Box Grounding

[Will Wire]

A metal luminaire is grounded by the circuit's equipment grounding conductor and then the luminaire is attached to a metal box with screws. Is the box now grounded according to code or does the box have to be grounded independently of the luminaire? Thanks, Trent.

 

[infinity]

Independently. Take a look at 250.148(B):

250.148 Continuity and Attachment of Equipment
Grounding Conductors to Boxes. Where circuit conduc-
tors are spliced within a box, or terminated on equipment
within or supported by a box, any equipment grounding con-
ductor(s) associated with those circuit conductors shall be con-
nected within the box or to the box with devices suitable for
the use in accordance with 250.148(A) through (E).
Exception: The equipment grounding conductor permitted
in 250.146(D) shall not be required to be connected to the
other equipment grounding conductors or to the box.
(A) Connections. Connections and splices shall be made
in accordance with 110.14(B) except that insulation shall
not be required.
(B) Grounding Continuity. The arrangement of ground-
ing connections shall be such that the disconnection or the
removal of a receptacle, luminaire, or other device fed from
the box does not interfere with or interrupt the grounding
continuity.

 

[Ponchik]

Always connect the equipment grounding conductor to the box first then to the device, fixture,..... etc.