ICC E2 Commercial Electrical Inspector — Questions and Answers

Question 1: In patient care vicinities, receptacles and fixed electrical equipment are required to be grounded by what means?

An insulated copper equipment grounding conductor (Correct answer)
A bare aluminum conductor
A flexible metal conduit without a bonding jumper
The metal raceway only

Correct answer: An insulated copper equipment grounding conductor

NEC 517.13 requires that in patient care vicinities, the grounding terminals of all receptacles and all non-current-carrying conductive surfaces of fixed electrical equipment be grounded by an insulated copper equipment grounding conductor. This conductor must be sized according to Table 250.122 and installed in a metal raceway.

Question 2: Per NEC Table 430.52, the maximum rating for a non-time-delay fuse used for branch-circuit short-circuit protection of a Design B squirrel cage motor is:

175% of FLA
250% of FLA
400% of FLA
300% of FLA (Correct answer)

Correct answer: 300% of FLA

Table 430.52 permits non-time-delay fuses rated up to 300% of the motor's FLA for branch-circuit short-circuit and ground-fault protection.

Question 3: A motor feeder supplies three motors with table FLA values of 40A, 25A, and 15A. What is the minimum feeder conductor ampacity per NEC 430.24?

90A (Correct answer)
100A
110A
80A

Correct answer: 90A

Feeder ampacity = (1.25 × 40A) + 25A + 15A = 50A + 25A + 15A = 90A per NEC 430.24.

Question 4: What minimum load must be calculated for each required commercial sign or outline lighting outlet per NEC 220.14(F)?

1,200 VA (Correct answer)
900 VA
1,500 VA
600 VA

Correct answer: 1,200 VA

NEC 220.14(F) mandates a minimum 1,200 VA for each required sign or outline lighting outlet in commercial occupancies.

Question 5: Type MC cable installed in a plenum (environmental air space) must be:

Prohibited — only raceways are allowed in plenums
Limited to 10-foot sections
Encased in EMT conduit
Listed as plenum-rated (Type MC-HL or equivalent) (Correct answer)

Correct answer: Listed as plenum-rated (Type MC-HL or equivalent)

NEC 330.10(A)(11) permits MC cable in plenums only when listed and labeled for use in such spaces (plenum-rated jacket).

Question 6: A 480V, 3-phase transformer feeding a 120/208V panelboard in a commercial building must have its secondary protected at no more than what percentage of the transformer's rated secondary current when using a standard fuse?

250%
300%
125% (Correct answer)
100%

Correct answer: 125%

NEC 450.3(B) allows secondary overcurrent protection up to 125% of the transformer's rated secondary current for a supervised installation.

Question 7: Under NEC 800.113, communications cables installed in commercial buildings in spaces used for environmental air handling must be:

Riser-rated (CMR)
General-purpose (CM)
Plenum-rated (CMP) (Correct answer)
Conduit-only with no cable jacketing requirement

Correct answer: Plenum-rated (CMP)

NEC 800.113 requires plenum-rated (CMP) cables in air-handling spaces because these cables produce minimal smoke and toxic fumes if involved in a fire.

Question 8: What is the minimum working space depth for 277/480V equipment under Condition 3 per NEC 110.26(A)(1)?

5 feet (Correct answer)
3.5 feet
6 feet
4 feet

Correct answer: 5 feet

Per NEC 110.26(A)(1) Table, voltages from 151V to 600V under Condition 3 require a minimum working space depth of 5 feet.

Question 9: What NEC section addresses the grounding of a separately derived transformer system with a primary voltage over 1000V?

NEC 250.20
NEC 250.30 (Correct answer)
NEC 450.10
NEC 430.9

Correct answer: NEC 250.30

NEC 250.30 covers grounding of separately derived AC systems, including transformer secondaries at any voltage.

Question 10: Per NEC 110.15 and 230.56, the high-leg conductor of a 4-wire, 3-phase delta system shall be identified by the color:

Red
Orange (Correct answer)
Blue
Yellow

Correct answer: Orange

NEC 110.15 and 230.56 require the high-leg conductor (the phase with the highest voltage to ground, approximately 208V) in a 4-wire delta system to be identified with orange color.

Question 11: Which NEC table provides full-load current values for single-phase AC motors used for conductor and protection sizing?

Table 430.249
Table 430.248 (Correct answer)
Table 430.247
Table 430.250

Correct answer: Table 430.248

Table 430.248 lists FLA values for single-phase AC motors, which are used in place of nameplate values for conductor and overcurrent device sizing.

Question 12: An emergency system transfer switch must be listed and approved for emergency use and must transfer all _______ conductors simultaneously.

Grounded (neutral)
Ungrounded (hot) (Correct answer)
Equipment grounding
All circuit conductors including neutral

Correct answer: Ungrounded (hot)

NEC 700.5 requires the transfer switch to simultaneously transfer all ungrounded conductors, ensuring full circuit switching without backfeed hazards.

Question 13: The disconnecting means for a motor controller and the motor shall have an ampere rating of at least what percentage of the motor's full-load current?

100%
115% (Correct answer)
80%
125%

Correct answer: 115%

NEC 430.110(A) requires that the disconnecting means have an ampere rating of at least 115% of the motor's full-load current rating as determined by the FLC tables in Article 430. This ensures the disconnect can safely interrupt the locked-rotor current of the motor. It must also have a sufficient horsepower rating per 430.109.

Question 14: An autotransformer used for reduced-voltage motor starting must have its common winding connected to:

The line side only
The load side only
Both line and load conductors (Correct answer)
A grounded neutral point

Correct answer: Both line and load conductors

An autotransformer has a single continuous winding where the common winding section is shared between the primary and secondary circuits.

Question 15: During a plan review, the electrical drawings show conductors with 75°C termination ratings on equipment with 60°C terminal ratings. What is the correct action?

Accept the plans if the overcurrent device is rated for 75°C conductors
Require the conductors to be sized using the 60°C column of NEC Table 310.16 to match the terminal rating per NEC 110.14(C) (Correct answer)
Allow the installation if the conductors are in conduit with adequate fill
Accept the plans since higher-rated conductors always exceed minimum requirements

Correct answer: Require the conductors to be sized using the 60°C column of NEC Table 310.16 to match the terminal rating per NEC 110.14(C)

NEC 110.14(C) requires that conductor ampacity be determined based on the lowest temperature rating among all connected devices, so 60°C terminals require using the 60°C column.

Question 16: Per NEC 430.37, how many overload sensing elements are required for a 3-wire, 3-phase motor with no neutral conductor?

3 elements (Correct answer)
1 element
2 elements
4 elements

Correct answer: 3 elements

NEC 430.37 requires one overload sensing element in each of the three ungrounded phase conductors for a 3-wire, 3-phase motor.

Question 17: For 'all other' commercial occupancies per NEC Table 220.42, what demand factor applies to lighting loads exceeding 50,000 VA?

35%
100%
75%
50% (Correct answer)

Correct answer: 50%

NEC Table 220.42 allows a 50% demand factor on lighting loads over 50,000 VA for most commercial occupancies.

Question 18: When a motor control circuit is derived from a control transformer, NEC 430.72(B) requires the control circuit conductor to be protected at no more than:

The ampacity of the smallest conductor in the circuit (Correct answer)
100% of the transformer secondary output current
300% of the control transformer secondary FLA
The next standard overcurrent device above the conductor ampacity

Correct answer: The ampacity of the smallest conductor in the circuit

NEC 430.72(B) requires control circuit conductors to be protected by an OCPD rated no more than the ampacity of the smallest conductor.

Question 19: What NEC section governs the minimum size of branch circuit conductors for general lighting loads?

NEC 215.2
NEC 210.19 (Correct answer)
NEC 310.15
NEC 230.42

Correct answer: NEC 210.19

NEC 210.19 specifies the minimum ampacity and size of branch circuit conductors.

Question 20: Under NEC 700, which of the following is NOT an acceptable alternate power source for an emergency system?

Generator set
Stored electrical energy (batteries)
Unit equipment with integral battery
Separate service from a different utility substation on the same grid section (Correct answer)

Correct answer: Separate service from a different utility substation on the same grid section

A separate service from the same utility grid section does not qualify because a single utility failure could knock out both sources; true independence is required.

Question 21: A commercial branch circuit supplies a piece of equipment that operates continuously. The equipment nameplate shows 16 amperes at 120V. What is the minimum branch circuit overcurrent device rating per NEC 210.20?

20 amperes (Correct answer)
25 amperes
30 amperes
15 amperes

Correct answer: 20 amperes

16A × 1.25 = 20A; NEC 210.20(A) requires the OCPD to be rated at least 125% of continuous load, giving a 20A minimum device.

Question 22: Per NEC 430.110(A), the ampere rating of the motor circuit disconnecting means must be at least what percentage of the motor's full-load current rating?

150%
100%
115% (Correct answer)
125%

Correct answer: 115%

NEC 430.110(A) requires the motor disconnecting means to have an ampere rating of at least 115% of the motor's full-load current rating.

Question 23: Per NEC 215.10, feeder ground-fault protection of equipment is required for solidly grounded wye services exceeding what voltage and ampere rating?

277/480V services over 1000 amperes
Any 480V service over 800 amperes
120/208V services over 400 amperes
Solidly grounded wye services of more than 150V to ground not exceeding 600V and 1000 amperes or more (Correct answer)

Correct answer: Solidly grounded wye services of more than 150V to ground not exceeding 600V and 1000 amperes or more

NEC 215.10 requires feeder GFPE on solidly grounded wye services with more than 150V to ground, not exceeding 600V, rated 1000A or more.

Question 24: Under NEC 310.15(A)(3), when can an engineer use an ampacity that differs from the NEC tables?

When using the engineering supervision method with a qualified engineer (Correct answer)
Whenever the conductor is larger than 750 kcmil
Only when approved by the local AHJ in writing
When conduit fill does not exceed 40%

Correct answer: When using the engineering supervision method with a qualified engineer

NEC 310.15(A)(3) permits ampacity to be calculated under engineering supervision using recognized calculation methods as an alternative to table values.

Question 25: A 2/0 AWG THWN copper conductor is to be installed in an area with an ambient temperature of 110°F (43°C). What is its approximate allowable ampacity?

123 A
158 A
144 A (Correct answer)
175 A

Correct answer: 144 A

From Table 310.16, a 2/0 AWG THWN copper conductor has a base ampacity of 175A at 75°C. Using Table 310.15(B)(1), the correction factor for 41-45°C (which includes 43°C) in the 75°C column is 0.82. The adjusted ampacity is 175A * 0.82 = 143.5A.

Question 26: In Class I, Division 2 locations, which of the following wiring methods is NOT permitted?

Intermediate metal conduit (IMC)
Rigid metal conduit (RMC)
Electrical metallic tubing (EMT) (Correct answer)
Type MI cable

Correct answer: Electrical metallic tubing (EMT)

Electrical metallic tubing (EMT) is not permitted in Class I, Division 2 locations because it uses set-screw or compression fittings that do not provide adequate protection against the hazardous atmosphere.

Question 27: Per NEC 430.62(A), the feeder overcurrent protective device for a group of motors shall not exceed the rating of:

125% of the total FLA of all motors combined
The sum of all individual branch-circuit device ratings
250% of the largest motor's FLA alone
The largest permitted branch-circuit device for the biggest motor, plus the FLA of all other motors (Correct answer)

Correct answer: The largest permitted branch-circuit device for the biggest motor, plus the FLA of all other motors

NEC 430.62(A) limits the feeder overcurrent device to the maximum permitted branch-circuit protective device rating for the largest motor plus the FLA of all other motors.

Question 28: When installing an isolated power system, the maximum total length of the branch circuit conductors on the secondary side of the isolation transformer is:

50 feet (Correct answer)
100 feet
25 feet
No limit if properly sized

Correct answer: 50 feet

NEC 517.160(A)(3) limits the length of secondary conductors of an isolated power system to 50 feet to minimize distributed capacitance that degrades isolation.

Question 29: A commercial service equipment rated 1200A or more is being installed. Which of the following markings is specifically required by NEC 110.24 to be field-applied to this equipment?

The arc-flash hazard boundary
The maximum available fault current and the date of calculation (Correct answer)
The date of the last maintenance check
The name of the installing contractor

Correct answer: The maximum available fault current and the date of calculation

NEC 110.24(A) requires service equipment in other than dwelling units to be legibly marked in the field with the maximum available fault current. The marking must also include the date the fault-current calculation was performed. This information is crucial for ensuring the equipment's short-circuit current rating is adequate.

Question 30: Nonmetallic conduit (PVC) is generally not permitted in which of the following locations?

Concrete slab on grade
Underground direct burial
Wet locations outdoors
Hazardous locations (Class I, Division 1) (Correct answer)

Correct answer: Hazardous locations (Class I, Division 1)

NEC 352.12(E) prohibits Schedule 40/80 PVC in hazardous locations where flammable vapors are present (Class I, Div 1) unless specifically listed for such use.

Question 31: A UPS system used as an emergency power source for life-safety loads must comply with:

NFPA 13 only
NEC Article 702 only
NEC Article 700 and be listed for emergency use (Correct answer)
UL 508A industrial control panel standards only

Correct answer: NEC Article 700 and be listed for emergency use

A UPS serving life-safety loads must comply with NEC Article 700 requirements and be listed as suitable for emergency service.

Question 32: What is the minimum burial depth required for RMC installed under a commercial parking lot (not a highway)?

12 inches
24 inches
18 inches
6 inches (Correct answer)

Correct answer: 6 inches

NEC Table 300.5 requires only 6 inches of cover for RMC installed under a parking lot or driveway not subject to heavy vehicle traffic.

Question 33: A continuous-duty motor has a nameplate current rating of 40A and a service factor of 1.15. What is the maximum rating for a separate overload protection device for this motor?

40 A
50 A (Correct answer)
60 A
46 A

Correct answer: 50 A

According to NEC 430.32(A)(1), for a motor with a service factor of 1.15 or greater, the separate overload device shall be selected to trip at no more than 125% of the motor nameplate current rating. The calculation is 40A * 1.25 = 50A. This protects the motor from sustained overcurrents without nuisance tripping.

Question 34: A 25,000 sq ft office building is being permitted. What is the minimum general lighting load before applying any demand factors?

50,000 VA
75,000 VA
87,500 VA (Correct answer)
125,000 VA

Correct answer: 87,500 VA

Office occupancies use 3.5 VA/sq ft per NEC Table 220.12, so 25,000 × 3.5 = 87,500 VA.

Question 35: Per NEC 430.102(A), the motor controller disconnecting means must be located within sight of the controller. 'Within sight' is defined as:

In the same room with no obstructions
Visible and not more than 50 feet away (Correct answer)
Within 25 feet and unobstructed
On the same wall as the controller

Correct answer: Visible and not more than 50 feet away

NEC Article 100 defines 'within sight' as visible and not more than 50 feet from one another.

Question 36: Per NEC 230.24(B), service conductors run above a roof surface must maintain a minimum clearance above the roof of:

8 feet
18 inches for the general case (Correct answer)
36 inches
3 feet

Correct answer: 18 inches for the general case

NEC 230.24(B) generally requires 8 feet of clearance, but the standard minimum above a roof surface where the conductors pass through is 18 inches for the general case with a 300V or less limitation.

Question 37: When inspecting a commercial service, an inspector finds the neutral bar and equipment ground bar are bonded together in a subpanel fed from the main service. This is:

Permitted only for three-phase subpanels
Required for proper grounding
Acceptable if the subpanel is within 30 feet of the main panel
A violation that creates parallel return paths for normal current (Correct answer)

Correct answer: A violation that creates parallel return paths for normal current

NEC 250.142(B) prohibits bonding the grounded conductor to the equipment grounding terminal in subpanels; doing so creates objectionable parallel neutral current paths through grounding conductors.

Question 38: In an aircraft hangar per NEC Article 513, the area within 5 feet horizontally from aircraft power plants is classified as:

Class II, Division 2
Unclassified with proper ventilation
Class I, Division 2 (Correct answer)
Class I, Division 1

Correct answer: Class I, Division 2

NEC 513.3 classifies areas within 5 feet horizontally from aircraft power plants and fuel tanks up to 5 feet above the upper surface as Class I, Division 2.

Question 39: In a general care area of a health care facility, what is the minimum number of receptacles required at each patient bed location?

Eight (Correct answer)
Ten
Four
Six

Correct answer: Eight

According to NEC 517.18(B), each patient bed location in a general care area must be supplied by at least two branch circuits, and a minimum of eight receptacles must be provided. These receptacles can be single, duplex, or a combination.

Question 40: Under NEC 110.16, arc flash hazard warning labels are required on which commercial electrical equipment?

Only service entrance equipment rated 1,200A or more
All electrical equipment in any occupancy regardless of voltage
Switchboards, switchgear, panelboards, industrial control panels, and motor control centers likely to require examination while energized (Correct answer)
Only equipment rated above 480V phase-to-phase

Correct answer: Switchboards, switchgear, panelboards, industrial control panels, and motor control centers likely to require examination while energized

NEC 110.16 mandates arc flash warning labels on switchboards, switchgear, panelboards, industrial control panels, and MCCs likely to require energized work.

Question 41: When inspecting a commercial occupancy's air-conditioning system with a hermetic refrigerant motor-compressor, the branch circuit overcurrent protection is permitted to be sized up to:

225% of the nameplate rated-load current (Correct answer)
125% of the nameplate rated-load current
175% of the nameplate rated-load current
300% of the nameplate rated-load current

Correct answer: 225% of the nameplate rated-load current

NEC 440.22(A) allows the branch circuit overcurrent protection for a hermetic refrigerant motor-compressor to be sized up to 225% of the nameplate rated-load current.

Question 42: What is the minimum bend radius for a 1-inch EMT conduit field bend to the inside of the bend?

2.5 inches
5 inches
8 inches
4 inches (Correct answer)

Correct answer: 4 inches

NEC Table 344.24 (referenced by 358.24) specifies a minimum 4-inch inside bend radius for 1-inch trade size conduit.

Question 43: Where must the equipment grounding conductor in a patient care area be insulated?

Only in wet locations
Only where it is exposed
Only within 6 feet of the patient bed
Throughout its entire length from panel to receptacle (Correct answer)

Correct answer: Throughout its entire length from panel to receptacle

NEC 517.13(B) requires the equipment grounding conductor to be insulated throughout its entire length in patient care branch circuit wiring.

Question 44: Per NEC 430.6(A)(1), which current value is used for sizing motor branch circuit conductors and short-circuit/ground-fault protective devices?

Locked rotor current rating
Motor nameplate ampere rating
Service factor current
Values from Tables 430.247 through 430.250 (Correct answer)

Correct answer: Values from Tables 430.247 through 430.250

NEC 430.6(A)(1) requires using table values from 430.247–430.250, not the motor nameplate, for conductor and short-circuit/ground-fault protection sizing.

Question 45: According to NEC 110.26(C)(1), how many means of egress are required for a room with electrical equipment rated 1200A or more and over 6 feet wide when the room exceeds 50 feet in length?

One entrance at either end
Three entrances distributed along the length
One entrance with a panic bar
Two entrances located at each end of the working space (Correct answer)

Correct answer: Two entrances located at each end of the working space

NEC 110.26(C)(1) Exception requires two entrances located at each end of the working space for rooms exceeding 50 feet in length with large equipment.

Question 46: NEC 700.12 requires emergency system sources to supply full load within how many seconds of normal power failure?

30 seconds
10 seconds (Correct answer)
15 seconds
5 seconds

Correct answer: 10 seconds

Emergency systems must restore power within 10 seconds of normal source failure per NEC 700.12.

Question 47: Under NEC 110.34, what is the minimum depth of working space required for equipment rated over 600V nominal in a commercial installation (Condition 2)?

8 feet
4 feet
6 feet (Correct answer)
3 feet

Correct answer: 6 feet

NEC Table 110.34(A) requires a minimum working space depth of 6 feet for Condition 2 (grounded surfaces on one side) for equipment over 600V.

Question 48: A 20 HP, 460V, 3-phase motor has a table FLA of 27A. What is the minimum branch circuit conductor ampacity required by NEC 430.22?

31.1A
33.75A (Correct answer)
40.5A
27A

Correct answer: 33.75A

125% of 27A = 33.75A is the minimum conductor ampacity per NEC 430.22 for continuous-duty operation.

Question 49: When inspecting a variable frequency drive (VFD) installation, which conductor issue is most critical to verify?

Wire insulation color
Conductor ampacity derating for harmonic heating (Correct answer)
Use of aluminum conductors only
Minimum 10 AWG branch circuit

Correct answer: Conductor ampacity derating for harmonic heating

VFDs produce harmonics that cause additional heating in conductors, requiring ampacity derating per NEC 310.15(A)(2).

Question 50: Per NEC 430.24, the minimum feeder conductor ampacity for a group of motors equals the sum of all motor FLA values plus an additional percentage of which motor's FLA?

15% of the smallest motor's FLA
25% of the largest motor's FLA (Correct answer)
50% of the total combined FLA
35% of the average motor's FLA

Correct answer: 25% of the largest motor's FLA

NEC 430.24 requires feeder ampacity equal to 125% of the largest motor's FLA plus 100% of all other motors' FLA, effectively adding 25% of the largest motor.

Question 51: When inspecting a commercial pool pump motor installation, which bonding requirement is unique compared to standard motor installations?

All metal parts within 5 feet of the pool, including the motor, must be bonded together with a solid copper conductor no smaller than 8 AWG (Correct answer)
The motor frame must be bonded to the equipment grounding conductor only
The pool pump motor requires a dedicated grounding rod
Bonding is not required if GFCI protection is provided

Correct answer: All metal parts within 5 feet of the pool, including the motor, must be bonded together with a solid copper conductor no smaller than 8 AWG

NEC 680.26 requires all metal parts within 5 feet of the pool water surface to be bonded together using a solid copper bonding conductor not smaller than 8 AWG solid.

Question 52: How must emergency circuit wiring be installed relative to other non-emergency wiring?

It only needs to be separated from communications wiring.
It can be in the same raceway if separated by a partition.
It must be kept entirely independent of all other wiring and equipment. (Correct answer)
It can be in the same junction box as long as the conductors are from the same system.

Correct answer: It must be kept entirely independent of all other wiring and equipment.

NEC 700.10(B) requires that all boxes, raceways, and cables of emergency circuits be installed and maintained as completely independent of all other wiring and equipment. This separation prevents problems in general wiring systems from affecting the emergency system's operation.

Question 53: Per NEC 430.52(C)(2), if the maximum standard inverse time breaker size cannot carry the motor's starting current, the breaker rating may be increased to a maximum of:

600% of FLA
400% of FLA (Correct answer)
700% of FLA
300% of FLA

Correct answer: 400% of FLA

NEC 430.52(C)(2) allows the inverse time breaker to be increased to a maximum of 400% of FLA when the standard 250% cannot handle motor starting current.

Question 54: Which of the following best describes a Class II, Division 1 location under NEC Article 502?

An area where combustible dust is in suspension in the air under normal operating conditions (Correct answer)
An area adjacent to a Class I location where vapors may occasionally drift
An area where flammable gases exist continuously under normal conditions
An area where ignitable fibers are stored in open containers

Correct answer: An area where combustible dust is in suspension in the air under normal operating conditions

Class II, Division 1 locations have combustible dust in suspension in the air continuously or intermittently under normal operating conditions.

Question 55: A feeder supplying a 3-phase, 208-volt system has a calculated load of 120 amperes. What size copper conductor with THHN insulation is required, assuming no derating factors apply?

#2 AWG
#6 AWG
#3 AWG
#4 AWG (Correct answer)

Correct answer: #4 AWG

According to NEC Table 310.16, #4 AWG copper with THHN insulation has an ampacity of 125 amperes, which is sufficient for the calculated load of 120 amperes. Always refer to the NEC ampacity tables and consider any applicable adjustments or corrections.

Question 56: An E2 inspector observes that a 277V fluorescent lighting circuit has no GFCI protection in a commercial kitchen wet location. Which code section applies?

NEC 210.8(B) only covers 120V receptacles in commercial kitchens
NEC 230.95 requires GFPE for services over 150V
NEC 210.8(B) requires GFCI for 277V circuits in commercial wet locations (Correct answer)
NEC 215.9 mandates AFCI for all lighting circuits

Correct answer: NEC 210.8(B) requires GFCI for 277V circuits in commercial wet locations

NEC 210.8(B) requires GFCI protection for personnel in commercial kitchens, including 277V circuits used in wet locations.

Question 57: What is the calculated general lighting load, after demand factors, for a 60,000 sq. ft. commercial office building?

210,000 VA
98,750 VA
111,250 VA (Correct answer)
105,000 VA

Correct answer: 111,250 VA

Per NEC Table 220.12, the unit load for an office is 3.5 VA/sq. ft. The total load is 60,000 * 3.5 = 210,000 VA. According to Table 220.42, the first 12,500 VA is taken at 100%, and the remainder (197,500 VA) is taken at 50%, resulting in a total calculated load of 111,250 VA (12,500 + (197,500 * 0.5)).

Question 58: An inspector is examining a 10 HP, 460-volt, 3-phase squirrel-cage motor. According to NEC Table 430.250, its Full Load Current (FLC) is 14A. What is the maximum permitted rating for an inverse-time circuit breaker used for branch-circuit short-circuit and ground-fault protection?

30A
35A (Correct answer)
25A
40A

Correct answer: 35A

NEC 430.52(C)(1) and Table 430.52 permit sizing an inverse-time circuit breaker for a polyphase squirrel-cage motor at a maximum of 250% of the motor's FLC. The FLC from Table 430.250 is 14A. Calculation: 14A x 250% = 35A. Since 35A is a standard size listed in NEC 240.6(A), it is the maximum permitted rating.

Question 59: A commercial building has electric resistance heating only with no cooling system. How must the heating load be treated in the service calculation?

At 125% as a continuous load per NEC 215.2 (Correct answer)
At 80% as a feeder correction factor
At 65% using the electric heating demand factor
At 100% since there is no competing cooling load

Correct answer: At 125% as a continuous load per NEC 215.2

Electric heating that operates continuously for 3 or more hours is a continuous load and must be calculated at 125% per NEC 215.2.

Question 60: When inspecting a commercial fire alarm system, the inspector notes that the NAC (Notification Appliance Circuit) uses Class B wiring. What distinguishes Class B from Class A wiring?

Class B uses shielded cable; Class A does not
Class B allows wireless devices only
Class B requires 2-hour fire-rated cable throughout
Class B has no return path and a single open fault can disable devices beyond the fault (Correct answer)

Correct answer: Class B has no return path and a single open fault can disable devices beyond the fault

Class B (Style B) NAC circuits do not loop back to the panel, so a single wire break can disable all devices beyond that point.

Question 61: Per NEC Article 230, how many sets of service entrance conductors are permitted to supply a single building from a single service drop?

Only one set is always required
Unlimited sets with POCO approval
No more than two sets
Up to six sets under specific conditions (Correct answer)

Correct answer: Up to six sets under specific conditions

NEC 230.40 permits up to six sets of service entrance conductors from a single service drop or lateral under defined conditions.

Question 62: Per NEC Table 220.55, what is the maximum demand used when a commercial establishment has a single household cooking unit rated 12 kW?

15 kW
10 kW
12 kW
8 kW (Correct answer)

Correct answer: 8 kW

NEC Table 220.55 permits a maximum demand of 8 kW for a single range rated 12 kW or less.

Question 63: Per NEC 215.12, feeder conductors must be identified by means of:

Field-applied markings at each end and at accessible points (Correct answer)
Separate conduit from branch circuits
Color coding only
A tag at every junction box

Correct answer: Field-applied markings at each end and at accessible points

NEC 215.12 requires feeder conductors to be legibly marked at terminations and wherever accessible using field-applied identification.

Question 64: A feeder supplies two motors. The largest motor is protected by a 150A branch-circuit breaker, and the second motor has an FLC of 40A. What is the maximum size circuit breaker allowed for the feeder protection?

175 A (Correct answer)
190 A
225 A
200 A

Correct answer: 175 A

Per NEC 430.62(A), the feeder overcurrent device rating shall not be greater than the largest branch-circuit protective device rating plus the sum of the FLCs of the other motors on the feeder. The calculation is 150A (largest branch OCPD) + 40A (FLC of other motor) = 190A. Since 190A is not a standard size, the next lower standard size of 175A must be used.

Question 65: What is the maximum distance allowed between a motor disconnect and the motor it serves, per NEC 430.102(B)?

The disconnect must be within 10 feet
The disconnect must be in the same room
The disconnect must be within sight of the motor (Correct answer)
No distance limit if a lockable disconnect is provided

Correct answer: The disconnect must be within sight of the motor

NEC 430.102(B) requires the disconnecting means to be within sight of the motor location and driven machinery, unless it is lockable in the open position.

Question 66: For hermetic refrigerant motor-compressors used in air-conditioning and refrigerating equipment, which NEC article governs motor circuit sizing instead of the standard Article 430 tables?

Article 445
Article 450
Article 460
Article 440 (Correct answer)

Correct answer: Article 440

Article 440 governs air-conditioning and refrigerating equipment including hermetic refrigerant motor-compressors, which have unique sizing rules distinct from general Article 430 provisions.

Question 67: A commercial building has 150 general-purpose duplex receptacles that are not used for general illumination. What is the calculated load for these receptacles after applying demand factors?

10,000 VA
27,000 VA
18,500 VA (Correct answer)
13,500 VA

Correct answer: 18,500 VA

According to NEC 220.14(I), each receptacle outlet is calculated at 180 VA. The total load is 150 * 180 VA = 27,000 VA. Per Table 220.44, the first 10 kVA is at 100% and the remainder is at 50%, resulting in a calculated load of 18,500 VA (10,000 + (17,000 * 0.5)).

Question 68: In a commercial occupancy, Type AC cable (Armored Cable) must be secured within how many inches of every box or fitting?

12 inches (Correct answer)
18 inches
24 inches
6 inches

Correct answer: 12 inches

NEC 320.30(C) requires AC cable to be secured within 12 inches of every outlet box, junction box, or fitting.

Question 69: What type of overcurrent protection device is typically used to protect a motor circuit?

Non-time-delay fuse
Circuit breaker
Ground-fault circuit interrupter (GFCI)
Time-delay fuse (Correct answer)

Correct answer: Time-delay fuse

Time-delay fuses are used in motor circuits to allow the motor to handle its inrush current (starting current) without tripping immediately. This is crucial for motors, which draw higher current during startup.

Question 70: Six current-carrying 12 AWG THHN conductors are installed in a single conduit at an ambient temperature of 30°C. What is the derated ampacity per conductor?

20A
24A
15A (Correct answer)
12A

Correct answer: 15A

Six conductors require a 0.80 adjustment; 12 AWG THHN at 90°C is 30A, so 30A × 0.80 = 24A, but limited to 20A × 0.80 = 16A at 75°C terminal rating.

Question 71: A set of plans shows lighting circuits wired with #14 AWG conductors, protected by a 20-amp circuit breaker. What is the issue?

Conductors are undersized for the breaker rating (Correct answer)
No issue, this is code-compliant
Lighting circuits cannot use #14 AWG conductors
The circuit breaker is undersized for the load

Correct answer: Conductors are undersized for the breaker rating

According to the National Electrical Code (NEC), #14 AWG copper conductors are typically rated for a maximum overcurrent protection of 15 amps (NEC Table 310.16 and 240.4(D)). Protecting #14 AWG conductors with a 20-amp circuit breaker creates a hazardous situation where the conductors could overheat and potentially cause a fire before the breaker trips. The breaker would not provide adequate protection for the smaller wire size.

Question 72: Which of the following is listed in NEC 430.109(A) as an acceptable type of motor disconnecting means?

General-use toggle switch for any motor size
Motor circuit switch rated in horsepower (Correct answer)
Branch circuit breaker on a general lighting panelboard for a 30 HP motor
Attachment plug and receptacle for motors over 2 HP on 300V circuits

Correct answer: Motor circuit switch rated in horsepower

NEC 430.109(A) lists motor circuit switches rated in horsepower as an approved type of disconnecting means for motor circuits.

Question 73: Per NEC Table 220.56, what demand factor applies to commercial kitchen equipment when there are only 2 cooking units?

90%
65%
100% (Correct answer)
80%

Correct answer: 100%

NEC Table 220.56 requires 100% demand factor when a commercial kitchen has only 1 or 2 units of cooking equipment.

Question 74: How many receptacles are required in a commercial office space measuring 400 square feet, according to general NEC guidelines?

6
4
10
8 (Correct answer)

Correct answer: 8

Per NEC Article 210.52(B), commercial office spaces typically require one receptacle per 50 square feet. For 400 square feet, 400 ÷ 50 = 8 receptacles. This ensures adequate power access for typical office equipment.

Question 75: Under OSHA 29 CFR 1910.333, de-energized electrical equipment must be locked out before work begins unless the employer can demonstrate that de-energizing would:

Require more than two workers to accomplish
Require special tools not on site
Save less than 30 minutes of downtime
Cause a greater hazard or is infeasible due to equipment design (Correct answer)

Correct answer: Cause a greater hazard or is infeasible due to equipment design

OSHA allows energized work only when de-energizing creates a greater hazard or is infeasible due to equipment design or operational limitations.

Question 76: What is the maximum time permitted for a Legally Required Standby System to be automatically connected to its power source after a normal power failure?

10 seconds
30 seconds
5 minutes
60 seconds (Correct answer)

Correct answer: 60 seconds

NEC 701.12 specifies that legally required standby systems must have automatic transfer equipment that restores power within 60 seconds of a normal power failure. These systems support critical operations like ventilation and smoke removal, which are important but less immediately life-threatening than those on the emergency system.

Question 77: Which conductor is NOT considered a current-carrying conductor for the purposes of applying adjustment factors from Table 310.15(C)(1)?

An equipment grounding conductor.
The neutral conductor of a 120/240V single-phase system.
An ungrounded 'hot' conductor in a single-phase circuit.
A neutral conductor of a balanced 3-phase, 4-wire, wye-connected system. (Correct answer)

Correct answer: A neutral conductor of a balanced 3-phase, 4-wire, wye-connected system.

According to NEC 310.15(E)(1), a neutral conductor that carries only the unbalanced current from other conductors of the same circuit is not required to be counted as a current-carrying conductor. This is common in balanced 3-phase, 4-wire, wye-connected systems.

Question 78: A rooftop HVAC unit on a commercial building is served by a disconnect switch mounted on the unit. The NEC requires this disconnect to be:

A fused safety switch only
Rated at 200% of the motor FLA
Located inside the unit's electrical compartment
Lockable in the open position (Correct answer)

Correct answer: Lockable in the open position

NEC 430.102(B) and 440.14 require the disconnecting means for HVAC equipment to be lockable in the open (off) position.

Question 79: An automatic transfer switch (ATS) for an emergency system must be listed and be capable of withstanding:

Available fault current at the point of installation (Correct answer)
Only the rated load current
125% of full load current
The utility transformer rating

Correct answer: Available fault current at the point of installation

Per NEC 700.5(A), transfer switches must be suitable for the available fault current at the point where they are installed.

Question 80: Which of the following wiring methods is permitted for use in a commercial building?

Nonmetallic-sheathed cable (NM)
Flat conductor cable (FCC)
Armored cable (AC)
Rigid metal conduit (RMC) (Correct answer)

Correct answer: Rigid metal conduit (RMC)

RMC is commonly used in commercial buildings due to its durability and protection against physical damage. NM cable is typically restricted to residential installations, while AC and FCC have limited commercial applications depending on specific conditions and locations per NEC requirements.

Question 81: A health care facility generator set used for the essential electrical system must be capable of picking up full load within:

30 seconds
5 seconds
10 seconds (Correct answer)
60 seconds

Correct answer: 10 seconds

Per NEC 517.30 and NFPA 110, the alternate source for a health care facility Type 1 EES must be capable of supplying power within 10 seconds of failure.

ICC E2 Commercial Electrical Inspector

The ICC E2 exam certifies inspectors to perform inspections of electrical system installations and alterations in commercial and industrial buildings, covering services, conductors, wiring methods, and special systems per the NFPA 70 National Electrical Code.

Questions

210 min

Time Limit

75%

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