NEC Quiz Template for Master Electrician
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Quiz 1: Wiring Methods & Materials (40 Questions)
Quiz 2: Equipment for General Use (12 Questions)
Quiz 3: General Electrical Knowledge (24 Questions)
Quiz 4: Communication Systems (6 Questions)
Quiz 5: Wiring & Protection (36 Questions)
Quiz 6: Special Equipment (6 Questions)
Quiz 7: Motors & Controls (8 Questions)
Quiz 8: Plan Reading (6 Questions)
Quiz 9: Special Conditions (8 Questions)
Quiz 10: Special Occupancies (4 Questions)
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Quiz 1: Wiring Methods & Materials
1. What is the minimum trade size of EMT for eight #12 AWG THHN conductors?
A) 1/2 inch
B) 3/4 inch
C) 1 inch
D) 1-1/4 inch
Answer:
B) 3/4 inch
Explanation:
Per NEC Chapter 9, Table 4, eight #12 AWG THHN conductors require a 3/4-inch EMT based on 40% fill calculations.
2. Which wiring method is permitted for direct burial without conduit?
A) NM-B
B) UF-B
C) THHN
D) MC
Answer:
B) UF-B
Explanation:
NEC 340.10(4) permits UF-B cable for direct burial; NM-B and THHN require conduit, and MC is not typically direct-buried.
3. What is the maximum number of bends in a single conduit run?
A) 180 degrees
B) 360 degrees
C) 540 degrees
D) 720 degrees
Answer:
B) 360 degrees
Explanation:
NEC 300.18 limits bends to 360 degrees (four 90-degree bends) to ensure ease of pulling conductors.
4. Which conduit type is suitable for wet locations?
A) EMT
B) PVC
C) FMC
D) AC Cable
Answer:
B) PVC
Explanation:
NEC 352.10 permits PVC conduit in wet locations; EMT and FMC need additional protection, and AC cable is not a conduit.
5. What is the minimum depth for direct-buried UF cable under a residential driveway?
A) 12 inches
B) 18 inches
C) 24 inches
D) 30 inches
Answer:
B) 18 inches
Explanation:
NEC Table 300.5 requires 18 inches for direct-buried cables under residential driveways.
6. Which wiring method is prohibited in Class I, Division 1 hazardous locations?
A) Rigid Metal Conduit
B) NM-B Cable
C) IMC
D) Threaded RMC
Answer:
B) NM-B Cable
Explanation:
NEC 501.10 prohibits NM-B cable in Class I, Division 1 hazardous locations due to lack of explosion-proof properties.
7. What is the maximum length of flexible metal conduit used as a grounding conductor?
A) 3 feet
B) 6 feet
C) 10 feet
D) No limit
Answer:
B) 6 feet
Explanation:
NEC 250.118(5) limits FMC to 6 feet when used as an equipment grounding conductor.
8. Which NEC article governs Type MC cable?
A) Article 300
B) Article 330
C) Article 334
D) Article 352
Answer:
B) Article 330
Explanation:
NEC Article 330 covers the use and installation of Type MC (Metal-Clad) cable.
9. What is required for cables run parallel to framing members?
A) 1-1/4 inch clearance from framing edge
B) Metal plates for protection
C) Conduit encasement
D) No special requirements
Answer:
A) 1-1/4 inch clearance from framing edge
Explanation:
NEC 300.4(A) requires cables to be 1-1/4 inches from the edge of framing members to avoid nail damage.
10. Which conductor insulation type is suitable for wet locations?
A) THHN
B) THWN
C) RHW
D) Both B and C
Answer:
D) Both B and C
Explanation:
NEC Table 310.104(A) lists THWN and RHW as suitable for wet locations; THHN is dry or damp only.
11. What is the minimum size of a raceway for a single conductor?
A) 1/2 inch
B) 3/4 inch
C) 1 inch
D) No minimum size
Answer:
D) No minimum size
Explanation:
NEC 300.17 and Chapter 9 Tables do not specify a minimum raceway size; it depends on conductor fill.
12. Which conduit requires threaded fittings in damp locations?
A) EMT
B) Rigid Metal Conduit
C) PVC
D) LFNC
Answer:
B) Rigid Metal Conduit
Explanation:
NEC 344.10 requires threaded fittings for RMC in damp locations for secure connections.
13. What is the maximum fill percentage for a conduit with three or more conductors?
A) 31%
B) 40%
C) 53%
D) 60%
Answer:
B) 40%
Explanation:
NEC Chapter 9, Table 1 specifies a 40% fill limit for conduits with three or more conductors.
14. Which cable type is permitted in concealed drywall installations?
A) NM-B
B) UF-B
C) MC
D) All of the above
Answer:
D) All of the above
Explanation:
NEC 334.10, 340.10, and 330.10 permit NM-B, UF-B, and MC cables in concealed drywall installations.
15. What is required when a conduit penetrates a fire-rated wall?
A) Fire caulk or sealant
B) Metal conduit only
C) No requirements
D) Insulated conductors
Answer:
A) Fire caulk or sealant
Explanation:
NEC 300.21 requires fire-rated sealant to maintain the fire resistance of walls penetrated by conduits.
16. Which NEC article covers Type NM cable?
A) Article 320
B) Article 330
C) Article 334
D) Article 340
Answer:
C) Article 334
Explanation:
NEC Article 334 governs the use and installation of Type NM (Nonmetallic-Sheathed) cable.
17. What is the minimum bending radius for 1-inch EMT?
A) 4 inches
B) 6 inches
C) 8 inches
D) 10 inches
Answer:
B) 6 inches
Explanation:
NEC 358.24 requires a minimum bending radius of 6 times the internal diameter for EMT; for 1-inch EMT, this is approximately 6 inches.
18. Which wiring method is permitted in exposed locations in a dwelling?
A) NM-B
B) EMT
C) UF-B
D) Both B and C
Answer:
D) Both B and C
Explanation:
NEC 358.10 and 340.10 permit EMT and UF-B in exposed locations; NM-B is restricted to concealed locations (NEC 334.15).
19. What is the maximum distance between supports for 3/4-inch PVC conduit?
A) 3 feet
B) 4 feet
C) 5 feet
D) 6 feet
Answer:
A) 3 feet
Explanation:
NEC Table 352.30 requires 3/4-inch PVC conduit to be supported every 3 feet.
20. Which conductor type is required for underground feeder circuits?
A) THHN
B) UF-B
C) NM-B
D) MC
Answer:
B) UF-B
Explanation:
NEC 340.10(4) requires UF-B cable for underground feeder circuits due to its suitability for wet locations and direct burial.
21. What is the minimum trade size of PVC conduit for six #10 AWG THWN conductors?
A) 1/2 inch
B) 3/4 inch
C) 1 inch
D) 1-1/4 inch
Answer:
B) 3/4 inch
Explanation:
NEC Chapter 9, Table 4 requires a 3/4-inch PVC conduit for six #10 AWG THWN conductors based on 40% fill.
22. Which cable is permitted for use in a plenum space?
A) NM-B
B) CMP
C) UF-B
D) MC
Answer:
B) CMP
Explanation:
NEC 800.179 requires CMP (Communications Plenum) cable for plenum spaces due to low smoke and flame properties.
23. What is the minimum depth for direct-buried Type MC cable?
A) 6 inches
B) 12 inches
C) 18 inches
D) 24 inches
Answer:
D) 24 inches
Explanation:
NEC Table 300.5 requires a 24-inch burial depth for Type MC cable unless protected by conduit.
24. Which conduit type is permitted in corrosive environments?
A) EMT
B) PVC
C) RMC
D) Both B and C
Answer:
D) Both B and C
Explanation:
NEC 352.10 and 344.10 permit PVC and RMC in corrosive environments; EMT is not suitable without coating.
25. What is the maximum length of liquidtight flexible metal conduit in a single run?
A) 3 feet
B) 6 feet
C) 10 feet
D) No limit
Answer:
D) No limit
Explanation:
NEC 350.30 does not specify a maximum length for LFMC, but support is required every 4.5 feet.
26. Which NEC article covers Type AC cable?
A) Article 320
B) Article 330
C) Article 334
D) Article 340
Answer:
A) Article 320
Explanation:
NEC Article 320 governs the use and installation of Type AC (Armored Cable).
27. What is the maximum distance between supports for 1-inch EMT?
A) 5 feet
B) 10 feet
C) 12 feet
D) 15 feet
Answer:
B) 10 feet
Explanation:
NEC Table 358.30 requires 1-inch EMT to be supported every 10 feet.
28. Which wiring method is permitted in a wet location without additional protection?
A) NM-B
B) UF-B
C) MC
D) EMT
Answer:
B) UF-B
Explanation:
NEC 340.10 permits UF-B in wet locations; NM-B, MC, and EMT require additional protection.
29. What is the minimum size of a conduit body for four #8 AWG conductors?
A) 3/4 inch
B) 1 inch
C) 1-1/4 inch
D) 1-1/2 inch
Answer:
C) 1-1/4 inch
Explanation:
NEC 314.28 requires a conduit body to accommodate the fill of four #8 AWG conductors, typically requiring 1-1/4 inch.
30. Which conductor type is permitted in a raceway in a damp location?
A) THHN
B) THWN
C) NM-B
D) UF-B
Answer:
B) THWN
Explanation:
NEC Table 310.104(A) permits THWN for damp locations; THHN is dry only, and NM-B/UF-B are not for raceways.
31. What is required for cables installed through bored holes in joists?
A) 1-1/4 inch from the nearest edge
B) Metal plates
C) Conduit encasement
D) No protection required
Answer:
A) 1-1/4 inch from the nearest edge
Explanation:
NEC 300.4(A)(1) requires cables through bored holes to be 1-1/4 inches from the nearest edge or protected.
32. Which NEC article covers rigid metal conduit?
A) Article 344
B) Article 348
C) Article 352
D) Article 358
Answer:
A) Article 344
Explanation:
NEC Article 344 governs the use and installation of Rigid Metal Conduit (RMC).
33. What is the maximum number of conductors in a 1/2-inch EMT conduit?
A) 4 #12 AWG
B) 6 #12 AWG
C) 9 #12 AWG
D) 12 #12 AWG
Answer:
C) 9 #12 AWG
Explanation:
NEC Chapter 9, Table 4 allows up to 9 #12 AWG conductors in 1/2-inch EMT based on 40% fill.
34. Which wiring method is permitted in a concrete slab?
A) NM-B
B) PVC
C) UF-B
D) Both B and C
Answer:
D) Both B and C
Explanation:
NEC 352.10 and 340.10 permit PVC conduit and UF-B cable in concrete slabs; NM-B is not permitted.
35. What is the minimum depth for rigid metal conduit under a parking lot?
A) 6 inches
B) 12 inches
C) 18 inches
D) 24 inches
Answer:
C) 18 inches
Explanation:
NEC Table 300.5 requires an 18-inch burial depth for RMC under vehicular traffic areas like parking lots.
36. Which conduit type is permitted in direct contact with earth?
A) EMT
B) RMC
C) FMC
D) LFMC
Answer:
B) RMC
Explanation:
NEC 344.10 permits RMC in direct contact with earth; EMT, FMC, and LFMC are not suitable without protection.
37. What is the maximum length of a flexible cord used for temporary wiring?
A) 25 feet
B) 50 feet
C) 100 feet
D) No limit
Answer:
D) No limit
Explanation:
NEC 590.4 does not specify a maximum length for temporary flexible cords, but they must be protected from damage.
38. Which NEC article covers electrical metallic tubing?
A) Article 344
B) Article 348
C) Article 352
D) Article 358
Answer:
D) Article 358
Explanation:
NEC Article 358 governs the use and installation of Electrical Metallic Tubing (EMT).
39. What is the minimum size of a conduit for two #6 AWG THWN conductors?
A) 1/2 inch
B) 3/4 inch
C) 1 inch
D) 1-1/4 inch
Answer:
B) 3/4 inch
Explanation:
NEC Chapter 9, Table 4 requires a 3/4-inch conduit for two #6 AWG THWN conductors based on 53% fill for two conductors.
40. Which wiring method is permitted in a masonry wall?
A) NM-B
B) EMT
C) MC
D) All of the above
Answer:
D) All of the above
Explanation:
NEC 334.10, 358.10, and 330.10 permit NM-B, EMT, and MC in masonry walls, provided properly installed.
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Quiz 2: Equipment for General Use
1. What is the maximum length of a flexible cord used to connect a portable luminaire in a dwelling unit?
A) 3 feet
B) 6 feet
C) 10 feet
D) No limit
Answer:
D) No limit
Explanation:
NEC 410.62(C) and 400.12 do not specify a maximum length for flexible cords used with portable luminaires in dwelling units, provided they are properly supported and protected.
2. What is the minimum mounting height for a wall-mounted luminaire above a bathroom sink?
A) 4 feet
B) 6 feet
C) 7 feet
D) No minimum height
Answer:
D) No minimum height
Explanation:
NEC 410.10(D) does not specify a minimum mounting height for wall-mounted luminaires above a bathroom sink, as long as they are outside the bathtub or shower zone.
3. What is the maximum wattage allowed for an incandescent luminaire installed in a clothes closet?
A) 60 watts
B) 100 watts
C) 150 watts
D) Not permitted
Answer:
D) Not permitted
Explanation:
NEC 410.16(B) prohibits incandescent luminaires with open or partially enclosed lamps in clothes closets due to fire hazards.
4. What is the minimum size copper conductor for a 15-amp household dishwasher circuit?
A) #14 AWG
B) #12 AWG
C) #10 AWG
D) #8 AWG
Answer:
A) #14 AWG
Explanation:
NEC 422.10(A) and Table 310.16 allow a #14 AWG copper conductor for a 15-amp household dishwasher circuit, rated at 15 amps at 75°C.
5. What is the required overcurrent protection for a 240-volt, 20-amp fixed electric space heater?
A) 15 amps
B) 20 amps
C) 25 amps
D) 30 amps
Answer:
B) 20 amps
Explanation:
NEC 424.3(B) requires the branch circuit for a fixed electric space heater to be protected at not more than the circuit rating, which is 20 amps for a 20-amp heater.
6. What is the minimum distance a receptacle must be from a kitchen sink in a dwelling unit?
A) 6 inches
B) 12 inches
C) 18 inches
D) No minimum distance
Answer:
D) No minimum distance
Explanation:
NEC 210.52(C) does not specify a minimum distance for receptacles from a kitchen sink, as long as they meet spacing and GFCI requirements.
7. What is the maximum height for a switch controlling a luminaire in a dwelling unit?
A) 5 feet
B) 6 feet
C) 6 feet 7 inches
D) 7 feet
Answer:
C) 6 feet 7 inches
Explanation:
NEC 404.8(A) specifies that switches, including those controlling luminaires, must not exceed 6 feet 7 inches in height for accessibility.
8. What is the minimum size copper conductor for a 30-amp water heater circuit?
A) #12 AWG
B) #10 AWG
C) #8 AWG
D) #6 AWG
Answer:
B) #10 AWG
Explanation:
NEC 422.13 and Table 310.16 require a minimum #10 AWG copper conductor for a 30-amp water heater circuit, rated at 30 amps at 75°C.
9. What is the required clearance for a luminaire installed above a bathtub?
A) 3 feet horizontally and 8 feet vertically
B) 2 feet horizontally and 6 feet vertically
C) 4 feet horizontally and 7 feet vertically
D) Not permitted
Answer:
A) 3 feet horizontally and 8 feet vertically
Explanation:
NEC 410.10(D) requires luminaires above a bathtub to be at least 3 feet horizontally and 8 feet vertically from the tub’s rim to prevent shock hazards.
10. What is the minimum size copper equipment grounding conductor for a 40-amp appliance circuit?
A) #14 AWG
B) #12 AWG
C) #10 AWG
D) #8 AWG
Answer:
C) #10 AWG
Explanation:
NEC Table 250.122 requires a #10 AWG copper equipment grounding conductor for a 40-amp appliance circuit to ensure effective fault current protection.
11. What is the maximum continuous load permitted on a 20-amp branch circuit supplying a fixed appliance?
A) 12 amps
B) 16 amps
C) 20 amps
D) 24 amps
Answer:
B) 16 amps
Explanation:
NEC 210.23(A)(2) limits the continuous load on a 20-amp branch circuit to 80% of the circuit rating, which is 16 amps (0.8 × 20).
12. What is the required disconnecting means for a 240-volt, 30-amp fixed appliance?
A) A switch within sight
B) A circuit breaker at the panel
C) A disconnect switch within sight or lockable breaker
D) No disconnect required
Answer:
C) A disconnect switch within sight or lockable breaker
Explanation:
NEC 422.31(B) requires a disconnecting means for a fixed appliance, either a switch within sight or a lockable circuit breaker, to ensure safe maintenance.
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Quiz 3: General Electrical Knowledge
1. What is the NEC definition of a 'qualified person'?
A) A person with a master electrician license
B) A person trained and knowledgeable in equipment operation and hazards
C) A person certified by a local authority
D) A person with at least 5 years of experience
Answer:
B) A person trained and knowledgeable in equipment operation and hazards
Explanation:
NEC Article 100 defines a qualified person as one who has the skills, knowledge, and training related to the operation and safety hazards of electrical equipment.
2. What is the minimum working clearance in front of a 480-volt panelboard with exposed live parts on one side?
A) 3 feet
B) 3.5 feet
C) 4 feet
D) 5 feet
Answer:
C) 4 feet
Explanation:
NEC Table 110.26(A)(1) requires a minimum working clearance of 4 feet for equipment rated 151–600 volts with exposed live parts on one side (Condition 2).
3. What is the maximum number of disconnects allowed for a single electrical service?
A) 2
B) 4
C) 6
D) 8
Answer:
C) 6
Explanation:
NEC 230.71(A) permits a maximum of six service disconnects for a single electrical service to ensure safe and manageable control.
4. What is the minimum height for a service drop conductor above a pedestrian-only area?
A) 8 feet
B) 10 feet
C) 12 feet
D) 15 feet
Answer:
B) 10 feet
Explanation:
NEC 230.24(B)(1) requires service drop conductors above pedestrian-only areas to have a minimum clearance of 10 feet for safety.
5. What is the demand factor for the first 3000 VA of a dwelling unit’s general lighting load?
A) 35%
B) 50%
C) 75%
D) 100%
Answer:
D) 100%
Explanation:
NEC Table 220.42 specifies a 100% demand factor for the first 3000 VA of a dwelling unit’s general lighting load in load calculations.
6. What is the maximum voltage drop allowed for a feeder circuit per NEC recommendations?
A) 2%
B) 3%
C) 5%
D) 7%
Answer:
B) 3%
Explanation:
NEC 215.2(A)(4) Informational Note recommends a maximum voltage drop of 3% for feeder circuits to ensure efficient operation.
7. What is the minimum size copper equipment grounding conductor for a 60-amp circuit?
A) #14 AWG
B) #12 AWG
C) #10 AWG
D) #8 AWG
Answer:
C) #10 AWG
Explanation:
NEC Table 250.122 requires a #10 AWG copper equipment grounding conductor for circuits rated up to 60 amps.
8. What is the purpose of a ground-fault circuit-interrupter (GFCI)?
A) To protect equipment from overcurrent
B) To protect against voltage surges
C) To protect persons from electric shock
D) To balance circuit loads
Answer:
C) To protect persons from electric shock
Explanation:
NEC 210.8 explains that GFCI devices are designed to protect persons from electric shock by interrupting the circuit when a ground fault is detected.
9. What is the minimum size of a junction box for a straight pull with two 2-inch conduits?
A) 8 inches
B) 12 inches
C) 16 inches
D) 20 inches
Answer:
C) 16 inches
Explanation:
NEC 314.28(A)(1) requires a junction box for a straight pull to be at least 8 times the trade size of the largest conduit, so 8 × 2 inches = 16 inches.
10. What is the maximum rating for a circuit breaker used as a main disconnect for a 120/240-volt single-phase service?
A) 100 amps
B) 200 amps
C) 400 amps
D) No limit
Answer:
D) No limit
Explanation:
NEC 230.79 does not impose a maximum rating for a circuit breaker used as a service disconnect, as long as it is sized appropriately for the load.
11. What is the minimum size copper neutral conductor for a 100-amp service?
A) #8 AWG
B) #6 AWG
C) #4 AWG
D) #2 AWG
Answer:
B) #6 AWG
Explanation:
NEC 220.61 and Table 310.16 require a #6 AWG copper neutral conductor for a 100-amp service, assuming the neutral carries only unbalanced current.
12. What is the minimum depth for an underground service lateral in a residential area?
A) 12 inches
B) 18 inches
C) 24 inches
D) 36 inches
Answer:
C) 24 inches
Explanation:
NEC Table 300.5 requires a minimum cover of 24 inches for underground service laterals in residential areas to protect against physical damage.
13. What is the maximum length of a flexible cord used for a pendant light fixture?
A) 3 feet
B) 6 feet
C) 10 feet
D) No limit
Answer:
D) No limit
Explanation:
NEC 400.12 does not specify a maximum length for flexible cords used for pendant light fixtures, provided they are properly supported and protected.
14. What is the minimum size copper conductor for a 20-amp branch circuit?
A) #14 AWG
B) #12 AWG
C) #10 AWG
D) #8 AWG
Answer:
B) #12 AWG
Explanation:
NEC 210.19(A)(1) and Table 310.16 require a minimum #12 AWG copper conductor for a 20-amp branch circuit to handle the load safely.
15. What is the maximum number of conductors allowed in a 4-inch square box with a depth of 1.5 inches?
A) 6
B) 9
C) 12
D) 15
Answer:
B) 9
Explanation:
NEC Table 314.16(A) specifies that a 4-inch square box with 1.5-inch depth has a volume of 21 cubic inches, allowing 9 #12 AWG conductors (2.25 cu in each).
16. What is the minimum size of a raceway for a single 1/0 AWG THHN conductor?
A) 3/4 inch
B) 1 inch
C) 1.25 inches
D) 1.5 inches
Answer:
B) 1 inch
Explanation:
NEC Chapter 9 Table 5 and Table 4 require a 1-inch EMT raceway for a single 1/0 AWG THHN conductor, based on a cross-sectional area of 0.1855 sq in and 40% fill.
17. What is the maximum overcurrent protection for a 15-amp receptacle on a 20-amp branch circuit?
A) 15 amps
B) 20 amps
C) 30 amps
D) 40 amps
Answer:
B) 20 amps
Explanation:
NEC 210.21(B)(3) allows a 15-amp receptacle on a 20-amp branch circuit, with the circuit’s overcurrent protection not exceeding 20 amps.
18. What is the minimum size copper conductor for a 240-volt, 30-amp dryer circuit?
A) #12 AWG
B) #10 AWG
C) #8 AWG
D) #6 AWG
Answer:
B) #10 AWG
Explanation:
NEC 210.19(A)(1) and Table 310.16 require a minimum #10 AWG copper conductor for a 30-amp, 240-volt dryer circuit, rated at 30 amps at 75°C.
19. What is the minimum number of 20-amp branch circuits required for a 1500 sq ft dwelling unit?
A) 1
B) 2
C) 3
D) 4
Answer:
B) 2
Explanation:
NEC 210.11(C)(1) requires at least two 20-amp small-appliance branch circuits for a dwelling unit, regardless of size, to serve kitchen and dining areas.
20. What is the maximum height for a receptacle outlet above a kitchen countertop?
A) 12 inches
B) 18 inches
C) 20 inches
D) 24 inches
Answer:
C) 20 inches
Explanation:
NEC 210.52(C)(5) permits receptacle outlets above kitchen countertops to be installed up to 20 inches above the countertop surface.
21. What is the minimum size copper grounding electrode conductor for a ground rod with a 200-amp service?
A) #8 AWG
B) #6 AWG
C) #4 AWG
D) #2 AWG
Answer:
B) #6 AWG
Explanation:
NEC Table 250.66 requires a #6 AWG copper grounding electrode conductor for a ground rod with a 200-amp service, based on the service-entrance conductor size.
22. What is the maximum distance between supports for a Type MC cable?
A) 4.5 feet
B) 6 feet
C) 8 feet
D) 10 feet
Answer:
B) 6 feet
Explanation:
NEC 330.30(B) requires Type MC cable to be supported at intervals not exceeding 6 feet to ensure mechanical stability.
23. What is the minimum size copper conductor for a 40-amp range circuit?
A) #10 AWG
B) #8 AWG
C) #6 AWG
D) #4 AWG
Answer:
B) #8 AWG
Explanation:
NEC 210.19(A)(1) and Table 310.16 require a minimum #8 AWG copper conductor for a 40-amp range circuit, rated at 40 amps at 75°C.
24. What is the maximum number of 15-amp receptacles allowed on a 15-amp branch circuit?
A) 6
B) 8
C) 10
D) No limit
Answer:
D) No limit
Explanation:
NEC 210.21(B) does not limit the number of 15-amp receptacles on a 15-amp branch circuit, as long as the total load does not exceed the circuit capacity.
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Quiz 4: Communication Systems
1. What is the minimum clearance required for a communications cable above a residential driveway?
A) 8 feet
B) 10 feet
C) 12 feet
D) 15.5 feet
Answer:
B) 10 feet
Explanation:
NEC 800.44(A)(2) requires communications cables above a residential driveway to have a minimum clearance of 10 feet to ensure safe vehicle passage.
2. What is the maximum voltage permitted for a network-powered broadband communications system in a dwelling unit?
A) 50 volts
B) 125 volts
C) 150 volts
D) 300 volts
Answer:
B) 125 volts
Explanation:
NEC 830.40 limits network-powered broadband communications systems to a maximum of 125 volts to ground in dwelling units to minimize shock hazards.
3. What type of cable is required for a communications circuit installed in a plenum space?
A) Type CM
B) Type CMR
C) Type CMP
D) Type CMX
Answer:
C) Type CMP
Explanation:
NEC 800.179(A) requires Type CMP (communications plenum) cables for installation in plenum spaces due to their low-smoke and fire-resistant properties.
4. What is the minimum separation distance between a communications cable and a power conductor in a raceway?
A) No separation required
B) 2 inches
C) 6 inches
D) Separate raceways required
Answer:
D) Separate raceways required
Explanation:
NEC 800.133(A)(2) prohibits communications cables from being installed in the same raceway as power conductors, requiring separate raceways to prevent interference.
5. What is the maximum length of an unlisted communications cable permitted to extend into a building from the point of entrance?
A) 25 feet
B) 50 feet
C) 75 feet
D) 100 feet
Answer:
B) 50 feet
Explanation:
NEC 800.90(B) allows unlisted communications cables to extend up to 50 feet from the point of entrance into a building, provided they are terminated in a listed enclosure or device.
6. For a radio and television receiving antenna, what is the minimum size of the grounding conductor?
A) #14 AWG
B) #12 AWG
C) #10 AWG
D) #8 AWG
Answer:
C) #10 AWG
Explanation:
NEC 810.21(J) requires a minimum #10 AWG copper grounding conductor for radio and television receiving antennas to ensure effective grounding.
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Quiz 5: Wiring & Protection
1. What is the minimum size of a neutral conductor for a 125-amp feeder?
A) #6 AWG
B) #4 AWG
C) #2 AWG
D) #1 AWG
Answer:
C) #2 AWG
Explanation:
NEC 215.2(B)(1) and Table 310.16 require the neutral conductor to be sized based on the calculated load but not smaller than the grounding electrode conductor per Table 250.66, which specifies #2 AWG copper for a 125-amp feeder.
2. What is the minimum length of a free conductor at a terminal?
A) 4 inches
B) 6 inches
C) 8 inches
D) 10 inches
Answer:
B) 6 inches
Explanation:
NEC 300.14 requires at least 6 inches of free conductor length at each outlet, junction, or switch point for splices or terminations.
3. What is the maximum ampere rating for a single-pole circuit breaker in a dwelling unit panelboard?
A) 50 amps
B) 60 amps
C) 70 amps
D) 100 amps
Answer:
A) 50 amps
Explanation:
NEC 408.36(D) limits single-pole circuit breakers in dwelling unit panelboards to a maximum of 50 amps to ensure safe operation.
4. What is the minimum size of a conductor for a 100-amp branch circuit?
A) #4 AWG
B) #3 AWG
C) #2 AWG
D) #1 AWG
Answer:
B) #3 AWG
Explanation:
NEC Table 310.16 specifies #3 AWG copper for a 100-amp branch circuit at 75°C terminal rating.
5. What is the minimum width of working space in front of a panelboard rated 600 volts or less?
A) 24 inches
B) 30 inches
C) 36 inches
D) 42 inches
Answer:
B) 30 inches
Explanation:
NEC 110.26(A)(1) requires a minimum working space width of 30 inches in front of a panelboard rated 600 volts or less.
6. What is the minimum size of a grounding electrode conductor for a concrete-encased electrode?
A) #8 AWG
B) #6 AWG
C) #4 AWG
D) #2 AWG
Answer:
C) #4 AWG
Explanation:
NEC 250.52(A)(3) requires a minimum #4 AWG copper conductor for a concrete-encased electrode (Ufer ground).
7. What is the minimum size of a main bonding jumper for a 400-amp service?
A) #2 AWG
B) #1 AWG
C) #1/0 AWG
D) #2/0 AWG
Answer:
C) #1/0 AWG
Explanation:
NEC Table 250.102(C)(1) specifies a #1/0 AWG copper main bonding jumper for a 400-amp service.
8. What is the minimum height for a service drop above a commercial parking lot?
A) 12 feet
B) 15 feet
C) 18 feet
D) 22 feet
Answer:
C) 18 feet
Explanation:
NEC 230.24(B)(4) requires a minimum clearance of 18 feet for service conductors above areas subject to truck traffic, such as commercial parking lots.
9. What is the minimum size of a feeder conductor for a 250-amp service?
A) #1/0 AWG
B) #2/0 AWG
C) 3/0 AWG
D) 4/0 AWG
Answer:
D) 4/0 AWG
Explanation:
NEC Table 310.16 specifies 4/0 AWG copper for a 250-amp feeder at 75°C terminal rating.
10. What is the maximum number of conductors in a single raceway without derating?
A) 3
B) 4
C) 6
D) 9
Answer:
A) 3
Explanation:
NEC 310.15(B)(3)(a) requires ampacity adjustment (derating) for more than three current-carrying conductors in a raceway or cable.
11. What is the minimum size of a grounding electrode conductor for a ground rod?
A) #8 AWG
B) #6 AWG
C) #4 AWG
D) #2 AWG
Answer:
B) #6 AWG
Explanation:
NEC 250.66(A) specifies a minimum #6 AWG copper grounding electrode conductor for a ground rod.
12. What is the minimum depth for underground service conductors under a residential driveway?
A) 12 inches
B) 18 inches
C) 24 inches
D) 30 inches
Answer:
C) 24 inches
Explanation:
NEC Table 300.5 requires a minimum burial depth of 24 inches for underground service conductors under residential driveways.
13. What is the maximum rating for a circuit breaker protecting a multi-outlet branch circuit supplying receptacles?
A) 20 amps
B) 30 amps
C) 40 amps
D) 50 amps
Answer:
D) 50 amps
Explanation:
NEC 210.23(C) permits multi-outlet branch circuits supplying receptacles to be protected by circuit breakers up to 50 amps.
14. What is the minimum size of a conductor for a 70-amp branch circuit?
A) #6 AWG
B) #5 AWG
C) #4 AWG
D) #3 AWG
Answer:
C) #4 AWG
Explanation:
NEC Table 310.16 specifies #4 AWG copper for a 70-amp branch circuit at 75°C terminal rating.
15. What is the minimum size of a supply-side bonding jumper for a 300-amp service?
A) #4 AWG
B) #2 AWG
C) #1/0 AWG
D) #2/0 AWG
Answer:
B) #2 AWG
Explanation:
NEC Table 250.102(C)(1) specifies a #2 AWG copper supply-side bonding jumper for a 300-amp service.
16. What is the minimum volume for a 4 x 4 x 2-1/8 inch square box?
A) 21 cubic inches
B) 30.3 cubic inches
C) 34 cubic inches
D) 42 cubic inches
Answer:
B) 30.3 cubic inches
Explanation:
NEC Table 314.16(A) lists the volume of a 4 x 4 x 2-1/8 inch square box as 30.3 cubic inches for box fill calculations.
17. What is the minimum clearance for service conductors above a pedestrian walkway?
A) 8 feet
B) 10 feet
C) 12 feet
D) 15 feet
Answer:
B) 10 feet
Explanation:
NEC 230.24(B)(1) requires a minimum clearance of 10 feet for service conductors above pedestrian walkways.
18. What is the minimum size of a conductor for an 80-amp branch circuit?
A) #6 AWG
B) #4 AWG
C) #3 AWG
D) #2 AWG
Answer:
C) #3 AWG
Explanation:
NEC Table 310.16 specifies #3 AWG copper for an 80-amp branch circuit at 75°C terminal rating.
19. What is the minimum size of an equipment grounding conductor for a 100-amp circuit?
A) #10 AWG
B) #8 AWG
C) #6 AWG
D) #4 AWG
Answer:
B) #8 AWG
Explanation:
NEC Table 250.122 requires a #8 AWG copper equipment grounding conductor for a 100-amp circuit.
20. What is the minimum depth for nonmetallic raceways under a residential lawn?
A) 6 inches
B) 12 inches
C) 18 inches
D) 24 inches
Answer:
C) 18 inches
Explanation:
NEC Table 300.5 requires a minimum burial depth of 18 inches for nonmetallic raceways under residential lawns.
21. What is the maximum number of 90-degree bends allowed in a single conduit run?
A) 2
B) 3
C) 4
D) 5
Answer:
C) 4
Explanation:
NEC 358.26 limits a single conduit run to no more than four 90-degree bends (360 degrees total) to facilitate conductor pulling.
22. What is the minimum size of a feeder conductor for a 150-amp service?
A) #2 AWG
B) #1 AWG
C) #1/0 AWG
D) #2/0 AWG
Answer:
C) #1/0 AWG
Explanation:
NEC Table 310.15(B)(7) permits #1/0 AWG copper for a 150-amp feeder in a dwelling unit.
23. What is the minimum size of a pull box for an angle pull with 3-inch conduits?
A) 18 inches
B) 24 inches
C) 30 inches
D) 36 inches
Answer:
B) 24 inches
Explanation:
NEC 314.28(A)(2) requires a minimum distance of 6 times the largest conduit trade size plus the sum of other conduit sizes for an angle pull: 6 x 3 = 18 inches, plus 3 inches = 21 inches, rounded to 24 inches.
24. What is the minimum size of a grounding electrode conductor for a 500 kcmil service conductor?
A) #2 AWG
B) #1/0 AWG
C) #2/0 AWG
D) #3/0 AWG
Answer:
C) #2/0 AWG
Explanation:
NEC Table 250.66 specifies a #2/0 AWG copper grounding electrode conductor for service conductors up to 500 kcmil copper.
25. What is the minimum distance between a service panel and a water pipe?
A) 0 inches
B) 6 inches
C) 12 inches
D) 18 inches
Answer:
A) 0 inches
Explanation:
NEC 110.26 does not require a minimum distance between a service panel and a water pipe, provided the pipe is bonded per 250.104.
26. What is the minimum size of a conductor for a 90-amp branch circuit?
A) #4 AWG
B) #3 AWG
C) #2 AWG
D) #1 AWG
Answer:
B) #3 AWG
Explanation:
NEC Table 310.16 specifies #3 AWG copper for a 90-amp branch circuit at 75°C terminal rating.
27. What is the minimum size of a bonding jumper for a metal water piping system in a 200-amp service?
A) #8 AWG
B) #6 AWG
C) #4 AWG
D) #2 AWG
Answer:
C) #4 AWG
Explanation:
NEC Table 250.102(C)(1) specifies a #4 AWG copper bonding jumper for a 200-amp service to bond metal water piping.
28. What is the minimum size of a feeder tap conductor for a 25-foot tap from a 400-amp feeder?
A) #6 AWG
B) #4 AWG
C) #2 AWG
D) #1/0 AWG
Answer:
C) #2 AWG
Explanation:
NEC 240.21(B)(2) requires a feeder tap conductor to have an ampacity not less than 1/3 of the feeder rating: 400 A / 3 ≈ 133 A, requiring #2 AWG copper per Table 310.16 at 75°C.
29. What is the minimum size of a conductor for a 110-amp branch circuit?
A) #2 AWG
B) #1 AWG
C) #1/0 AWG
D) #2/0 AWG
Answer:
B) #1 AWG
Explanation:
NEC Table 310.16 specifies #1 AWG copper for a 110-amp branch circuit at 75°C terminal rating.
30. What is the minimum distance between a receptacle and a gas fireplace in a dwelling unit?
A) 6 inches
B) 12 inches
C) 18 inches
D) 24 inches
Answer:
A) 6 inches
Explanation:
NEC 210.52(A)(3) requires receptacles to be installed per general spacing rules, but manufacturer instructions typically mandate a minimum of 6 inches from a gas fireplace for safety.
31. What is the minimum size of a conductor for a 120-amp branch circuit?
A) #2 AWG
B) #1 AWG
C) #1/0 AWG
D) #2/0 AWG
Answer:
B) #1 AWG
Explanation:
NEC Table 310.16 specifies #1 AWG copper for a 120-amp branch circuit at 75°C terminal rating.
32. What is the minimum size of a grounding electrode conductor for a 350 kcmil service conductor?
A) #2 AWG
B) #1/0 AWG
C) #2/0 AWG
D) #3/0 AWG
Answer:
B) #1/0 AWG
Explanation:
NEC Table 250.66 specifies a #1/0 AWG copper grounding electrode conductor for service conductors up to 350 kcmil copper.
33. What is the minimum size of a conductor for a 130-amp branch circuit?
A) #1 AWG
B) #1/0 AWG
C) #2/0 AWG
D) #3/0 AWG
Answer:
B) #1/0 AWG
Explanation:
NEC Table 310.16 specifies #1/0 AWG copper for a 130-amp branch circuit at 75°C terminal rating.
34. What is the minimum size of a feeder conductor for a 350-amp service?
A) 250 kcmil
B) 300 kcmil
C) 350 kcmil
D) 400 kcmil
Answer:
C) 350 kcmil
Explanation:
NEC Table 310.16 specifies 350 kcmil copper for a 350-amp feeder at 75°C terminal rating.
35. What is the minimum size of an equipment grounding conductor for a 200-amp circuit?
A) #8 AWG
B) #6 AWG
C) #4 AWG
D) #2 AWG
Answer:
B) #6 AWG
Explanation:
NEC Table 250.122 requires a #6 AWG copper equipment grounding conductor for a 200-amp circuit.
36. What is the minimum size of a conductor for a 140-amp branch circuit?
A) #1/0 AWG
B) #2/0 AWG
C) #3/0 AWG
D) 4/0 AWG
Answer:
B) #2/0 AWG
Explanation:
NEC Table 310.16 specifies #2/0 AWG copper for a 140-amp branch circuit at 75°C terminal rating.
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Quiz 6: Special Equipment
1. What is the minimum clearance required above a swimming pool for overhead power lines operating at 240 volts?
A) 14.5 feet
B) 22.5 feet
C) 25 feet
D) 27 feet
Answer:
B) 22.5 feet
Explanation:
NEC 680.8(A) and Table 680.8 require a minimum clearance of 22.5 feet for overhead power lines up to 750 volts above a swimming pool to ensure safety.
2. What is the minimum disconnecting means required for a neon sign operating at 1000 volts?
A) A single-pole switch
B) A double-pole switch
C) A disconnect switch within sight
D) No disconnect required
Answer:
C) A disconnect switch within sight
Explanation:
NEC 600.6(A) mandates a disconnect switch within sight of each electric sign operating over 1000 volts to ensure safe maintenance.
3. What is the minimum bonding conductor size for metal parts of a permanently installed swimming pool?
A) #12 AWG
B) #10 AWG
C) #8 AWG
D) #6 AWG
Answer:
C) #8 AWG
Explanation:
NEC 680.26(B)(7) requires a minimum #8 AWG solid copper bonding conductor for metal parts of a permanently installed swimming pool to ensure equipotential bonding.
4. What is the maximum voltage permitted for underwater luminaires in a fountain without GFCI protection?
A) 15 volts
B) 30 volts
C) 120 volts
D) 150 volts
Answer:
A) 15 volts
Explanation:
NEC 680.51(E) limits underwater luminaires in fountains to 15 volts or less without GFCI protection to minimize shock hazards.
5. What is the minimum distance from a photovoltaic (PV) array to a grounded metal object for systems operating at 600 volts?
A) 0 inches
B) 6 inches
C) 12 inches
D) 18 inches
Answer:
A) 0 inches
Explanation:
NEC 690.43 does not require a minimum distance between a PV array and a grounded metal object, provided the array is properly grounded and bonded.
6. What is the minimum height for a disconnect switch for a crane in an industrial facility?
A) 4 feet
B) 5 feet
C) 6 feet
D) 6 feet 7 inches
Answer:
D) 6 feet 7 inches
Explanation:
NEC 610.32 requires the disconnecting means for a crane to be accessible and not exceed 6 feet 7 inches in height, consistent with NEC 404.8(A).
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Quiz 7: Motors & Controls
1. What is the minimum size of branch-circuit conductors for a 10-hp, 230-volt, single-phase motor?
A) #12 AWG
B) #10 AWG
C) #8 AWG
D) #6 AWG
Answer:
B) #10 AWG
Explanation:
NEC Table 430.248 lists the full-load current for a 10-hp, 230-volt, single-phase motor as 50 amps. NEC 430.22 requires conductors to be sized at 125% of the full-load current: 50 A × 1.25 = 62.5 A. Per Table 310.16, #10 AWG copper at 75°C is rated for 65 amps, which is sufficient.
2. What is the maximum rating of the branch-circuit short-circuit and ground-fault protective device for a 5-hp, 460-volt, three-phase motor?
A) 30 amps
B) 40 amps
C) 50 amps
D) 70 amps
Answer:
B) 40 amps
Explanation:
NEC Table 430.250 lists the full-load current for a 5-hp, 460-volt, three-phase motor as 7.6 amps. NEC Table 430.52 allows a maximum inverse time circuit breaker rating of 250% of the full-load current: 7.6 A × 2.5 = 19 A. The next standard breaker size per 240.6(A) is 20 amps, but for practical application, 40 amps is often the maximum allowed to protect the motor circuit.
3. What is the minimum size of the equipment grounding conductor for a motor circuit with a 60-amp branch-circuit protective device?
A) #12 AWG
B) #10 AWG
C) #8 AWG
D) #6 AWG
Answer:
B) #10 AWG
Explanation:
NEC Table 250.122 specifies that for a circuit with a 60-amp overcurrent protective device, the minimum equipment grounding conductor size is #10 AWG copper.
4. What is the minimum disconnecting means required for a motor controller rated at 25 horsepower?
A) A non-fusible switch rated at 60 amps
B) A fusible switch rated at 100 amps
C) A circuit breaker rated at 125 amps
D) A molded case switch rated at 200 amps
Answer:
C) A circuit breaker rated at 125 amps
Explanation:
NEC 430.109 requires the disconnecting means to be rated at least 115% of the motor’s full-load current. For a 25-hp, 460-volt, three-phase motor, Table 430.250 gives 34 amps. Then, 34 A × 1.15 = 39.1 A. NEC 430.110(C) requires the disconnect to handle the locked-rotor current, which for a 25-hp motor is approximately 6 times the full-load current (204 A). A 125-amp circuit breaker is sufficient.
5. What is the maximum overload protection setting for a 7.5-hp, 208-volt, three-phase motor with a nameplate full-load current of 25 amps?
A) 25 amps
B) 31.25 amps
C) 35 amps
D) 40 amps
Answer:
B) 31.25 amps
Explanation:
NEC 430.32(A)(1) requires overload protection for a motor to be set at 125% of the nameplate full-load current for motors with a service factor of 1.15 or greater: 25 A × 1.25 = 31.25 A.
6. What is the minimum size of feeder conductors supplying two 15-hp, 460-volt, three-phase motors?
A) #10 AWG
B) #8 AWG
C) #6 AWG
D) #4 AWG
Answer:
C) #6 AWG
Explanation:
NEC Table 430.250 lists the full-load current for a 15-hp, 460-volt, three-phase motor as 21 amps. For two motors, the total is 42 amps. NEC 430.24 requires feeder conductors to be sized at 125% of the largest motor’s full-load current plus 100% of the other motor’s: (21 A × 1.25) + 21 A = 26.25 A + 21 A = 47.25 A. Per Table 310.16, #6 AWG copper at 75°C is rated for 65 amps, which is sufficient.
7. What is the minimum rating of a motor controller for a 20-hp, 230-volt, single-phase motor?
A) 50 amps
B) 75 amps
C) 100 amps
D) 125 amps
Answer:
C) 100 amps
Explanation:
NEC Table 430.248 lists the full-load current for a 20-hp, 230-volt, single-phase motor as 96 amps. NEC 430.83 requires the controller to be rated not less than the motor’s full-load current. A 100-amp controller is the minimum standard rating per 430.83(A).
8. What is the maximum distance allowed between a motor and its controller for a 10-hp motor in an industrial setting?
A) 25 feet
B) 50 feet
C) 75 feet
D) No limit
Answer:
D) No limit
Explanation:
NEC 430.102(B) requires the motor controller disconnect to be within sight (50 feet or less, per 100.8) unless lockable and readily accessible. However, the controller itself has no specific distance limit from the motor, provided wiring and protection requirements are met.
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Quiz 8: Plan Reading
1. On an electrical plan, what does the symbol 'S3' typically represent?
A) Single-pole switch
B) Three-way switch
C) Dimmer switch
D) Four-way switch
Answer:
B) Three-way switch
Explanation:
Per NEC 404.9 and standard electrical plan symbols (referenced in NFPA 170), 'S3' denotes a three-way switch, used to control a light fixture from two locations.
2. A plan specifies a 200-amp service for a single-family dwelling. What is the minimum size of the service-entrance conductors?
A) #2 AWG
B) #1/0 AWG
C) #2/0 AWG
D) 4/0 AWG
Answer:
C) #2/0 AWG
Explanation:
NEC Table 310.15(B)(7) allows #2/0 AWG copper conductors for a 200-amp service in a single-family dwelling, based on the load calculation and 75°C terminal rating.
3. An electrical plan shows a 'G' symbol near a receptacle. What does this indicate?
A) General-purpose receptacle
B) Ground-fault circuit-interrupter (GFCI) receptacle
C) Grounded receptacle
D) Generator-powered receptacle
Answer:
B) Ground-fault circuit-interrupter (GFCI) receptacle
Explanation:
Per NEC 406.4 and standard plan symbols, a 'G' near a receptacle symbol indicates a GFCI-protected receptacle, required in areas like bathrooms or kitchens per NEC 210.8.
4. A plan specifies a 120/240-volt, single-phase panelboard with a 100-amp main breaker. What is the minimum size of the grounding electrode conductor?
A) #8 AWG
B) #6 AWG
C) #4 AWG
D) #2 AWG
Answer:
B) #6 AWG
Explanation:
NEC Table 250.66 specifies a #6 AWG copper grounding electrode conductor for service-entrance conductors up to #2/0 AWG copper, which corresponds to a 100-amp service.
5. On a plan, what does the notation 'EMT' indicate for a conduit run?
A) Electrical metallic tubing
B) Extra metallic tubing
C) Encased metal tubing
D) Embedded metallic tubing
Answer:
A) Electrical metallic tubing
Explanation:
NEC Article 358 defines 'EMT' as electrical metallic tubing, a common conduit type used for protecting and routing electrical conductors, as indicated on electrical plans.
6. A plan shows a lighting fixture with the symbol 'EF'. What does this typically represent?
A) Emergency lighting fixture
B) Exterior floodlight
C) Energy-efficient fixture
D) Exit sign fixture
Answer:
A) Emergency lighting fixture
Explanation:
Per NEC 700.16 and standard plan symbols, 'EF' denotes an emergency lighting fixture, typically connected to a backup power source for egress lighting.
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Quiz 9: Special Conditions
1. What is the maximum time allowed for an emergency system to transfer power to critical loads after a power failure?
A) 10 seconds
B) 30 seconds
C) 60 seconds
D) 120 seconds
Answer:
A) 10 seconds
Explanation:
NEC 700.12(A) requires emergency systems to supply power to critical loads within 10 seconds of a power failure to ensure life safety.
2. What is the minimum battery capacity required for emergency lighting in a building with a 90-minute duration requirement?
A) 60 minutes
B) 90 minutes
C) 120 minutes
D) 180 minutes
Answer:
B) 90 minutes
Explanation:
NEC 700.12(F) mandates that battery systems for emergency lighting provide power for at least 90 minutes, matching the minimum duration required for egress lighting.
3. For a legally required standby system, what is the maximum time allowed to restore power to connected loads?
A) 10 seconds
B) 30 seconds
C) 60 seconds
D) 90 seconds
Answer:
C) 60 seconds
Explanation:
NEC 701.12(A) requires legally required standby systems to restore power within 60 seconds to support essential functions like fire protection systems.
4. What is the minimum separation required between emergency system wiring and non-emergency wiring in a raceway?
A) No separation required
B) 2 inches
C) 6 inches
D) Separate raceways required
Answer:
D) Separate raceways required
Explanation:
NEC 700.10(B) mandates that emergency system wiring be kept entirely separate from non-emergency wiring, typically in separate raceways or enclosures, to prevent interference.
5. For an optional standby system powering a commercial building, what is the minimum overcurrent protection required for a 50-amp load?
A) 40 amps
B) 50 amps
C) 60 amps
D) 70 amps
Answer:
B) 50 amps
Explanation:
NEC 702.10 requires overcurrent protection for optional standby systems to be sized not less than the load, which is 50 amps in this case, per NEC 240.4.
6. What is the maximum voltage allowed for an energy storage system (ESS) battery circuit in a dwelling unit?
A) 50 volts
B) 100 volts
C) 150 volts
D) 600 volts
Answer:
B) 100 volts
Explanation:
NEC 706.15(A) limits energy storage system battery circuits in dwelling units to a maximum of 100 volts to reduce shock hazards, unless specifically permitted otherwise.
7. What is the minimum conductor size for a 30-amp emergency circuit supplying exit signs?
A) #14 AWG
B) #12 AWG
C) #10 AWG
D) #8 AWG
Answer:
B) #12 AWG
Explanation:
NEC 700.10(D) and 215.2(A)(1) require conductors for emergency circuits to be sized for the load, with a 30-amp circuit requiring #12 AWG copper per Table 310.16 at 75°C (rated for 30 amps).
8. For interconnected power production sources, what is the maximum percentage of the busbar rating that the sum of all supply breakers can contribute?
A) 100%
B) 120%
C) 125%
D) 150%
Answer:
B) 120%
Explanation:
NEC 705.12(B)(2)(3) allows the sum of all breakers supplying a busbar, including interconnected power sources (e.g., solar), to not exceed 120% of the busbar rating to ensure safe operation.
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Quiz 10: Special Occupancies
1. What is the minimum sealing requirement for conduit entering a Class I, Division 1 hazardous location?
A) No seal required
B) Seal within 10 feet of the boundary
C) Seal within 18 inches of the boundary
D) Seal at the boundary
Answer:
D) Seal at the boundary
Explanation:
NEC 501.15(A)(4) requires conduit seals to be installed at the boundary of a Class I, Division 1 hazardous location to prevent the passage of gases or vapors.
2. In a hospital patient care area, what is the minimum number of receptacles required for a general care bed location?
A) 2
B) 4
C) 6
D) 8
Answer:
B) 4
Explanation:
NEC 517.18(B) mandates a minimum of four receptacles for each general care patient bed location in a hospital to support medical equipment and patient needs.
3. What is the maximum height allowed for a disconnect switch in a motion picture studio soundstage?
A) 6 feet
B) 6 feet 7 inches
C) 7 feet
D) 8 feet
Answer:
B) 6 feet 7 inches
Explanation:
NEC 530.14 and 404.8(A) require disconnect switches, including those in motion picture studios, to be installed at a maximum height of 6 feet 7 inches for accessibility.
4. In an assembly occupancy with over 1000 persons, what is the minimum number of exits required for a main floor seating area?
A) 1
B) 2
C) 3
D) 4
Answer:
C) 3
Explanation:
NEC 518.4(B), referencing NFPA 101 (Life Safety Code), requires a minimum of three exits for assembly occupancies with over 1000 persons to ensure safe egress.
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