Free 2A Practice Questions

Question 1

The nameplate on a dwelling's listed multimotor air-conditioning unit states a minimum circuit ampacity of 26.4 A and a maximum fuse or circuit-breaker rating of 45 A. Its conductors have a final allowable ampacity of 30 A after all applicable limitations, and a 40-A circuit breaker supplies the unit without starting problems. How should the inspector assess these two ratings under the 2020 NEC?

Accepted Answer

Both installed ratings meet the marked MCA and maximum breaker limit.

Answer

Increase conductor ampacity to at least 40 A to match the installed breaker.

Answer

Reduce the breaker to 30 A so it does not exceed conductor ampacity.

Answer

Increase conductor ampacity to at least 33 A by applying 125% to the MCA.

Question 2

The conductors in a buried PVC feeder raceway are dual-marked "THHN/THWN-2." The installer credits the sealed raceway ends for making them acceptable; sizing and fill are correct. Under the 2020 NEC, which assessment correctly addresses their location suitability?

Accepted Answer

Their THWN-2 marking makes them suitable for the wet location.

Answer

Sealing the ends allows this raceway to be classified as a dry location.

Answer

They must be replaced with cable specifically listed for direct burial.

Answer

The THHN marking overrides the additional THWN-2 wet-location rating.

Question 3

An exterior nonfused switch marked "EMERGENCY DISCONNECT, NOT SERVICE EQUIPMENT" has been added ahead of a dwelling's indoor service main. The indoor main remains the service disconnect, and the exterior enclosure is properly bonded. Under the 2020 NEC, what must be done with the indoor main bonding jumper?

Accepted Answer

Keep the main bonding jumper at the indoor service disconnect.

Answer

Remove it; the indoor main is now feeder equipment.

Answer

Move the jumper to the first branch-circuit panel supplied from the indoor main.

Answer

Remove the jumper if the outdoor switch is connected to a grounding electrode.

Question 4

Lights on one leg of a dwelling's multiwire branch circuit dim while lights on the other leg brighten. An electrician records 78 V and 162 V from the two ungrounded conductors to the shared neutral at a downstream junction box, with both load groups connected. Line-to-line voltage there is 240 V; both line-to-neutral readings at the supplying panel remain 120 V. Which defect best explains all of these findings?

Accepted Answer

An open or high-resistance shared-neutral connection between the panel and loads.

Answer

A high-resistance connection in the ungrounded conductor feeding the dimmed lamps.

Answer

An equipment grounding conductor disconnected between the panel and both load groups.

Answer

Both ungrounded branch-circuit conductors connected to the same leg of the panelboard.

Question 5

On a garage plan, a 20-inch-wide, 120/240-volt single-phase panel sits beside an interior partition. Its unobstructed working space spans the full cabinet width and extends 12 inches farther to the right: 32 inches wide, 40 inches deep from the cabinet front, and 80 inches high from the floor. The panel top is 72 inches above the floor; its door opens 100 degrees. Using the 2020 NEC, which plan-review comment on these dimensions is justified?

Accepted Answer

The working-space dimensions comply; centering the panel is unnecessary.

Answer

Increase the depth to 48 inches because the panel contains 240-volt circuits.

Answer

Recenter the panel to provide equal clear widths on both sides of the cabinet.

Answer

Raise the ceiling to provide 6 feet of clear space above the panel top.

Question 6

For a one-family dwelling with a single 120/240 V service, an NEC 2020 optional-method worksheet has a general-load subtotal of 34,000 VA before demand factors. This includes every applicable load except the heat-pump compressor and supplemental resistance heat. The heat-pump compressor is rated 4,800 VA; its 12,000 VA supplemental resistance heat can operate simultaneously with it. There is no other heating or cooling equipment. Apply 100% to the first 10,000 VA of general load and 40% to the remainder. After including the applicable HVAC demand, which is the smallest standard service rating that meets the load?

Accepted Answer

150 A

Answer

125 A

Answer

175 A

Answer

200 A

Question 7

A stainless-steel ladder at a new permanently installed pool is connected to a separate ground rod measuring 12 ohms to earth. The ladder is attached to the pool structure but has no connection to its equipotential bonding system. The pump's equipment grounding conductor is intact, and its GFCI operates properly. Applying the 2020 NEC pool requirements, which inspection decision is justified for the ladder?

Accepted Answer

Connect the metal ladder to the existing pool equipotential bonding system.

Answer

Accept the ladder connection because the rod resistance is less than 25 ohms.

Answer

Install a second rod at least 6 feet away to complete the ladder grounding.

Answer

Accept the ladder connection after documenting the successful pool-pump GFCI test.

Question 8

A fall-of-potential test documents 18 ohms to earth for a dwelling service's only grounding electrode: a properly installed, listed rod with 8 feet of soil contact. No other qualifying electrodes are present. Under the 2020 NEC, how does this result affect the electrode requirement?

Accepted Answer

The rod meets the exception permitting a single electrode.

Answer

A second electrode remains mandatory despite this result.

Answer

The electrode must be replaced because resistance must be below 5 ohms.

Answer

The rod may also replace the equipment grounding conductors in feeders.

Question 9

Replacing an enclosed recessed LED luminaire with an enclosed surface-mounted LED would leave the new fixture on a closet ceiling, 9 inches from the nearest point of the code-defined storage space. The recessed fixture also has 9 inches of clearance. The proposed fixture is not identified for installation within closet storage space. Under the 2020 NEC, how does this substitution affect compliance?

Accepted Answer

Only the surface-mounted replacement fails the required storage-space clearance.

Answer

The proposed fixture is acceptable; all enclosed LEDs use the 6-inch clearance.

Answer

Neither fixture is acceptable; both must be at least 12 inches from storage.

Answer

The recessed fixture needs more clearance; surface-mounted LEDs have the smaller minimum.

Question 10

Fourteen inches of cover separates the top of a direct-buried UF-B cable from finished grade where it crosses a private driveway used only for a one-family dwelling. The cable supplies driveway lights on a 120 V, 20 A branch circuit protected by GFCI at its origin. Apply Table 300.5 of the 2020 NEC to evaluate the measured cover.

Accepted Answer

The 14-inch cover satisfies the requirement for this circuit and location.

Answer

Increase cover to 18 inches because a dwelling driveway excludes the GFCI allowance.

Answer

Increase cover to 24 inches because all direct-buried UF cable needs that depth.

Answer

Use raceway; UF cable cannot cross a driveway.

Free 2A Practice Questions

Domain 1: Cabinets, Panelboards, Switchboards, Boxes, and Conduit Bodies

Question 1

Domain 2: Calculations of Load

Question 2

Domain 4: Conductors and Overcurrent Protection on the Load Side of the Service

Question 3

Domain 5: Lighting and Utilization Equipment

Question 4

Question 5

Domain 6: Service Equipment and Conductors on the Supply Side of the Service

Question 6

Question 7

Domain 7: Special Installations or Constructions

Question 8

Domain 9: Wiring Methods

Question 9

Question 10

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