408.40 Grounding of Panelboards. Panelboard cabinets
and panelboard frames, if of metal, shall be in physical
contact with each other and shall be connected to an equip-
ment grounding conductor. Where the panelboard is used
with nonmetallic raceway or cable or where separate equip-
ment grounding conductors are provided, a terminal bar for
the equipment grounding conductors shall be secured inside
the cabinet. The terminal bar shall be bonded to the cabinet
and panelboard frame, if of metal; otherwise it shall be
connected to the equipment grounding conductor that is run
with the conductors feeding the panelboard.
Exception: Where an isolated equipment grounding con-
ductor is provided as permitted by 250.146(D), the insu-
lated equipment grounding conductor that is run with the
circuit conductors shall be permitted to pass through the
panelboard without being connected to the panelboard?s
equipment grounding terminal bar.
Equipment grounding conductors shall not be connected
to a terminal bar provided for grounded conductors or neutral
conductors unless the bar is identified for the purpose and is
located where interconnection between equipment grounding
conductors and grounded circuit conductors is permitted or
required by Article 250.