CSLB General Building (B) — 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.8 ft
• c.10 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.1 ft
• b.18 in
• c.2 ft✓
• d.4 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.12 in
• b.24 in✓
• c.36 in
• d.48 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.10 in
• d.12 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.2✓
• b.1
• c.3
• d.4

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.15 A
• b.20 A✓
• c.30 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.10 A
• b.15 A
• c.20 A✓
• d.30 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.AFCI only
• b.Surge protection
• c.No special protection
• d.GFCI✓

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.6 ft✓
• b.3 ft
• c.10 ft
• d.4 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.AFCI only
• b.GFCI✓
• 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.AFCI only
• b.Surge protection
• c.GFCI✓
• d.None if dedicated

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

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

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

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.12 in
• b.2 ft
• c.3 ft✓
• d.6 ft

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

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.10 ft✓
• b.6 ft
• c.15 ft
• d.20 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.2.5 ft
• b.3 ft✓
• c.3.5 ft
• d.4 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.24 in
• b.28 in
• c.30 in✓
• d.36 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 2 in
• c.6 ft 4 in
• d.6 ft 6 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.3 ft✓
• b.4 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.8 ft
• b.10 ft✓
• c.12 ft
• d.6 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.180
• b.270
• c.360✓
• d.450

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.3 ft
• b.2 ft
• c.18 in
• d.12 in✓

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.4.5 ft✓
• b.6 ft
• c.8 ft
• d.10 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.2 ft
• b.3 ft✓
• c.5 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.6 ft
• b.8 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.5 ft
• b.4 ft
• c.6 ft
• d.3 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.1/4 in✓
• b.1/2 in
• c.1 in
• d.2 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.12 in
• b.18 in✓
• c.24 in
• d.6 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.6 in
• b.12 in
• c.24 in✓
• d.36 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 in
• c.1-1/8 in
• d.1-1/4 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.100 percent
• c.80 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.50 percent of the circuit
• b.The rating of the branch circuit✓
• c.125 percent of the circuit
• d.No minimum applies

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.12 A
• c.16 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.Grounded conductors
• b.Equipment grounding conductors
• c.Neutral conductors only
• d.Ungrounded 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.120 V✓
• b.208 V
• c.240 V
• d.277 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.Face-up in the countertop surface, as long as it is within 6 inches of the edge
• b.Up to 12 inches below the countertop, if the overhang is 6 inches or less
• c.On or above the countertop, not more than 20 inches above it (face-up only if listed for countertop use)✓
• d.In the wall cabinet above the counter, within 30 inches of the surface

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.12 in
• b.18 in
• c.20 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.Only the kitchen
• b.Only bedrooms
• c.Only bathrooms
• d.Every habitable room and bathroom✓

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

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.3 ft
• b.6 ft✓
• c.4 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 grounding clamp
• b.An expansion fitting
• c.A box or conduit body✓
• d.A bushing

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 painted
• b.They are copper
• c.They are at least 12 gauge
• 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✓
• b.Two
• c.One-half
• 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.AFCI only
• b.GFCI✓
• c.No protection
• 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.AFCI protection
• b.Surge protection
• c.GFCI protection✓
• d.No 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.One total, any wall
• b.One near the door only
• c.None
• d.At least one in each vehicle bay✓

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, 15-ampere
• c.240-volt, 30-ampere
• d.120-volt, 40-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.15 ft
• b.25 ft✓
• c.50 ft
• d.10 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

Bends in electrical metallic tubing (EMT) must be made so that which of the following is true?

• a.At least six bends are used
• b.The tubing is heated first
• c.The tubing is not damaged and its internal diameter is not effectively reduced✓
• d.The radius is as tight as possible

Section 358.24 requires EMT bends to be made so the tubing is not damaged and the internal diameter is not effectively reduced, using at least the radius shown in Chapter 9, Table 2. Kinking or flattening the tubing violates this. Heating EMT, forcing the tightest radius, or a fixed number of bends are not the standard.2023 NEC §358.24

Direct-buried conductors or cables emerging from grade must be protected by enclosures or raceways from the required cover depth up to what height above finished grade?

• a.3 ft
• b.5 ft
• c.6 ft
• d.8 ft✓

Section 300.5(D)(1) requires direct-buried conductors and cables emerging from grade to be protected by enclosures or raceways from the required burial depth to at least 8 ft above finished grade. Lower heights of 3, 5, and 6 ft leave the emerging conductors exposed to physical damage.2023 NEC §300.5(D)(1)

Rigid polyvinyl chloride conduit (PVC) is permitted to be used in which of the following locations?

• a.Wet locations and direct burial where listed✓
• b.Only in dry indoor locations
• c.Only where exposed to sunlight
• d.Only inside metal enclosures

Section 352.10 permits rigid PVC conduit in wet locations, corrosive environments, concealed work, and direct burial where properly listed and assembled. Restricting it to dry indoor use, sunlight-only, or inside metal enclosures misstates its permitted uses. PVC is widely used underground for branch-circuit feeders.2023 NEC §352.10

Electrical metallic tubing (EMT) is generally not permitted to be used in which condition?

• a.Concealed in walls
• b.Where subject to severe physical damage✓
• c.In dry indoor locations
• d.Exposed on masonry

Section 358.12 prohibits EMT where subject to severe physical damage. EMT is permitted concealed in walls, in dry locations, and exposed on masonry when properly supported and protected. Only the severe-physical-damage condition is a listed prohibition among these choices.2023 NEC §358.12

Liquidtight flexible metal conduit (LFMC) is especially suited for which of the following uses?

• a.As a general lighting raceway in dry ceilings only
• b.Only for service-entrance conductors
• c.Connections to equipment where flexibility and protection from liquids are needed✓
• d.Only for direct burial without fittings

Section 350.10 permits LFMC where flexibility or protection from liquids, vapors, or solids is required, such as connections to motors and outdoor equipment. It is not limited to dry ceilings, is not intended specifically for service-entrance conductors, and requires listed fittings rather than bare direct burial.2023 NEC §350.10

Rigid metal conduit (RMC) is permitted to be used under which of the following conditions?

• a.Only in dry locations
• b.Only where concealed
• c.Only in dwellings
• d.In all atmospheric conditions and occupancies✓

Section 344.10 permits RMC in all atmospheric conditions and occupancies, with appropriate corrosion protection where needed. It is one of the most robust raceways. Limiting it to dry, concealed, or dwelling-only uses understates the broad permission the code grants RMC.2023 NEC §344.10

Cables or raceways installed under metal-corrugated sheet roof decking must be kept at least what distance from the lowest surface of the roof decking to the top of the raceway or cable?

• a.1-1/2 in✓
• b.3/4 in
• c.1 in
• d.2 in

Section 300.4(E) requires cables and raceways under metal-corrugated sheet roof decking to be kept at least 1-1/2 in from the lowest surface of the decking, protecting the wiring from roofing screws. The smaller 3/4-in and 1-in distances are insufficient, and 2 in is more than the code minimum.2023 NEC §300.4(E)

What is the minimum working-space depth for electrical equipment operating at 151 to 600 volts to ground under Condition 2 (exposed live parts on one side and grounded parts on the other)?

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

Table 110.26(A)(1) requires 3.5 ft of working clearance for 151-600 V to ground under Condition 2. Condition 1 at that voltage is 3 ft and Condition 3 is 4 ft. 2.5 ft is below any required minimum in this range.2023 NEC §110.26(A)(1)

In a commercial (other than dwelling) building, a 125-volt, 20-ampere receptacle installed in a bathroom must have what protection?

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

Section 210.8(B) requires GFCI protection for 125-V through 250-V receptacles in non-dwelling bathrooms, kitchens, rooftops, and similar locations. AFCI is not the specified requirement here; 'no protection' and surge-only leave the shock hazard unaddressed.2023 NEC §210.8(B)

Under 240.4(D), what is the maximum overcurrent protection permitted for a 14 AWG copper branch-circuit conductor, absent a specific exception?

• a.30 A
• b.25 A
• c.20 A
• d.15 A✓

Section 240.4(D)(3) limits 14 AWG copper conductors to a maximum overcurrent device of 15 A. This is why 14 AWG is used on 15-A branch circuits. 20, 25, and 30 A all exceed the small-conductor protection limit for 14 AWG copper.2023 NEC §240.4(D)

Under 240.4(D), what is the maximum overcurrent protection permitted for a 12 AWG copper branch-circuit conductor, absent a specific exception?

• a.20 A✓
• b.25 A
• c.30 A
• d.40 A

Section 240.4(D)(5) limits 12 AWG copper conductors to a maximum overcurrent device of 20 A, which is why 12 AWG is standard for 20-A branch circuits. 25, 30, and 40 A all exceed the small-conductor protection limit for 12 AWG copper.2023 NEC §240.4(D)

The rating of a branch circuit supplying two or more outlets is determined by what?

• a.The largest conductor
• b.The ampere rating of the overcurrent device protecting the circuit✓
• c.The receptacle count
• d.The voltage only

Section 210.3 states that a branch circuit's rating is determined by the maximum permitted ampere rating of the overcurrent device protecting the circuit, using standard sizes such as 15, 20, 30, 40, and 50 A. The conductor size, number of receptacles, or voltage alone do not define the branch-circuit rating.2023 NEC §210.18

The working space required in front of electrical equipment must be kept clear and, in general, may be used for what purpose?

• a.Storage of conduit
• b.Temporary parts staging
• c.No storage; it must remain clear for access✓
• d.Mounting a subpanel

Section 110.26(B) requires the working space to be kept clear and prohibits using it for storage; when energized equipment needs servicing, the space must be clear. Using it for conduit storage, parts staging, or mounting another panel would obstruct required access to live parts.2023 NEC §110.26(B)

Couplings and connectors used with electrical metallic tubing (EMT) in a wet location must be what?

• a.Threaded
• b.Set-screw type
• c.Painted
• d.Listed for use in wet locations✓

Section 358.42 requires EMT couplings and connectors used in wet locations to be listed for wet locations, commonly the raintight compression type. Plain set-screw fittings are not raintight, threading does not apply to EMT couplings, and paint does not make a fitting suitable for wet locations.2023 NEC §358.42

An outlet box used as the sole support for a ceiling-suspended (paddle) fan must be what?

• a.Listed and marked for that purpose✓
• b.Any 4-inch square box
• c.A plastic device box
• d.A handy box

Section 314.27(C) requires an outlet box used as the sole support of a ceiling-suspended paddle fan to be listed and marked for that application, and to support the fan weight. A standard 4-in square box, a plastic device box, or a handy box not so listed cannot serve as the sole fan support.2023 NEC §314.27(C)

A 4" x 1-1/2" square box has a volume of 21.0 in³. With no clamps, devices, or other allowances, what is the maximum number of 14 AWG conductors permitted in the box?

• a.10✓
• b.9
• c.11
• d.8

Each 14 AWG conductor requires a 2.00 in³ volume allowance from Table 314.16(B). 21.0 ÷ 2.00 = 10.5, and you round down to 10 conductors. Rounding up to 11 would exceed the box volume, and 9 or 8 understates the count.2023 NEC §314.16(B)

Using the same 21.0 in³ box with no other fill allowances, what is the maximum number of 12 AWG conductors permitted?

• a.10
• b.9✓
• c.8
• d.7

Each 12 AWG conductor requires 2.25 in³ per Table 314.16(B). 21.0 ÷ 2.25 = 9.33, rounded down to 9 conductors. 10 would exceed the volume, and 8 or 7 undercounts.2023 NEC §314.16(B)

Per Table 314.16(B), what is the free-space volume allowance required for a single 12 AWG conductor?

• a.2.00 in³
• b.2.50 in³
• c.2.25 in³✓
• d.3.00 in³

Table 314.16(B) assigns 2.25 in³ per 12 AWG conductor. 2.00 in³ is the value for 14 AWG, 2.50 in³ is for 10 AWG, and 3.00 in³ is for 8 AWG.2023 NEC §314.16(B)

In a box-fill calculation, a single device (a receptacle or switch mounted on a yoke or strap) counts as how many conductor volume allowances?

• a.1
• b.0
• c.3
• d.2✓

Per 314.16(B)(4), each yoke or strap containing one or more devices counts as two volume allowances, based on the largest conductor connected to the device. Counting it as 1 or 0 understates the fill; a standard single device is not 3.2023 NEC §314.16(B)(4)

A box contains three internal cable clamps. In the box-fill calculation, how many volume allowances do the clamps require in total?

• a.1 (a single allowance)✓
• b.3 (one per clamp)
• c.0 (clamps are exempt)
• d.6 (two per clamp)

Per 314.16(B)(2), where one or more internal clamps are present, a single volume allowance is required based on the largest conductor in the box — not one per clamp. So three clamps still count as only one allowance.2023 NEC §314.16(B)(2)

A box has four 12 AWG equipment grounding conductors entering it. How are they counted in the box-fill calculation?

• a.Each counts individually (four allowances)
• b.All together count as a single volume allowance✓
• c.They are never counted
• d.They count as two allowances

Per 314.16(B)(5), all equipment grounding conductors together count as a single volume allowance, based on the largest EGC present. Counting them individually overstates the fill, and they are not exempt from the calculation.2023 NEC §314.16(B)(5)

A box contains five 12 AWG current-carrying conductors, one 12 AWG equipment grounding conductor, one internal cable clamp, and one switch on a yoke (all conductors 12 AWG). What total box volume is required?

• a.18.00 in³
• b.15.75 in³
• c.20.25 in³✓
• d.22.50 in³

At 2.25 in³ each: five conductors = 11.25, EGCs (as one) = 2.25, clamp (as one) = 2.25, and the yoke = 2 × 2.25 = 4.50. Total = 11.25 + 2.25 + 2.25 + 4.50 = 20.25 in³. The other values omit one or more required allowances.2023 NEC §314.16(B)

A single unbroken conductor passes straight through a box without being spliced or terminated. For box fill, it is counted as how many conductors?

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

Per 314.16(B)(1), each conductor that runs through the box without splice or termination is counted once. It is not exempt (zero) and not doubled; a conductor is only counted twice when it is looped unbroken with a length of at least twice the minimum required for free conductors.2023 NEC §314.16(B)(1)

How are conductors that both originate and terminate within the box (such as short pigtails or jumpers) treated in a box-fill calculation?

• a.They are not counted✓
• b.They count as one each
• c.They count as two each
• d.They count as clamp allowances

Per 314.16(B)(1), a conductor that originates and terminates within the box, such as a pigtail, is not counted in the box fill. Only conductors that enter and are not spliced (or that terminate on a device) get an allowance.2023 NEC §314.16(B)(1)

Per Chapter 9, Table 1, what is the maximum permitted conduit fill percentage when three or more conductors are installed in a raceway?

• a.31%
• b.40%✓
• c.53%
• d.60%

Chapter 9, Table 1 limits fill to 40% for three or more conductors. 53% is the limit for a single conductor, 31% is for exactly two conductors, and 60% is not a code fill value.2023 NEC Chapter 9, Table 1

Per Chapter 9, Table 1, what is the maximum permitted fill percentage when exactly two conductors are installed in a conduit?

• a.40%
• b.53%
• c.31%✓
• d.25%

Table 1 sets a 31% fill limit for exactly two conductors, reflecting the jamming ratio concern. 40% applies to three or more, 53% to a single conductor, and 25% is not used.2023 NEC Chapter 9, Table 1

Per Chapter 9, Table 1, what is the maximum permitted fill percentage when only one conductor is installed in a conduit?

• a.31%
• b.40%
• c.60%
• d.53%✓

A single conductor may fill up to 53% of the conduit's internal area per Table 1. 31% is for two conductors, 40% for three or more, and 60% is not a code value.2023 NEC Chapter 9, Table 1

Per Annex C, Table C.1, what is the maximum number of 12 AWG THHN conductors permitted in 1/2" EMT?

• a.9✓
• b.12
• c.7
• d.5

Table C.1 lists 9 for 12 AWG THHN in 1/2" EMT. 12 is the count for 14 AWG, 5 is for 10 AWG, and 7 is not a listed value.2023 NEC Annex C, Table C.1

Per Annex C, Table C.1, what is the maximum number of 14 AWG THHN conductors permitted in 1/2" EMT?

• a.9
• b.12✓
• c.10
• d.15

Table C.1 lists 12 for 14 AWG THHN in 1/2" EMT. 9 is the count for 12 AWG, and 10 or 15 are not listed values for this size.2023 NEC Annex C, Table C.1

Per Annex C, Table C.1, what is the maximum number of 12 AWG THHN conductors permitted in 3/4" EMT?

• a.9
• b.22
• c.16✓
• d.12

Table C.1 lists 16 for 12 AWG THHN in 3/4" EMT. 22 is the count for 14 AWG in 3/4" EMT, and 9 is the count for 12 AWG in the smaller 1/2" EMT.2023 NEC Annex C, Table C.1

Per Annex C, Table C.1, what is the maximum number of 10 AWG THHN conductors permitted in 1/2" EMT?

• a.9
• b.7
• c.3
• d.5✓

Table C.1 lists 5 for 10 AWG THHN in 1/2" EMT. 9 is the value for 12 AWG, 3 is the value for 8 AWG, and 7 is not listed for this size.2023 NEC Annex C, Table C.1

The internal cross-sectional area of 1/2" EMT is 0.304 in³ per Table 4. For three or more conductors, what usable fill area (40%) is available?

• a.0.122 in²✓
• b.0.094 in²
• c.0.161 in²
• d.0.304 in²

0.304 × 0.40 = 0.122 in². The 31% (two-conductor) area would be 0.094 in² and the 53% (single-conductor) area would be 0.161 in²; 0.304 is the full 100% area.2023 NEC Chapter 9, Table 4

The internal area of 3/4" EMT is 0.533 in² per Table 4. What is the 40% usable fill area for three or more conductors?

• a.0.165 in²
• b.0.213 in²✓
• c.0.283 in²
• d.0.122 in²

0.533 × 0.40 = 0.213 in². The 31% area is 0.165 in² and the 53% area is 0.283 in²; 0.122 in² is the 40% area of the smaller 1/2" EMT.2023 NEC Chapter 9, Table 4

Given a 40% usable fill area of 0.213 in² (3/4" EMT) and a 12 AWG THHN cross-sectional area of 0.0133 in² (Table 5), how many 12 AWG THHN conductors fit?

• a.9
• b.12
• c.16✓
• d.22

0.213 ÷ 0.0133 = 16.0, so 16 conductors fit — matching Annex C. 9 corresponds to 1/2" EMT, 22 is the 14 AWG count for 3/4", and 12 is not correct here.2023 NEC Chapter 9, Table 4

Six current-carrying 12 AWG THHN conductors (90°C, 30 A base) share a raceway. Applying only the adjustment factor for 4–6 conductors, what is the adjusted ampacity?

• a.30 A
• b.21 A
• c.27 A
• d.24 A✓

The adjustment factor for 4–6 current-carrying conductors is 80%. 30 A × 0.80 = 24 A. 70% (21 A) applies to 7–9 conductors, and 30 A ignores the required adjustment.2023 NEC §310.15(C)(1)

Per Table 310.15(C)(1), what adjustment (derating) factor applies when there are 7 to 9 current-carrying conductors in a raceway?

• a.70%✓
• b.80%
• c.50%
• d.60%

The table assigns 70% for 7–9 current-carrying conductors. 80% is for 4–6, 50% is for 10–20, and 60% is not a listed factor.2023 NEC §310.15(C)(1)

Per Table 310.15(C)(1), what adjustment factor applies when there are 4 to 6 current-carrying conductors in a raceway?

• a.70%
• b.80%✓
• c.60%
• d.50%

The table assigns 80% for 4–6 current-carrying conductors. 70% is for 7–9, 50% is for 10–20, and 60% is not a listed factor.2023 NEC §310.15(C)(1)

Per Table 310.15(C)(1), what adjustment factor applies when there are 10 to 20 current-carrying conductors in a raceway?

• a.70%
• b.80%
• c.50%✓
• d.45%

The table assigns 50% for 10–20 current-carrying conductors. 80% is for 4–6, 70% is for 7–9, and 45% is for 21–30 conductors.2023 NEC §310.15(C)(1)

In a 3-wire, single-phase circuit (two hots and a neutral), how is the neutral treated when counting current-carrying conductors for adjustment?

• a.Always counted as current-carrying
• b.Counted only if it is 12 AWG
• c.Counted as one-half a conductor
• d.Not counted, since it carries only unbalanced current✓

Per 310.15(E), the neutral of a 3-wire single-phase circuit carries only the unbalanced current and is not counted as a current-carrying conductor. It would be counted only in a 4-wire wye supplying significant nonlinear (harmonic) load.2023 NEC §310.15(E)

In a 4-wire, 3-phase wye circuit supplying nonlinear (harmonic-producing) loads, how is the neutral treated for conductor-count adjustment?

• a.It is counted as a current-carrying conductor✓
• b.It is never counted
• c.It is counted as one-half
• d.It counts only if it is bare

Per 310.15(E), where the major portion of the load is nonlinear, harmonic currents load the neutral, so it must be counted as a current-carrying conductor. This differs from a balanced wye neutral, which normally is not counted.2023 NEC §310.15(E)

Is an equipment grounding conductor (EGC) ever counted as a current-carrying conductor when applying conductor-count adjustment factors?

• a.Yes, always
• b.No, it is never counted✓
• c.Only when it is 12 AWG
• d.Only when it is bare

Per 310.15(E), a grounding or bonding conductor is not counted as a current-carrying conductor because it carries current only under fault conditions. Its size and whether it is bare do not change this.2023 NEC §310.15(E)

An 8 AWG THHN copper conductor (55 A at the 90°C column) is installed where the ambient temperature is 46–50°C. Using the 90°C correction factor of 0.82, what is the corrected ampacity?

• a.55 A
• b.50 A
• c.45 A✓
• d.41 A

55 A × 0.82 = 45.1 A, rounded to 45 A. Using no correction (55 A) ignores the elevated ambient, and the other values apply the wrong factor.2023 NEC §310.15(B)

Six current-carrying 10 AWG THHN copper conductors (40 A at 90°C) run in a raceway at 40°C ambient. Applying the 0.91 ambient correction and the 0.80 conductor-count adjustment, what is the resulting ampacity?

• a.40 A
• b.35 A
• c.32 A
• d.29 A✓

40 A × 0.91 × 0.80 = 29.1 A, or about 29 A. Both factors must be applied from the 90°C base; using only one factor overstates the result.2023 NEC §310.15

For a branch circuit rated 100 A or less, which temperature column must be used for conductor ampacity at the terminations unless the equipment or terminals are listed for a higher temperature?

• a.60°C✓
• b.75°C
• c.90°C
• d.Any column may be used

Per 110.14(C)(1), for circuits 100 A or less the 60°C column applies unless the equipment/terminals are listed for 75°C (or higher). The 90°C column is never the termination limit, and you cannot freely choose the column.2023 NEC §110.14(C)

A 90°C-rated conductor is terminated on equipment whose lugs are listed for 75°C. Which temperature column limits the conductor's final ampacity at that termination?

• a.90°C
• b.75°C✓
• c.60°C
• d.55°C

Per 110.14(C), the final ampacity cannot exceed the lowest-rated termination — here 75°C. The 90°C rating may be used only for derating math, and 60°C would apply only if the terminals were rated for 60°C.2023 NEC §110.14(C)

Under what circumstance may the 90°C ampacity column of Table 310.16 be used?

• a.For final conductor sizing at the terminals
• b.For the branch-circuit load calculation
• c.Only for applying adjustment and correction (derating) factors✓
• d.It may never be used

The 90°C column serves only as the starting point for adjustment and correction factors, provided the conductor is 90°C rated. The final ampacity is still limited by the termination temperature per 110.14(C), so it cannot set the final size directly.2023 NEC §110.14(C)

Per Table 310.16, what is the ampacity of an 8 AWG copper THHN conductor in the 90°C column?

• a.40 A
• b.50 A
• c.45 A
• d.55 A✓

Table 310.16 lists 55 A for 8 AWG copper at 90°C. 40 A is the 60°C value and 50 A is the 75°C value for 8 AWG copper; 45 A is not a listed value for this size.2023 NEC §310.16

Per Table 310.16, what is the ampacity of a 12 AWG copper conductor in the 75°C column (before any small-conductor overcurrent limit)?

• a.25 A✓
• b.20 A
• c.30 A
• d.35 A

Table 310.16 lists 25 A for 12 AWG copper at 75°C. 20 A is the 60°C value (and also the 240.4(D) OCPD limit), while 30 A is the 90°C value; 35 A is for 10 AWG.2023 NEC §310.16

Per Table 310.16, what is the ampacity of a 10 AWG copper conductor in the 60°C column?

• a.35 A
• b.30 A✓
• c.40 A
• d.25 A

Table 310.16 lists 30 A for 10 AWG copper at 60°C. 35 A is the 75°C value and 40 A is the 90°C value for 10 AWG copper; 25 A is the 12 AWG (75°C) value.2023 NEC §310.16

Per Table 310.16, what is the ampacity of a 6 AWG copper conductor in the 75°C column?

• a.55 A
• b.75 A
• c.65 A✓
• d.85 A

Table 310.16 lists 65 A for 6 AWG copper at 75°C. 55 A is the 60°C value and 75 A is the 90°C value for 6 AWG copper; 85 A is the 75°C value for 4 AWG.2023 NEC §310.16

Per 334.80, the ampacity of Type NM (nonmetallic-sheathed) cable is based on which temperature column of Table 310.16?

• a.90°C
• b.75°C
• c.Any column, at the installer's choice
• d.60°C✓

Section 334.80 requires NM cable ampacity to be taken from the 60°C column, even though the conductors themselves are 90°C rated. The 90°C rating may be used only for derating calculations, not as the base ampacity.2023 NEC §334.80

For Type NM cable, the 90°C rating of its conductors may be used for what purpose?

• a.Only for adjustment and correction (derating) calculations✓
• b.For establishing the final ampacity
• c.It may not be used at all
• d.For the load calculation

Per 334.80, the 90°C column may be used as the starting point when applying ambient and conductor-count factors, but the final NM ampacity is still governed by the 60°C column. It cannot set the final ampacity directly.2023 NEC §334.80

A 12-2 Type NM cable (two 12 AWG conductors plus ground) is used for a general branch circuit. Using the required NM temperature column, what is the ampacity of its 12 AWG conductors?

• a.25 A
• b.20 A✓
• c.30 A
• d.15 A

NM ampacity uses the 60°C column, where 12 AWG copper is 20 A. 25 A is the 75°C value and 30 A is the 90°C value, neither of which applies as the base for NM; 15 A is the 14 AWG (60°C) value.2023 NEC §334.80

Per 334.30, Type NM cable must be secured and supported at intervals not exceeding what distance along the run?

• a.3 ft (900 mm)
• b.6 ft (1.8 m)
• c.4-1/2 ft (1.4 m)✓
• d.10 ft (3.0 m)

Section 334.30 requires NM cable to be secured at intervals not exceeding 4-1/2 ft, and within 12 in of every box or fitting. 6 ft is the MC interval, while 3 ft and 10 ft are not NM support values.2023 NEC §334.30

Per 334.12, which of the following installations is NOT permitted for Type NM cable?

• a.Dry interior stud wall of a dwelling
• b.Exposed in a dry, protected location
• c.Concealed in a dry attic
• d.Embedded in poured concrete✓

Section 334.12 prohibits NM cable from being embedded in poured concrete, aggregate, or plaster, and from wet or damp locations. Dry interior walls, dry attics, and protected exposed dry runs are all permitted uses under 334.10.2023 NEC §334.12

Per 330.30, Type MC cable must be supported and secured at intervals not exceeding what distance?

• a.6 ft (1.8 m)✓
• b.4-1/2 ft (1.4 m)
• c.3 ft (900 mm)
• d.10 ft (3.0 m)

Section 330.30 requires MC cable to be secured at intervals not exceeding 6 ft, and within 12 in of a box where practicable. 4-1/2 ft is the NM/AC interval; 3 ft and 10 ft are not MC support values.2023 NEC §330.30

Which statement about Type MC cable ampacity is correct?

• a.Like NM, MC ampacity is limited to the 60°C column
• b.MC ampacity may be based on the 75°C or 90°C rating of its conductors, subject to terminations✓
• c.MC is always limited to the 75°C column
• d.MC is always taken at the 90°C column regardless of terminations

Per 330.80, MC cable ampacity follows 310.15 based on the conductor temperature rating (commonly 90°C for derating), then limited by the termination temperature per 110.14(C). Unlike NM, it is not capped at 60°C, but it is also not simply taken at 90°C at the terminals.2023 NEC §330.80

Under what condition may Type MC cable be installed in a wet location?

• a.Never, MC is dry-location only
• b.Always, MC is unrestricted
• c.Only when it is listed and identified for wet locations with a suitable moisture-impervious jacket✓
• d.Only where installed underground

Per 330.10, MC cable may be used in wet locations only where the metallic covering is impervious to moisture (or a jacket is provided) and the cable is listed/identified for the use. It is not unrestricted, and wet-location use is not limited to underground runs.2023 NEC §330.10

Per 320.40, what must be installed at each termination of Type AC (armored) cable to protect the conductors from the cut edge of the metal armor?

• a.A grounding bushing
• b.A locknut
• c.A cable connector only
• d.An anti-short insulating bushing ("red head")✓

Section 320.40 requires an insulating anti-short bushing, commonly called a red head, at each armored-cable termination to protect the conductor insulation from the sharp armor. A locknut or connector alone does not protect against the cut armor edge, and a grounding bushing serves a different purpose.2023 NEC §320.40

Per 320.30, Type AC cable must be secured and supported at intervals not exceeding what distance?

• a.4-1/2 ft (1.4 m)✓
• b.6 ft (1.8 m)
• c.3 ft (900 mm)
• d.10 ft (3.0 m)

Section 320.30 requires AC cable to be secured at intervals not exceeding 4-1/2 ft, and within 12 in of every box or fitting. 6 ft is the MC interval; 3 ft and 10 ft are not AC support values.2023 NEC §320.30

Which cable relies on its metal armor together with an internal aluminum bonding strip to serve as the equipment grounding path?

• a.Type MC
• b.Type AC✓
• c.Type NM
• d.Type UF

Per 320.100, Type AC cable includes an internal bonding strip that, combined with the armor, forms an effective ground-fault return path. Type MC generally includes a separate equipment grounding conductor, while NM and UF use an insulated or bare EGC, not the armor.2023 NEC §320.100

The NEC informational note recommends that voltage drop on a branch circuit not exceed what percentage of the circuit voltage?

• a.5%
• b.2%
• c.3%✓
• d.10%

The informational note to 210.19(A) recommends a maximum 3% voltage drop on a branch circuit for reasonable efficiency. 5% is the combined feeder-plus-branch recommendation, and 2% or 10% are not the branch-circuit figure.2023 NEC §210.19(A), Informational Note

For the combined feeder plus branch circuit, the NEC informational note recommends total voltage drop not exceed what percentage?

• a.3%
• b.2%
• c.8%
• d.5%✓

The informational notes recommend not more than 3% on the feeder and not more than 5% combined for feeder plus branch. 3% alone is the branch-circuit figure, and 2% or 8% are not the recommended totals.2023 NEC §215.2(A)(1), Informational Note

A 120 V single-phase circuit uses 12 AWG copper (6,530 cmil) carrying 20 A over a one-way length of 100 ft. Using VD = 2 × K × I × L ÷ cmil with K = 12.9, what is the approximate voltage drop?

• a.7.9 V (about 6.6%)✓
• b.3.9 V (about 3.3%)
• c.2.0 V (about 1.7%)
• d.5.0 V (about 4.2%)

VD = 2 × 12.9 × 20 × 100 ÷ 6,530 = 51,600 ÷ 6,530 ≈ 7.9 V, which is 7.9/120 ≈ 6.6%. The lower values would require either a shorter run or a larger conductor.

The circuit in the previous scenario has a voltage drop of about 6.6%, well above the recommended 3% for a branch circuit. What is the most appropriate corrective action?

• a.Leave it; 6.6% is acceptable
• b.Increase the conductor size to reduce voltage drop✓
• c.Increase the breaker size to 30 A
• d.Add a second ground rod

Increasing the conductor cross-sectional area (more circular mils) lowers the voltage drop, since VD is inversely proportional to cmil. Raising the breaker size does not reduce voltage drop (and may violate conductor ampacity), and grounding changes do not affect voltage drop.

A 240 V single-phase circuit uses 10 AWG copper (10,380 cmil) carrying 24 A over a one-way length of 150 ft, with K = 12.9. What is the approximate voltage drop and percentage?

• a.4.5 V, about 1.9%
• b.17.9 V, about 7.5%
• c.8.9 V, about 3.7%✓
• d.2.2 V, about 0.9%

VD = 2 × 12.9 × 24 × 150 ÷ 10,380 = 92,880 ÷ 10,380 ≈ 8.9 V, which is 8.9/240 ≈ 3.7%. The other options misplace the length, current, or divide by the wrong circular-mil value.

In the voltage-drop formula for a balanced 3-phase circuit, which multiplier replaces the factor of 2 used in single-phase calculations?

• a.2
• b.1
• c.3
• d.1.732✓

Three-phase voltage drop uses 1.732 (the square root of 3) in place of the single-phase factor of 2. Using 2 would be the single-phase form, and 1 or 3 are incorrect multipliers.

To reduce voltage drop on a long branch-circuit run without changing the load, what is the most effective method?

• a.Increase the conductor cross-sectional area (more circular mils)✓
• b.Increase the overcurrent device rating
• c.Lower the conductor insulation temperature rating
• d.Add additional terminations along the run

Voltage drop is inversely proportional to conductor circular mils, so using a larger conductor is the direct remedy. Increasing the breaker or changing insulation rating does not lower voltage drop, and extra terminations only add resistance and points of failure.

If the one-way length of a circuit run is doubled while current and conductor size stay the same, what happens to the voltage drop?

• a.It is halved
• b.It doubles✓
• c.It stays the same
• d.It quadruples

Voltage drop is directly proportional to conductor length, so doubling the length doubles the voltage drop. It does not stay constant or quadruple, and it certainly does not decrease.

Per 200.6(A), a grounded (neutral) conductor 6 AWG or smaller must be identified by which of the following?

• a.Green insulation
• b.Red insulation
• c.A continuous white or gray outer finish (or three white/gray stripes)✓
• d.Orange insulation

Section 200.6(A) requires 6 AWG and smaller grounded conductors to be white or gray, or to have three continuous white/gray stripes. Green is reserved for grounding, and red or orange are used for ungrounded (hot) conductors.2023 NEC §200.6(A)

Per 250.119, an equipment grounding conductor may be identified by which of the following?

• a.White insulation
• b.Gray insulation
• c.Blue insulation
• d.Green, green with yellow stripe, or bare✓

Section 250.119 permits equipment grounding conductors to be green, green with one or more yellow stripes, or bare. White and gray are reserved for grounded (neutral) conductors, and blue is used as an ungrounded conductor color.2023 NEC §250.119

Per 110.15, on a 4-wire delta-connected 120/240 V system, the high-leg (the conductor with the higher voltage to ground) must be identified by what color?

• a.Orange✓
• b.Blue
• c.White
• d.Green

Section 110.15 requires the high-leg conductor (about 208 V to ground) to be durably marked orange or by other effective means. White is for the neutral and green for grounding, and blue is a normal ungrounded color that would not warn of the high leg.2023 NEC §110.15

Which set of colors is NOT permitted for ungrounded (hot) conductors, because these colors are reserved for other uses?

• a.Black and red
• b.White, gray, and green✓
• c.Blue and brown
• d.Orange and yellow

White and gray are reserved for grounded (neutral) conductors and green (or green/yellow) for grounding, so none may be used for ungrounded conductors. Black, red, blue, brown, orange, and yellow are all acceptable ungrounded colors.2023 NEC §200.6

Per 210.5(C), where a building is supplied by more than one nominal voltage system, how must the ungrounded branch-circuit conductors be treated?

• a.All must be black
• b.All systems may share the same color
• c.Each system's ungrounded conductors must be identified (e.g., by color), with the means posted at each panelboard✓
• d.They may be left unmarked

Section 210.5(C) requires ungrounded conductors of each system to be identified by phase or line and system, with the identification method documented and readily available (posted) at each branch-circuit panelboard. Leaving them unmarked or using one color for all systems defeats the safety intent.2023 NEC §210.5(C)

Per 200.6(B), how may a grounded (neutral) conductor larger than 6 AWG be identified?

• a.It must be manufactured with white insulation only
• b.By wrapping green tape at each end
• c.By orange insulation
• d.By white/gray insulation, or by distinctive white/gray markings (such as tape) at each termination and accessible point✓

Section 200.6(B) allows grounded conductors larger than 6 AWG to be white or gray, or to be marked with distinctive white or gray encircling identification at terminations and where accessible. Green is for grounding and orange indicates a high leg, so neither identifies a neutral.2023 NEC §200.6(B)