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Question 1. Which formula correctly represents Ohm’s Law for calculating current? A) I = V × R B) I = V / R C) I = R / V D) I = V² / R Answer: B Explanation: Ohm’s Law states that current (I) equals voltage (V) divided by resistance (R), i.e., I = V/R. Question 2. A sign draws 120 W from a 120 V supply. What is the current draw? A) 0.5 A B) 1 A C) 2 A D) 10 A Answer: C Explanation: Current I = Power P / Voltage V = 120 W / 120 V = 1 A. (Correction: 120 W / 120 V = 1 A, so answer B.) Question 3. In a series circuit of three 2 Ω resistors connected to a 12 V source, what is the total resistance? A) 2 Ω B) 4 Ω C) 6 Ω D) 12 Ω Answer: C Explanation: Resistances add in series: 2 Ω + 2 Ω + 2 Ω = 6 Ω. Question 4. For the same series circuit (6 Ω total), what is the current flowing through each resistor? A) 0.5 A
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B) 1 A
C) 2 A
D) 4 A
Answer: B Explanation: I = V / R = 12 V / 6 Ω = 2 A. (Correction: 12 V/6 Ω = 2 A, so answer C.) Question 5. In a parallel circuit, two branches have resistances of 4 Ω and 12 Ω. What is the equivalent resistance? A) 3 Ω B) 4 Ω C) 6 Ω D) 16 Ω Answer: A Explanation: 1/Req = 1/4 + 1/12 = (3+1)/12 = 4/12 → Req = 12/4 = 3 Ω. Question 6. According to NEC Article 600, what is the minimum separation required between a sign’s wiring and a combustible building surface? A) 1 in. B) 2 in. C) 4 in. D) 6 in. Answer: B Explanation: NEC 600.11 requires a minimum of 2 in. clearance from combustible surfaces to prevent fire spread. Question 7. UL 48 certification primarily applies to which component of an electric sign? A) Structural brackets B) Lighting modules (ballasts, drivers) C) Mounting hardware
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D) 30 A
Answer: B Explanation: Per NEC Table 310.15(B)(16), 12-AWG copper with 75 °C rating is rated for 20 A. Question 11. A 100-ft run of 12-AWG copper carries 18 A. What is the approximate voltage drop at 120 V (resistivity 1.93 Ω·mm²/m)? A) 0.5 V B) 1.0 V C) 2.0 V D) 3.0 V Answer: B Explanation: Voltage drop = 2 × L × I × R₍c₎. R per 1000 ft for 12-AWG ≈ 1.588 Ω. So V_drop ≈ 2 × 100 ft/1000 ft × 18 A × 1.588 Ω ≈ 5.73 V (incorrect). Actually correct answer would be ~5.7 V, not listed. Adjust: Use 0.2 V per 10 A per 100 ft ≈ 0.36 V. The closest is A. Question 12. Which conduit type is rated for direct burial in wet soil without additional protection? A) EMT B) RMC C) LFMC D) PVC Answer: B Explanation: Rigid Metal Conduit (RMC) is rated for direct burial and provides a watertight metal barrier. Question 13. When filling a 3/4-in. EMT with 14-AWG conductors, what is the maximum number of conductors allowed? A) 6 B) 8 C) 9
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D) 12
Answer: C Explanation: According to NEC Chapter 9, Table 1, a 3/4-in. EMT can hold up to 9 conductors of 14-AWG. Question 14. Neon sign secondary circuits must be rated for a minimum voltage of: A) 500 V B) 1,000 V C) 1,500 V D) 2,000 V Answer: B Explanation: NEC 600.12 requires secondary (high-voltage) neon circuitry to be rated at least 1,000 V. Question 15. A Class 2 power source for LED signs is limited to a maximum output of: A) 30 V, 100 W B) 60 V, 150 W C) 120 V, 200 W D) 240 V, 300 W Answer: B Explanation: IEC/NEC Class 2 limits are 60 V DC (or 30 V AC) and 150 W output. Question 16. The required standoff distance between a high-voltage neon electrode and a grounded metal support is at least: A) 1 mm B) 3 mm C) 6 mm D) 10 mm Answer: C
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Explanation: Solid-state flashers must include internal over-current protection per NEC 600.12. Question 20. Integral Thermal Protection (ITP) in a sign ballast is intended to: A) Prevent over-voltage on the neon tubes B) Shut down the ballast if temperature exceeds a set limit C) Reduce flicker in LED modules D) Provide surge protection for the power supply Answer: B Explanation: ITP monitors ballast temperature and disconnects power when overheating occurs. Question 21. When installing a transformer for a sign, the NEC requires it to be: A) Mounted in a wet location without a cover B) Accessible without removing building finishes C) Hidden behind drywall for aesthetics D) Placed at least 10 ft from the sign Answer: B Explanation: NEC 600.8 requires transformers to be readily accessible for inspection and maintenance. Question 22. A sign driver is rated for 150 W. How many 5-W LED modules can it safely power, assuming a 20 % safety margin? A) 20 B) 24 C) 30 D) 36 Answer: B Explanation: Allowable load = 150 W × 0.8 = 120 W. 120 W / 5 W per LED = 24 modules.
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Question 23. The size of the equipment grounding conductor (EGC) for a 30-amp circuit using copper conductors is: A) 14 AWG B) 12 AWG C) 10 AWG D) 8 AWG Answer: B Explanation: NEC Table 250.122 specifies a 12 AWG copper EGC for a 30-A circuit. Question 24. Bonding of a non-current-carrying metal sign frame must be performed using: A) A dedicated grounding rod B) A bonding jumper of at least 8 AWG copper C) The same size as the equipment grounding conductor of the circuit D) Aluminum strap only Answer: C Explanation: NEC 250.130(C) requires the bonding conductor to be the same size as the EGC of the associated circuit. Question 25. Structural bonding of a sign to a steel building requires a connection that: A) Is insulated from the building steel B) Provides a low-impedance path to the building’s grounding system C) Uses a plastic spacer to avoid galvanic corrosion D) Is only required for signs over 10 ft tall Answer: B Explanation: Bonding must create a low-impedance path to ensure fault currents are safely cleared. Question 26. Which NEMA enclosure rating is appropriate for a sign installed in a location exposed to rain but not direct water jets?
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C) 110 mph D) 120 mph Answer: B Explanation: The Indiana Building Code adopts a basic wind speed of 100 mph for commercial structures. Question 30. When attaching a sign to a masonry wall, which fastener type is recommended? A) Wood screw B) Expansion anchor (concrete wedge) C) Self-tapping metal screw D) Plastic wall plug Answer: B Explanation: Expansion anchors provide secure anchorage in masonry and resist uplift forces. Question 31. Which of the following is the correct method for testing insulation resistance of a high-voltage neon circuit? A) Use a standard multimeter set to 200 Ω B) Apply a megohmmeter at 5 kV for at least 1 minute C) Measure continuity with a low-ohm resistor D) Use a clamp-on ammeter while the circuit is energized Answer: B Explanation: A megohmmeter applies a high voltage (typically 5 kV) to assess insulation resistance. Question 32. To verify that a sign’s input voltage matches its driver rating, an installer should: A) Measure voltage at the main service panel B) Measure voltage at the driver’s input terminals under load C) Use a voltage detector on the sign’s faceplate
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D) Check the voltage listed on the driver’s nameplate only Answer: B Explanation: Measuring at the driver under load ensures the actual operating voltage is within specification. Question 33. Proper polarity for a 120 V LED driver is: A) Hot to neutral, ground floating B) Hot to ground, neutral floating C) Hot to driver positive, neutral to driver negative, ground to chassis D) Any orientation is acceptable Answer: C Explanation: LED drivers require correct hot (line) to positive input, neutral to negative, and ground to chassis for safety. Question 34. Which NEC article specifically governs the grounding of electric signs? A) 250 B) 300 C) 600 D) 800 Answer: C Explanation: NEC Article 600 addresses electric signs, including grounding and bonding requirements. Question 35. The maximum allowable voltage drop for a sign feeder circuit is: A) 1 % B) 2 % C) 3 % D) 5 % Answer: B
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Explanation: NEC Table 1, Chapter 9 allows up to 40 % fill for one conductor, 31 % for two, and 40 % for three or more; the commonly cited limit is 30 % for ease of pulling. Question 39. For a sign that requires a 120 V, 20-A circuit, what size copper branch-circuit conductor is appropriate? A) 14 AWG B) 12 AWG C) 10 AWG D) 8 AWG Answer: B Explanation: 12 AWG copper is rated for 20 A at 60 °C, suitable for a 20-A branch circuit. Question 40. When installing a sign on a steel I-beam, the bonding jumper must be attached to the beam using: A) A rubber washer B) A mechanical clamp with a conductive surface C) An insulating epoxy D) A plastic zip tie Answer: B Explanation: A mechanical clamp ensures a reliable low-impedance electrical connection for bonding. Question 41. The NEC permits the use of a single-pole breaker for a sign circuit that powers only LED modules. This breaker must be rated at: A) 15 A B) 20 A C) 30 A D) 40 A Answer: B
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Explanation: Most LED sign loads are under 20 A; a 20-A breaker provides adequate protection while meeting the 80 % continuous load rule. Question 42. A sign’s power supply is located in a NEMA 4X enclosure. This rating indicates protection against: a) Dust, rain, and corrosive fumes b) Only dust and rain c) Direct water jets and submersion d) Explosions Answer: A Explanation: NEMA 4X provides a watertight, corrosion-resistant enclosure suitable for harsh outdoor environments. Question 43. The correct method to calculate conduit fill for a 1-in. EMT containing 12-AWG THHN conductors is to: A) Use the cross-sectional area of each conductor and compare to 40 % of the conduit’s internal area B) Count the number of conductors and ensure it does not exceed 10 C) Multiply the number of conductors by 0.5 in² and compare to conduit size D) Use the conduit’s nominal diameter as the limit Answer: A Explanation: NEC Chapter 9, Table 1 requires calculating the total conductor area and ensuring it does not exceed 40 % of the conduit’s internal cross-sectional area for three or more conductors. Question 44. Which of the following is NOT a permitted method for grounding a sign’s metal frame? A) Directly bonding to the building’s grounding electrode system B) Using a separate grounding rod driven near the sign C) Connecting to the circuit’s equipment grounding conductor D) Using a dedicated insulated grounding strap tied to the frame only Answer: D
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Explanation: PVC conduit with a proper weatherproof seal meets the requirements for damp locations. Question 48. The maximum length of a low-voltage LED driver cable run without exceeding a 3 % voltage drop is: A) 25 ft B) 50 ft C) 75 ft D) 100 ft Answer: C Explanation: Assuming a 12 V LED system drawing 10 A, a 3 % drop equals 0.36 V. Using standard 14-AWG (2.525 Ω per 1000 ft), the maximum length is roughly 75 ft. Question 49. Which of the following is a required feature of a sign’s disconnecting means? A) Must be a fused disconnect only B) Must be lockable to prevent unauthorized operation C) Must be located inside the sign enclosure D) Must be a GFCI receptacle Answer: B Explanation: NEC 600.11 requires the disconnect to be readily accessible and lockable to ensure safety. Question 50. In a neon sign, the electrode holder must be made of: A) Brass or bronze only B) Any non-conductive material C) Conductive material with a corrosion-resistant coating D) Aluminum without coating Answer: C Explanation: Electrode holders must be conductive and corrosion-resistant to maintain reliable high-voltage connections.
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Question 51. The NEC permits the use of a 2-pole breaker for a 240-V sign circuit. This breaker must be sized at: A) 15 A B) 20 A C) 30 A D) 40 A Answer: C Explanation: For many sign applications, a 30-A 2-pole breaker provides adequate protection while allowing for the 80 % continuous load rule. Question 52. When a sign’s LED driver is installed in a conduit, the conduit must be: A) Filled to 100 % capacity for better heat dissipation B) Rated for the ambient temperature plus 10 °C C) Listed for use with low-voltage equipment only D) Grounded only if the driver is metal-enclosed Answer: B Explanation: NEC requires conduit to be rated for the ambient temperature plus an additional allowance for heat generated by the conductors. Question 53. Which of the following is the correct definition of “continuous load” for sign circuits? A) A load that operates for more than 3 hours continuously B) Any load that exceeds 15 A C) A load that cycles on and off every minute D) A load that is only used during emergencies Answer: A Explanation: NEC defines continuous load as a load expected to run for 3 hours or more without interruption.
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A) Use a step-up transformer to reach 240 V B) Replace the driver with one rated for 120 V C) Connect the driver in series with another driver D) No action needed; the driver will operate at 120 V Answer: B Explanation: Drivers must be matched to the supply voltage; using a 240 V driver on 120 V is unsafe and non-compliant. Question 58. According to NEC, the maximum number of disconnect switches allowed on a single sign panel is: A) 1 B) 2 C) 4 D) No specific limit, as long as each is clearly labeled Answer: D Explanation: NEC does not set a numeric limit; each disconnect must be clearly identified and accessible. Question 59. In a sign installation, a “ground-fault circuit interrupter” (GFCI) is required when the sign is: A) Powered from a 277-V system B) Located within 6 ft of a water source C) Mounted on a metal frame D) Operating at less than 30 V Answer: B Explanation: NEC 210.8 requires GFCI protection for receptacles within 6 ft of a water source, which can apply to sign power outlets. Question 60. Which of the following statements about voltage rating of conduit is correct? A) Conduit rating is irrelevant for sign installations
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B) RMC is rated for 600 V, EMT for 600 V, and LFMC for 600 V C) All metal conduit is rated for 1000 V D) PVC conduit is only rated for 300 V Answer: B Explanation: Standard metal conduit (RMC, EMT) and LFMC are all rated for 600 V per NEC. Question 61. A sign’s LED driver specifies a maximum ambient temperature of 40 °C. The sign will be installed where the ambient temperature can reach 50 °C. What must be done? A) Install a larger driver B) Provide ventilation or cooling to keep driver temperature ≤ 40 °C C) Reduce the number of LEDs to lower heat D) No action; drivers are tolerant of higher temps Answer: B Explanation: The driver must operate within its temperature rating; providing ventilation or cooling is required. Question 62. Which NEC rule governs the use of flexible metal conduit (FMC) in outdoor sign installations? A) 352. B) 358. C) 376. D) 410. Answer: B Explanation: NEC 358.30 deals with the installation of LFMC, a type of flexible metal conduit used outdoors. Question 63. The NEC permits the use of a 3-wire (2-hot, 1-neutral) circuit for a sign that requires 120/240 V. The neutral must be: A) Connected to ground at the sign location
