length at a maximum of 4 ft (and a minimum of 18 in.) — a 6 ft cord reaching a shared general-use receptacle fails both the length limit and the individual-circuit requirement. The individual branch circuit, accessibility, and physical-damage protection conditions are all genuine requirements of this section.

Correct: B — It must be a polarized or grounding type plug

422.40 requires a polarized or grounding attachment plug whenever the appliance has a line-connected single-pole switch, an Edison-base lampholder, or a 15- or 20-ampere receptacle. A nonpolarized 2-wire plug is only allowed as a narrow exception for listed double-insulated shavers, not general appliances with these features.

Correct: A — 48 amperes

422.11(F)(1) caps each subdivided load at 48 amperes, with the overcurrent device protecting it rated at not more than 60 amperes. The 120 A and 150 A figures belong to the separate commercial-cooking and water-heater exceptions in 422.11(F)(2) and (F)(3), not the general rule.

Correct: A — The power supply must be subdivided into two or more circuits, each protected at not over 50A

Per 422.11(B), once calculated demand for a household surface-heating appliance exceeds 60A, the supply must be subdivided into two or more circuits, each with overcurrent protection not exceeding 50A. A single 65A circuit isn't allowed regardless of how the demand was calculated, and this is a household appliance rule, not a switch to the commercial provisions in 422.11(D).

Correct: B — 422.47

422.47 specifically covers water heater temperature-limiting controls, requiring a trip-free manual-reset or replaceable-element device separate from the control thermostat. 422.44 governs cord-and-plug-connected immersion heaters and 422.41 covers appliances subject to immersion, neither of which addresses the water heater's dedicated high-limit control.

Correct: B — 422.31(B)

422.31(B) governs disconnecting means for permanently connected appliances rated over 300 VA. 422.31(A) applies only to appliances rated 300 VA or less (or 1/8 hp or less), and 422.33(C) covers cord-and-plug ratings, not permanently wired equipment.