To ensure that no uninsulated, ungrounded service busbar or service terminal is exposed to inadvertent contact by persons or maintenance equipment while servicing load terminations [408.3(A)(2)].
Generally, no except for the required interconnections and control wiring [408.3(A)(3)]. But you can run conductors horizontally through that section if they are insulated from busbars by a barrier [408.3(A)(3) Exception].
- A main bonding jumper [408.3(C)] or the equivalent. Make sure you size it per 250.28(D). Note there is an exception for high-impedance grounded neutral systems.
- It has to be A, B, C from front to back, top to bottom, or left to right, as viewed from the front of the switchboard, switchgear, or panelboard [408.3(E)(1)]. On 3-phase, 4-wire delta systems, the B phase is the one with the highest voltage.