CSLB Trade — Electrical (C-10) — All Questions

In a dwelling living room, general-purpose receptacles must be placed so that no point measured horizontally along the floor line of any wall space is farther than what distance from a receptacle?

• a.6 ft✓
• b.10 ft
• c.8 ft
• d.12 ft

Section 210.52(A) requires receptacles so no point along the wall line is more than 6 ft from an outlet, which effectively caps spacing at 12 ft. This lets any 6-ft appliance cord reach an outlet without an extension cord. 8, 10, and 12 ft each exceed the 6-ft reach the rule protects.2023 NEC §210.52(A)

For dwelling receptacle spacing under 210.52(A), any wall space that is how wide or wider is counted as usable wall space requiring a receptacle?

• a.4 ft
• b.1 ft
• c.18 in
• d.2 ft✓

Section 210.52(A)(2) defines wall space to include any space 2 ft or more in width, including corners. A wall segment at least 2 ft wide must be served by a receptacle. 1 ft and 18 in are below the threshold, and 4 ft is larger than the code minimum.2023 NEC §210.52(A)

Along a dwelling kitchen countertop, receptacles must be installed so that no point along the wall counter space is more than what distance, measured horizontally, from a receptacle?

• a.48 in
• b.24 in✓
• c.12 in
• d.36 in

Section 210.52(C)(1) requires countertop receptacles so no point along the wall counter line is more than 24 in from a receptacle, giving a 4-ft maximum spacing. 12 in is stricter than required; 36 and 48 in would leave points beyond the reach of a typical appliance cord.2023 NEC §210.52(C)(1)

A kitchen wall counter space is required to be served by a countertop receptacle when the counter is at least what width?

• a.6 in
• b.9 in
• c.12 in✓
• d.10 in

Section 210.52(C)(1) applies to wall counter spaces 12 in or wider. A counter narrower than 12 in is not required to have a dedicated countertop receptacle. 6, 9, and 10 in are all below the 12-in trigger.2023 NEC §210.52(C)(1)

What is the minimum number of 20-ampere small-appliance branch circuits required to serve the receptacle outlets in a dwelling kitchen, pantry, breakfast room, and dining room?

• a.4
• b.1
• c.2✓
• d.3

Section 210.11(C)(1) requires at least two 20-A small-appliance branch circuits for these areas. These circuits serve countertop and receptacle outlets and cannot supply lighting. One circuit is insufficient; three or four exceed the code minimum.2023 NEC §210.11(C)(1)

The dwelling laundry receptacle outlet(s) required by 210.52(F) must be supplied by a branch circuit of at least what rating, dedicated to the laundry?

• a.30 A
• b.20 A✓
• c.15 A
• d.40 A

Section 210.11(C)(2) requires at least one additional 20-A branch circuit for the laundry receptacle(s), and it must have no other outlets. A 15-A circuit is too small; 30 and 40 A are not the required minimum for general laundry receptacles.2023 NEC §210.11(C)(2)

A dwelling bathroom receptacle outlet must be supplied by a branch circuit of at least what rating that serves only bathroom receptacle outlets?

• a.15 A
• b.30 A
• c.10 A
• d.20 A✓

Section 210.11(C)(3) requires at least one 20-A branch circuit to supply bathroom receptacle outlets. Where that circuit supplies only a single bathroom, it may also serve other equipment in that same bathroom. 10 and 15 A are below the required rating, and 30 A is not specified.2023 NEC §210.11(C)(3)

A 125-volt, 20-ampere receptacle installed in a dwelling bathroom must have what protection?

• a.GFCI✓
• b.AFCI only
• c.Surge protection
• d.No special protection

Section 210.8(A)(1) requires GFCI protection for all 125-V through 250-V receptacles in dwelling bathrooms because of the wet environment near sinks and tubs. AFCI addresses arc faults, not shock in wet locations; surge protection and 'none' do not meet the shock-protection requirement.2023 NEC §210.8(A)(1)

Under 210.8(A), a 125-volt receptacle located within how many feet of a dwelling laundry, utility, or wet bar sink (measured from the outside edge of the sink) requires GFCI protection?

• a.10 ft
• b.3 ft
• c.4 ft
• d.6 ft✓

Section 210.8(A)(7) requires GFCI protection for receptacles located within 6 ft of the outside edge of a sink. The distance is measured to the nearest edge of the sink. 3 and 4 ft are too short, and 10 ft is beyond the code radius.2023 NEC §210.8(A)

A 125-volt, 20-ampere receptacle installed in the unfinished portion of a dwelling basement used for storage or a work area requires what protection?

• a.GFCI✓
• b.AFCI only
• c.No protection
• d.Isolated ground

Section 210.8(A)(5) requires GFCI protection for receptacles in unfinished basement areas not intended as habitable rooms, such as storage and work areas, because of the damp concrete environment. AFCI alone does not provide shock protection; 'no protection' and an isolated ground do not satisfy the rule.2023 NEC §210.8(A)(5)

Receptacles installed in a dwelling attached garage at 125 volts, 20 amperes must be provided with what protection?

• a.None if dedicated
• b.GFCI✓
• c.AFCI only
• d.Surge protection

Section 210.8(A)(2) requires GFCI protection for all 125-V through 250-V receptacles in dwelling garages and accessory buildings. This includes receptacles for freezers or door openers. AFCI, surge protection, and a 'dedicated' exception do not remove the GFCI requirement.2023 NEC §210.8(A)(2)

Under 210.8(A), outdoor receptacles at a dwelling rated 125 volts, 20 amperes generally require what protection?

• a.Weatherproof cover only
• b.No protection
• c.GFCI✓
• d.AFCI

Section 210.8(A)(3) requires GFCI protection for receptacles installed outdoors at dwellings because of exposure to moisture. A weatherproof cover is also required by 406.9 but does not replace GFCI. AFCI and 'no protection' do not address outdoor shock hazards.2023 NEC §210.8(A)(3)

Under 210.8(A), a 125-volt, 20-ampere receptacle that serves a dwelling kitchen countertop surface requires what protection?

• a.Surge only
• b.None
• c.AFCI only
• d.GFCI✓

Section 210.8(A)(6) requires GFCI protection for receptacles serving dwelling kitchen countertop surfaces due to proximity to water. AFCI is separately required for the circuit but does not satisfy the GFCI rule; surge protection and 'none' do not protect against shock.2023 NEC §210.8(A)(6)

Which protection is required for 120-volt, 15- and 20-ampere branch circuits supplying receptacle outlets in dwelling bedrooms?

• a.None
• b.Surge only
• c.AFCI✓
• d.GFCI only

Section 210.12(A) requires arc-fault circuit-interrupter (AFCI) protection for 120-V, 15- and 20-A branch circuits supplying outlets in dwelling bedrooms and many other living areas. AFCI protects against arcing faults that can start fires. GFCI addresses shock, not arcing; surge and 'none' do not meet the rule.2023 NEC §210.12(A)

In a dwelling bathroom, at least one receptacle outlet must be installed within what distance of the outside edge of each basin?

• a.6 ft
• b.3 ft✓
• c.2 ft
• d.12 in

Section 210.52(D) requires a receptacle outlet within 3 ft of the outside edge of each bathroom basin. The receptacle must be on a wall or partition adjacent to the basin, or on the countertop/basin cabinet side. 12 in and 2 ft are stricter than required; 6 ft exceeds the code limit.2023 NEC §210.52(D)

For a one-family dwelling, how many outdoor receptacle outlets are required, and where?

• a.None
• b.One, at the front only
• c.At least one at the front and one at the back, accessible from grade✓
• d.One, in the garage

Section 210.52(E)(1) requires at least one receptacle outlet accessible from grade at both the front and back of a one-family dwelling, not more than 6.5 ft above grade. A single front outlet, a garage-only outlet, and 'none' all fail to meet the front-and-back requirement.2023 NEC §210.52(E)(1)

In a dwelling, a hallway of what length or more must have at least one receptacle outlet?

• a.20 ft
• b.6 ft
• c.15 ft
• d.10 ft✓

Section 210.52(H) requires at least one receptacle outlet in dwelling hallways 10 ft or more in length, measured along the centerline without passing through a doorway. Halls shorter than 10 ft are not required to have one; 15 and 20 ft are longer than the trigger.2023 NEC §210.52(H)

What is the minimum depth of working space in front of electrical equipment operating at 0 to 150 volts to ground, where there are exposed live parts on one side and no live or grounded parts on the other (Condition 1)?

• a.3.5 ft
• b.3 ft✓
• c.4 ft
• d.2.5 ft

Table 110.26(A)(1) requires a minimum working clearance of 3 ft (Condition 1) for equipment at 0-150 V to ground. This depth allows safe access for operation and maintenance. 2.5 ft is below the minimum; 3.5 and 4 ft apply to higher voltage or more hazardous conditions.2023 NEC §110.26(A)(1)

The width of the working space in front of electrical equipment must be at least the width of the equipment or what minimum, whichever is greater?

• a.28 in
• b.24 in
• c.36 in
• d.30 in✓

Section 110.26(A)(2) requires the working space width to be the width of the equipment or 30 in, whichever is greater. The space must also permit at least a 90-degree opening of equipment doors. 24 and 28 in are below the minimum; 36 in is more than required.2023 NEC §110.26(A)(2)

What is the minimum height (headroom) of the working space about electrical equipment such as panelboards, generally required by 110.26?

• a.6 ft
• b.6 ft 6 in✓
• c.6 ft 4 in
• d.6 ft 2 in

Section 110.26(A)(3) requires the working space to be clear and extend from the grade or floor to a height of 6.5 ft (6 ft 6 in) or the height of the equipment, whichever is greater. The lower heights listed do not satisfy the minimum headroom.2023 NEC §110.26(A)(3)

Electrical metallic tubing (EMT) must be securely fastened within what distance of each outlet box, junction box, or fitting?

• a.4 ft
• b.3 ft✓
• c.5 ft
• d.6 ft

Section 358.30(A) requires EMT to be securely fastened in place within 3 ft of each box, cabinet, or termination. It must also be supported at intervals not exceeding 10 ft. 4, 5, and 6 ft all exceed the 3-ft fastening distance from boxes.2023 NEC §358.30(A)

After the required fastening near boxes, EMT must be supported at intervals not exceeding what distance?

• a.6 ft
• b.8 ft
• c.10 ft✓
• d.12 ft

Section 358.30(A) requires EMT to be supported at least every 10 ft along the run. Combined with fastening within 3 ft of boxes, this keeps the raceway secure. 8 and 6 ft are stricter than required, and 12 ft exceeds the maximum support spacing.2023 NEC §358.30(A)

Between pull points (for example, from box to box), the total number of bends in one run of EMT must not exceed the equivalent of how many degrees?

• a.450
• b.180
• c.360✓
• d.270

Section 358.26 limits the total bends between pull points to the equivalent of four quarter bends, or 360 degrees. Exceeding this makes conductor pulling difficult and risks insulation damage. 180 and 270 are below the allowed total; 450 exceeds the code maximum.2023 NEC §358.26

Liquidtight flexible metal conduit (LFMC) must be securely fastened within what distance of each box, cabinet, or fitting where the conduit is not fished?

• a.18 in
• b.12 in✓
• c.3 ft
• d.2 ft

Section 350.30(A) requires LFMC to be fastened within 12 in of each box, cabinet, or termination and supported at intervals not exceeding 4.5 ft. The larger distances of 3 ft, 2 ft, and 18 in all exceed the 12-in fastening requirement for LFMC.2023 NEC §350.30(A)

Along its length, liquidtight flexible metal conduit (LFMC) must be supported at intervals not exceeding what distance?

• a.10 ft
• b.4.5 ft✓
• c.8 ft
• d.6 ft

Section 350.30(A) requires LFMC to be supported at intervals not exceeding 4.5 ft (1.4 m) along the run, in addition to fastening within 12 in of boxes. 6, 8, and 10 ft all exceed the maximum support spacing for this flexible raceway.2023 NEC §350.30(B)

Rigid metal conduit (RMC) must be securely fastened within what distance of each outlet box, junction box, or termination?

• a.5 ft
• b.3 ft✓
• c.2 ft
• d.6 ft

Section 344.30(A) requires RMC to be securely fastened within 3 ft of each box, cabinet, or fitting. Support intervals along the run then follow Table 344.30(B). 2 ft is stricter than the code minimum, while 5 and 6 ft exceed the required fastening distance.2023 NEC §344.30(A)

For 1/2-inch through 3/4-inch trade size rigid metal conduit (RMC), what is the maximum spacing between supports on a straight horizontal run per Table 344.30(B)?

• a.8 ft
• b.6 ft
• c.10 ft✓
• d.14 ft

Table 344.30(B) permits a maximum support spacing of 10 ft for 1/2-in and 3/4-in RMC. Larger conduit sizes allow greater spacing. 6 and 8 ft are stricter than needed; 14 ft applies only to larger trade sizes such as 2.5 in and above.2023 NEC §344.30(B)

For 1/2-inch through 1-inch trade size rigid PVC conduit, what is the maximum support spacing per Table 352.30?

• a.4 ft
• b.3 ft✓
• c.6 ft
• d.5 ft

Table 352.30 requires support of rigid PVC conduit sized 1/2 in through 1 in at intervals not exceeding 3 ft because PVC is more flexible than metal raceway. Larger sizes allow wider spacing. 5, 4, and 6 ft all exceed the 3-ft maximum for these small sizes.2023 NEC §352.30(B)

Expansion fittings for rigid PVC conduit must be provided to compensate for thermal expansion and contraction where the length change is expected to be at least how much?

• a.1 in
• b.2 in
• c.1/2 in
• d.1/4 in✓

Section 352.44 requires expansion fittings where the length change of PVC due to temperature is expected to be 1/4 in or greater. PVC expands and contracts significantly with temperature. 1/2 in, 1 in, and 2 in are all beyond the 1/4-in threshold that triggers the fitting.2023 NEC §352.44

Under Table 300.5, what is the minimum burial depth for a direct-buried rigid metal conduit (RMC) installed under a residential driveway of a one-family dwelling?

• a.6 in
• b.12 in
• c.18 in✓
• d.24 in

Table 300.5 requires 18 in minimum cover for RMC and IMC located under one- and two-family dwelling driveways. General non-driveway locations allow 6 in for RMC, but the driveway column increases this. 12 in and 6 in are too shallow here; 24 in is required for direct-buried cable, not RMC under a driveway.2023 NEC §300.5

Per Table 300.5, what is the minimum cover for direct-buried UF cable (without other protection) not under a driveway, in a residential branch circuit application?

• a.12 in
• b.36 in
• c.24 in✓
• d.6 in

Table 300.5 requires 24 in of cover for direct-buried cables and conductors in the general burial column. A GFCI-protected residential 120-V, 20-A branch circuit may be reduced to 12 in, but the base direct-burial requirement is 24 in. 6 in is far too shallow; 36 in is not required in this row.2023 NEC §300.5

Where cables or raceways are run parallel to framing members, the wiring must be kept at least what distance from the nearest edge of a wood stud where nails or screws are likely, unless protected by a steel plate?

• a.3/4 in
• b.1-1/8 in
• c.1-1/4 in✓
• d.1 in

Section 300.4(D) requires cables and raceways run parallel to framing to be at least 1-1/4 in from the nearest edge where nails or screws are likely; otherwise a 1/16-in steel plate is required. The smaller distances of 3/4, 1, and 1-1/8 in do not provide the required setback.2023 NEC §300.4(D)

Branch-circuit conductors must have an ampacity not less than the maximum load to be served and, before the application of adjustment or correction factors, not less than what portion of the continuous load?

• a.125 percent✓
• b.80 percent
• c.100 percent
• d.150 percent

Section 210.19(A) requires branch-circuit conductors to be sized at not less than 125 percent of the continuous load plus 100 percent of the noncontinuous load. This margin accounts for heat buildup under sustained load. 100 and 80 percent are too small; 150 percent is more than the code requires.2023 NEC §210.19(A)

A single receptacle installed on an individual branch circuit must have an ampere rating not less than what value relative to the branch circuit?

• a.No minimum applies
• b.125 percent of the circuit
• c.The rating of the branch circuit✓
• d.50 percent of the circuit

Section 210.21(B)(1) requires a single receptacle on an individual branch circuit to have an ampere rating not less than that of the branch circuit. A 20-A individual circuit therefore needs at least a 20-A receptacle. Half the circuit rating and 'no minimum' are wrong, and 125 percent is not required for the receptacle.2023 NEC §210.21(B)(1)

On a 20-ampere branch circuit supplying two or more receptacles, a single cord-and-plug-connected utilization equipment item must not have a rating exceeding what value?

• a.10 A
• b.16 A✓
• c.12 A
• d.20 A

Section 210.23(A)(1) limits any single cord-and-plug-connected utilization equipment to 80 percent of the branch-circuit rating where the circuit supplies two or more outlets. On a 20-A circuit that is 16 A. 10 and 12 A are stricter than required; 20 A would leave no margin and exceeds the 80-percent limit.2023 NEC §210.23(A)(1)

Each multiwire branch circuit must be provided with a means to simultaneously disconnect all what, at the point where the branch circuit originates?

• a.Ungrounded conductors✓
• b.Neutral conductors only
• c.Grounded conductors
• d.Equipment grounding conductors

Section 210.4(B) requires a means to simultaneously disconnect all ungrounded (hot) conductors of a multiwire branch circuit at the point of origin, typically a handle tie or common-trip breaker. This prevents shock when servicing a shared neutral. Grounded, equipment grounding, and neutral-only choices misstate the rule.2023 NEC §210.4(B)

In a dwelling unit, the voltage between conductors supplying lampholders, luminaires, and 15- and 20-ampere receptacles must not exceed what value?

• a.208 V
• b.277 V
• c.240 V
• d.120 V✓

Section 210.6(A) limits circuits supplying lampholders and standard 15- and 20-A receptacles in dwellings to 120 V between conductors. Higher voltages such as 208, 240, and 277 V are permitted only for specific equipment and larger circuits, not general dwelling lighting and receptacle circuits.2023 NEC §210.6(A)

Under the 2023 NEC, how may a receptacle be installed to serve a kitchen countertop or work surface?

• a.Up to 12 inches below the countertop, if the overhang is 6 inches or less
• b.Face-up in the countertop surface, as long as it is within 6 inches of the edge
• c.In the wall cabinet above the counter, within 30 inches of the surface
• d.On or above the countertop, not more than 20 inches above it (face-up only if listed for countertop use)✓

2023 NEC 210.52(C)(3) requires kitchen countertop receptacles to be on or above the counter, not more than 20 in (500 mm) above it; a face-up receptacle in the surface is allowed only if listed for countertop/work-surface use. Below-counter mounting (formerly permitted up to 12 in below) was removed in the 2020 NEC, and there is no allowance for face-up within 6 in of the edge or placement in the upper cabinet.2023 NEC §210.52(C)(3)

A receptacle outlet serving a dwelling countertop must be located not more than what distance above the countertop surface?

• a.20 in✓
• b.18 in
• c.12 in
• d.24 in

Section 210.52(C)(5) requires countertop receptacle outlets to be located not more than 20 in above the countertop. This keeps the receptacle within reach of countertop appliances. 12 and 18 in are stricter than required; 24 in exceeds the code maximum height.2023 NEC §210.52(C)(3)

In a dwelling, at least one wall switch-controlled lighting outlet must be installed in which of the following?

• a.Every habitable room and bathroom✓
• b.Only bedrooms
• c.Only bathrooms
• d.Only the kitchen

Section 210.70(A)(1) requires at least one wall switch-controlled lighting outlet in every habitable room and bathroom of a dwelling. Limiting it to only the kitchen, only bedrooms, or only bathrooms would leave other required rooms without switched lighting.2023 NEC §210.70(A)(1)

For equipment rated 1200 amperes or more and over 6 ft wide containing overcurrent devices, how many entrances of adequate size are required to give access to the working space?

• a.None required
• b.One total
• c.One at each end (two total)✓
• d.Three total

Section 110.26(C)(2) requires one entrance not less than 24 in wide and 6.5 ft high at each end of the working space for equipment rated 1200 A or more and over 6 ft wide, giving two entrances. A single entrance may be allowed only under specific exceptions. Three and 'none' are incorrect.2023 NEC §110.26(C)(2)

The dedicated equipment space above a panelboard indoors extends from the top of the equipment to what height, or to the structural ceiling if lower?

• a.6 ft✓
• b.4 ft
• c.3 ft
• d.10 ft

Section 110.26(E)(1)(a) requires the dedicated space above indoor electrical equipment such as panelboards to extend 6 ft above the equipment or to the structural ceiling, whichever is lower, kept clear of foreign piping and ducts. 3 and 4 ft are too little; 10 ft is more than the code requires.2023 NEC §110.26(E)

At each conductor splice point, outlet, switch point, or junction in a raceway or cable system, what must generally be installed?

• a.A box or conduit body✓
• b.An expansion fitting
• c.A bushing
• d.A grounding clamp

Section 300.15 requires a box or conduit body at each splice, outlet, switch, junction, or pull point in raceway and cable systems, providing access and enclosure for connections. A grounding clamp, expansion fitting, and bushing serve other purposes and do not satisfy this enclosure requirement.2023 NEC §300.15

Raceways, cable assemblies, boxes, and fittings must be securely fastened in place. Support wires that do not provide secure support are permitted only if what condition is met?

• a.They are at least 12 gauge
• b.They are painted
• c.They are copper
• d.An independent means of secure support is provided✓

Section 300.11(A) requires electrical wiring to be securely fastened and prohibits using ceiling-support wires unless an independent means of secure support is provided. The color, metal type, or gauge of a wire does not by itself satisfy the secure-support requirement.2023 NEC §300.11(A)

When counting conductors for box fill in a device box, each 14 AWG current-carrying conductor that originates outside the box and terminates or is spliced within it counts as how many conductors?

• a.One-half
• b.Two
• c.One✓
• d.Zero

Section 314.16(B)(1) counts each conductor that runs through the box or terminates in it as one conductor for box-fill volume. A 14 AWG conductor entering and terminating counts as one at 2.0 cubic inches. Counting it as two, one-half, or zero would misapply the box-fill calculation.2023 NEC §314.16

A 125-volt receptacle located within 6 ft of the outside edge of a bathtub or shower stall in a dwelling requires what protection?

• a.GFCI✓
• b.No protection
• c.AFCI only
• d.Surge only

Section 210.8(A)(9) requires GFCI protection for receptacles located within 6 ft of the outside edge of a bathtub or shower stall because of the wet environment. AFCI alone protects against arcing, not shock; 'no protection' and surge-only do not meet the requirement.2023 NEC §210.8(A)(9)

Under 210.8(F), outdoor outlets for dwellings supplying equipment such as air-conditioning condensers, rated 150 volts or less to ground and 60 amperes or less, generally require what?

• a.Surge protection
• b.GFCI protection✓
• c.No protection
• d.AFCI protection

Section 210.8(F) requires GFCI protection for outdoor outlets that supply dwelling equipment rated 150 V or less to ground and 60 A or less, including many HVAC condenser units. AFCI and surge protection do not address the outdoor shock hazard, and 'no protection' does not meet the rule.2023 NEC §210.8(F)

In an attached dwelling garage with two vehicle bays, at least how many receptacle outlets are required, and in what location?

• a.At least one in each vehicle bay✓
• b.One near the door only
• c.None
• d.One total, any wall

Section 210.52(G)(1) requires at least one receptacle outlet installed in each vehicle bay of a dwelling garage, not more than 5.5 ft above the floor. A two-bay garage therefore needs at least two. 'One total,' 'one near the door,' and 'none' do not satisfy the per-bay requirement.2023 NEC §210.52(G)(1)

A dwelling attached garage requires at least one branch circuit of what rating to supply the required garage receptacle outlets?

• a.120-volt, 20-ampere✓
• b.120-volt, 40-ampere
• c.240-volt, 30-ampere
• d.120-volt, 15-ampere

Section 210.11(C)(4) requires at least one 120-V, 20-A branch circuit to supply the receptacle outlets required in an attached garage, and it generally must not serve outlets outside the garage. A 15-A circuit is too small, and the 30-A and 40-A options are not the specified minimum.2023 NEC §210.11(C)(4)

A 125-volt, 15- or 20-ampere receptacle outlet for servicing must be installed within what distance of heating, air-conditioning, and refrigeration equipment?

• a.25 ft✓
• b.10 ft
• c.15 ft
• d.50 ft

Section 210.63 requires a 125-V, single-phase, 15- or 20-A receptacle within 25 ft of HVAC and refrigeration equipment, and on the same level, for servicing. 15 and 10 ft are stricter than required; 50 ft exceeds the maximum distance the code allows for the service receptacle.2023 NEC §210.63