Download PrepIQ District Of Columbia DC Journeyman Sign Electrician338 Ultimate Exam and more Exams Technology in PDF only on Docsity!
Journeyman Sign Electrician338 Ultimate
Exam
Question 1. Which NEC article primarily governs the installation of sign wiring? A) Article 210 B) Article 250 C) Article 590 D) Article 720 Answer: C Explanation: Article 590 of the NEC specifically addresses the requirements for electric signs and outline lighting. Question 2. The minimum conduit fill for a single 3/4-in. EMT conduit with three #12 AWG conductors is: A) 20 % B) 35 % C) 40 % D) 53 % Answer: B Explanation: For more than two conductors, the maximum conduit fill is 40 % of the internal area; however, for a single conduit the recommended practice is to stay at 35 % to allow easy pulling. Question 3. A sign that uses neon tubes must have which type of grounding electrode? A) Ground rod only B) Grounding electrode conductor to a metal water pipe C) Both a ground rod and a grounding electrode conductor to the service grounding bus D) No grounding required if the sign is low voltage Answer: C Explanation: Neon signs are considered high-voltage luminaires and must be grounded to the building’s grounding electrode system per NEC 250.52(A)(3).
Journeyman Sign Electrician338 Ultimate
Exam
Question 4. The maximum allowable voltage drop for a sign circuit supplying a total load of 5 A over 100 ft is: A) 2 % B) 3 % C) 5 % D) 10 % Answer: B Explanation: NEC recommends a maximum of 3 % voltage drop for feeder circuits to ensure proper operation of signs. Question 5. When installing a sign on a metal pole, the attachment must be protected against corrosion by: A) Using only stainless-steel fasteners B) Applying a zinc-rich primer to the pole C) Installing a non-conductive gasket between the sign and the pole D) All of the above Answer: D Explanation: All methods are acceptable ways to prevent galvanic corrosion between dissimilar metals. Question 6. Which of the following is the correct rating for a transformer used to step down 277 V to 120 V for a small illuminated sign? A) 5 VA B) 15 VA C) 30 VA D) 60 VA Answer: B Explanation: Small sign loads typically require a transformer of at least 15 VA to handle inrush currents and continuous operation.
Journeyman Sign Electrician338 Ultimate
Exam
Question 10. A sign that uses LED modules rated at 120 V must be installed with which type of over-current protection? A) 15-A standard circuit breaker B) 20-A standard circuit breaker C) 30-A standard circuit breaker D) No over-current protection required Answer: B Explanation: LED modules typically draw less than 10 A; a 20-A breaker provides adequate protection while complying with NEC 240.4(D). Question 11. The purpose of a “sign grounding electrode” is to: A) Reduce electromagnetic interference (EMI) B) Provide a low-impedance path for fault current C) Prevent lightning damage only D) All of the above Answer: B Explanation: Grounding electrodes provide a safe path for fault currents, protecting both equipment and personnel. Question 12. Which of the following is NOT permitted as a support for a hanging sign? A) Suspended chains attached to a structural roof beam B) Concrete anchor bolts embedded in a slab C) Wood studs without metal plates D) Steel brackets bolted to a load-bearing wall Answer: C Explanation: Wood studs alone lack the required strength and fire-rating for supporting signs; metal reinforcement is required.
Journeyman Sign Electrician338 Ultimate
Exam
Question 13. The maximum height for a sign that does not require a permit in Washington, DC is: A) 12 ft B) 18 ft C) 24 ft D) 30 ft Answer: B Explanation: DC Municipal Regulations allow signs up to 18 ft without a permit, provided they meet all other code requirements. Question 14. When a sign is powered from a separate panel, the feeder must be protected by a: A) GFCI receptacle at the sign location B) Circuit breaker sized for the feeder load only C) Two-pole breaker if the sign is 240 V D) Both B and C Answer: D Explanation: A feeder for a 240-V sign requires a two-pole breaker sized for the load, and the breaker provides over-current protection. Question 15. A sign that includes a built-in audio system must meet which NEC requirement? A) Install a dedicated grounding conductor for the audio equipment B) Use shielded cable for audio signals only C) Provide a separate disconnecting means for the audio load D) No additional requirements beyond the sign wiring Answer: C Explanation: NEC 720.8 requires a separate disconnect for audio/video equipment to ensure safe isolation.
Journeyman Sign Electrician338 Ultimate
Exam
Question 19. The minimum burial depth for a PVC conduit protecting a sign’s feeder in a residential driveway is: A) 6 in. B) 12 in. C) 18 in. D) 24 in. Answer: B Explanation: NEC 300.5 requires a minimum of 12 in. burial for PVC conduit under a driveway. Question 20. When a sign includes a high-intensity discharge (HID) lamp, the required ballast must be: A) Listed for the specific lamp type B) Rated for at least 150 % of lamp wattage C) Installed in a weatherproof enclosure if outdoors D) All of the above Answer: D Explanation: All three conditions ensure safe, code-compliant operation of HID lamps. Question 21. The NEC permits the use of flexible metal conduit (FMC) for sign wiring in which of the following locations? A) Inside a hollow metal sign frame B) Exposed outdoors without a raceway cover C) In a conduit run longer than 30 ft D) None of the above Answer: A Explanation: FMC can be used within the interior of a sign frame where it is protected from physical damage.
Journeyman Sign Electrician338 Ultimate
Exam
Question 22. A sign that is powered by a solar photovoltaic (PV) system must meet which additional requirement? A) The PV array must be grounded per NEC 690. B) The sign must have a battery backup of at least 2 hours C) The PV system must be listed for sign applications only D) No additional requirements beyond standard sign wiring Answer: A Explanation: All PV systems must be properly grounded to protect against fault currents and lightning. Question 23. The NEC classification for a sign that is permanently attached to a building’s façade is: A) Class I, Division 2 B) Class II, Division 1 C) Class III, Division 1 D) Class IV, Division 2 Answer: A Explanation: Permanent signs are considered Class I, Division 2 hazardous (low voltage) circuits. Question 24. Which of the following is the correct method for bonding a metal sign support to the grounding system? A) Use a bonding jumper no smaller than 6 AWG copper B) Use a 12 AWG aluminum bonding strap C) Rely on the conduit for bonding only D) No bonding required if the sign is low voltage Answer: A Explanation: NEC 250.102 requires a bonding jumper sized according to Table 250.122; 6 AWG copper is typical for sign installations.
Journeyman Sign Electrician338 Ultimate
Exam
Question 28. Which of the following is a permitted method for supporting a suspended “floating” sign? A) Steel cables anchored to a concrete anchor with a minimum 200-lb tensile capacity B) Wooden rods attached to the sign frame only C) Plastic ties rated for 50 lb load D) None of the above Answer: A Explanation: Steel cables with adequate tensile strength and proper anchorage are acceptable for suspended signs. Question 29. The required labeling for a sign feeder circuit in the electrical panel must include: A) The sign’s address only B) The circuit amperage and “SIGN” designation C) The sign manufacturer’s name D) No label is required if the circuit is dedicated Answer: B Explanation: NEC 210.7 requires clear identification of the circuit’s purpose and rating. Question 30. For a sign that uses a 24-V DC power supply, the maximum allowable voltage drop across the feeder conductors is: A) 1 % B) 2 % C) 3 % D) 5 % Answer: B Explanation: Low-voltage DC circuits are limited to a 2 % voltage drop to maintain proper illumination levels.
Journeyman Sign Electrician338 Ultimate
Exam
Question 31. The NEC requires a disconnecting means for a sign that is: A) Over 150 sq ft in area B) Powered by more than one circuit C) Mounted on a roof D) All of the above Answer: D Explanation: Any sign meeting any of those criteria must have a readily accessible disconnect. Question 32. When a sign is installed on a historic building, the electrical work must also comply with: A) The National Historic Preservation Act (NHPA) B) The Americans with Disabilities Act (ADA) C) Local historic preservation ordinances in addition to NEC D) None of the above Answer: C Explanation: Historic preservation guidelines often impose additional constraints beyond the NEC. Question 33. The appropriate conduit type for a sign that will be exposed to direct sunlight and UV radiation is: A) Rigid metal conduit (RMC) only B) PVC conduit with UV-stabilized jacket C) EMT without any coating D) Flexible metal conduit (FMC) Answer: B Explanation: UV-stabilized PVC maintains its integrity under prolonged sunlight exposure.
Journeyman Sign Electrician338 Ultimate
Exam
Question 37. The minimum height for a “hand-illuminated” sign to be considered a “readable sign” by the DC code is: A) 24 in. above ground B) 36 in. above ground C) 48 in. above ground D) 60 in. above ground Answer: B Explanation: DC signage standards define a readable sign as being at least 36 in. above grade. Question 38. When a sign includes a USB charging station for public use, the outlet must be protected by a: A) GFCI receptacle B) AFCI breaker only C) Standard 15-A breaker D) No special protection required Answer: A Explanation: NEC 210.8(A) requires GFCI protection for all outdoor and publicly accessible 125-V, 15- or 20-A receptacles. Question 39. The required fire-resistance rating for a sign mounted on an exterior fire-rated wall is: A) 1-hour rating B) 2-hour rating C) Same as the wall’s rating D) No rating required because the sign is not a structural element Answer: C Explanation: The sign assembly must not compromise the fire-resistance rating of the wall on which it is mounted.
Journeyman Sign Electrician338 Ultimate
Exam
Question 40. Which of the following is an acceptable method for grounding a metal sign support that is not in direct contact with the earth? A) Driving a ground rod at the base of the sign B) Connecting a grounding electrode conductor to the building’s grounding bus C) Using a ground-fault circuit interrupter in place of a grounding electrode D) None; the sign must be directly earth-grounded Answer: B Explanation: Connecting to the building’s grounding system provides a low-impedance path without requiring a separate ground rod. Question 41. The minimum ampacity of a feeder supplying a 150-W LED sign at 120 V, assuming continuous operation, is: A) 10 A B) 12 A C) 15 A D) 20 A Answer: B Explanation: 150 W/120 V = 1.25 A; applying the 125 % continuous load factor yields 1.56 A, rounded up to the next standard breaker size, which is 12 A. Question 42. In the District of Columbia, a sign that projects more than 10 ft above the roof line must obtain a: A) Building permit only B) Sign permit from the Department of Consumer and Regulatory Affairs (DCRA) C) Electrical permit only D) No permit if the sign is illuminated Answer: B Explanation: DCRA regulates oversized signs and requires a specific sign permit for projections exceeding 10 ft.
Journeyman Sign Electrician338 Ultimate
Exam
Question 46. Which of the following statements about “back-fed” sign circuits is true? A) They are prohibited by NEC 590. B) They are allowed only if the feeder is rated for the total load C) They require a dedicated disconnect at the sign location D) Both B and C are correct Answer: D Explanation: Back-fed circuits must be sized for the total load and have a disconnect at the sign. Question 47. The required minimum size for a conduit that houses three 6 AWG THHN conductors for a 240-V sign is: A) 1/2-in. EMT B) 3/4-in. EMT C) 1-in. EMT D) 1-1/4-in. EMT Answer: B Explanation: Based on conduit fill tables, 3/4-in. EMT can accommodate three 6 AWG conductors with adequate clearance. Question 48. When a sign includes a programmable timer that disables the sign during certain hours, the timer must be installed: A) Inside the sign’s enclosure only B) In a location that is readily accessible for maintenance C) Within 3 ft of the sign’s power source D) No specific location required Answer: B Explanation: NEC 110.3(B) requires that control devices be installed where they can be readily accessed for service.
Journeyman Sign Electrician338 Ultimate
Exam
Question 49. The allowable temperature rise for conductors in a sign’s power supply enclosure is limited to: A) 60 °C above ambient B) 75 °C above ambient C) 90 °C above ambient D) No limit if the enclosure is ventilated Answer: A Explanation: NEC 310.15(B)(2)(a) limits temperature rise to 60 °C for conductors in enclosed spaces unless otherwise permitted. Question 50. For a sign that uses a 240-V three-phase motor to rotate a billboard, the motor must be protected by a: A) Single-pole breaker B) Two-pole breaker C) Three-pole breaker sized according to the motor’s full-load current D) No breaker if the motor has built-in overload protection Answer: C Explanation: Three-phase motors require a three-pole breaker sized for the motor’s full-load current. Question 51. The NEC requires that a sign’s wiring be inspected and approved by: A) The building owner B) The sign manufacturer C) The local authority having jurisdiction (AHJ) D) No inspection required if the sign is low voltage Answer: C Explanation: All electrical installations, including signs, must be inspected by the AHJ.
Journeyman Sign Electrician338 Ultimate
Exam
Question 55. The NEC permits the use of “flexible metal conduit” (FMC) inside a sign frame for voltage levels up to: A) 120 V B) 250 V C) 600 V D) 1000 V Answer: C Explanation: FMC is listed for use up to 600 V, making it suitable for most sign applications. Question 56. A sign that incorporates a video display must be supplied with a dedicated circuit that includes: A) A GFCI breaker B) An AFCI breaker C) Both GFCI and AFCI protection D) No special protection required if the display is low voltage Answer: C Explanation: Video displays can present arc-fault hazards; NEC 210.12(A) requires AFCI protection, and outdoor installations require GFCI. Question 57. The required grounding method for a metal-clad sign mounted on a non-metallic (concrete) wall is: A) Ground rod driven near the sign B) Bonding to the building’s grounding electrode system via a grounding conductor C) No grounding required if the sign is low voltage D) Grounding through the conduit only Answer: B Explanation: The sign must be bonded to the building’s grounding electrode system.
Journeyman Sign Electrician338 Ultimate
Exam
Question 58. When a sign is installed on a roof, the NEC requires a disconnect within: A) 5 ft of the sign B) 10 ft of the sign C) 25 ft of the sign D) No specific distance if the sign is roof-mounted Answer: C Explanation: NEC 590.4 requires a disconnect within 25 ft of the sign for roof-mounted installations. Question 59. The minimum size of a grounding electrode conductor for a sign with a 200 A service is: A) #4 AWG copper B) #2 AWG copper C) #1/0 AWG copper D) #4/0 AWG copper Answer: B Explanation: Table 250.122 specifies #2 AWG copper for a 200-A service. Question 60. Which of the following is a required marking on a sign’s power supply enclosure? A) “Do not open – high voltage” B) Manufacturer’s serial number only C) The sign’s dimensions D) The date of installation Answer: A Explanation: NEC 110.21 requires clear warning labels for high-voltage equipment.
