main bonding jumper

wyboy

Senior Member
We have been having this debate for a while. In a main breaker, service rated panel used as the service disconnect, we used the green screw used to bond the equipment enclosure to the neutral bar and there is a separate ground bar attached to the can. NEC 250.24 (B) requires the grounded conductor to be connected to the equipment grounds and the equipment enclosure by an unsliced main bonding jumper. Does the enclosure count as part of the main bonding jumper or do I need to run a number 4 (for a 200 amp service) between the ground bar and the neutral bar.
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
The screw is all that's required you just cannot land neutrals on the EGC bus and use the enclosure as a pathway for the neutral current.
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
Rob:
I agree 100%, but I can't find the Code section that permits the EGC to connect to the enclosure. I attempted to fins it in answering the OP. Can you direct me ?
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
Maybe this section:

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.
 
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