What is the minimum wire bending space at the top and bottom of a panelboard that has one 3/0 conductor connected to each busbar in the panelboard?

• A. 7 in
• B. 7 1/2 in
• C. 8 in
• D. 6 1/2 in

Answer: (D)

The key idea here is the space required to route and bend large feeder conductors into a panelboard without crowding or damaging insulation. For a panelboard where the largest conductor size connected to each busbar is 3/0, the NEC specifies a minimum bending space of 6 1/2 inches at each end (top and bottom). That amount provides enough room to form the bends and get the conductors into the busbar lugs while maintaining required clearances. So, 6 1/2 inches is the correct minimum per end for this configuration.