CSLB C-10 Electrical ContractorEquipment and InstallationEasy
An electrician is installing a 200-ampere, 120/240-volt single-phase panelboard in a retail store. The panelboard is against a wall, and there are no live parts on the opposite side. What is the minimum depth of working space required in front of this panelboard?
- A48 inches
- B30 inches
- C60 inches
- D36 inches
Show answer & explanationAnswer & explanation
Correct answer: D. 36 inches
According to NEC 110.26(A)(1), for equipment operating at 0-150 volts to ground, where there are no live parts on the opposite side of the working space and the wall is concrete, brick, or tile (Condition 1), the minimum depth of working space required is 3 feet (36 inches).
Why the other options are wrong
- A. This depth would be required for Condition 2 (0-150V to ground, live parts opposite) or Condition 1 (151-600V to ground).
- B. This is the minimum width of the working space, not the depth.
- C. This depth would be required for Condition 3 (0-150V to ground) or higher voltage conditions.
Electrical Working Space Depth
The minimum clear distance required in front of electrical equipment to ensure safe operation, maintenance, and access for personnel.
- Governed by NEC 110.26(A)(1).
- Depth varies based on voltage to ground and conditions on the opposite side.
- Ensures worker safety from arc flash and shock hazards.
Memory trick: Work Smart, Stay Apart.