Journeyman Electrician's Panelboards and Switchboards Flashcards
7 cards from real Journeyman Electrician’s Exam practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Journeyman Electrician's Panelboards and Switchboards flashcards as text
Per NEC 408.7, unused openings in panelboard enclosures must be:
Answer: Effectively closed to afford protection substantially equivalent to the wall of the enclosure
NEC 408.7 requires unused openings in panelboard enclosures to be effectively closed to provide protection equivalent to the wall of the enclosure, preventing contact with live parts.
When installing a panelboard in a wet location, the enclosure must be weatherproof and installed with a minimum air space of how much between the enclosure and the mounting surface per NEC 312.2?
Answer: ¼ inch (6 mm)
NEC 312.2 requires weatherproof enclosures in wet locations to be spaced at least ¼ inch from the mounting surface to prevent moisture accumulation behind the enclosure.
Per NEC 408.36(A), individual main overcurrent protection for a lighting and appliance branch-circuit panelboard is not required when the panelboard feeder has overcurrent protection rated no greater than:
Answer: The panelboard's bus rating
NEC 408.36(A) allows a panelboard without a main breaker (main lug only) if the feeder's overcurrent protection does not exceed the panelboard's bus rating.
Per NEC 110.26(C), at least one entrance not less than 24 inches wide and 6½ feet high is required for rooms containing switchboards or panelboards rated:
Answer: 1200 amperes or more and over 6 feet wide
NEC 110.26(C) requires at least one entrance for electrical rooms containing switchboards or panelboards rated 1200A or more and over 6 feet wide to provide safe egress.
When a panelboard is installed as a sub-panel in a detached garage fed from the main residential panel, the neutral conductor and equipment grounding conductor must be:
Answer: Kept separate and terminated on separate bars within the sub-panel
Per NEC 250.142(B), at sub-panels the neutral and equipment grounding conductors must be kept separate to prevent objectionable current from flowing on grounding conductors.
Per NEC 408.3(C), panelboards and switchboards must be mounted in a vertical position unless the equipment is specifically listed and marked for other orientations. The busbars in a panelboard shall be arranged to:
Answer: Provide phase identification and be plainly marked or color-coded
NEC 408.3(F) requires busbars and wiring to be arranged and field-marked to provide phase identification, enabling safe and accurate connections during installation and maintenance.
Per NEC 240.24(D), overcurrent protective devices shall not be located in the vicinity of easily ignitable material. Which location is specifically prohibited for panelboard installation?
Answer: Clothes closets
NEC 240.24(D) prohibits overcurrent devices from being located in clothes closets because of the proximity to easily ignitable stored materials like clothing.