501.30 Grounding and Bonding, Class I, Divisions 1
and 2. Wiring and equipment in Class I, Division 1 and 2
locations shall be grounded as specified in Article 250 and
in accordance with the requirements of 501.30(A) and (B).
(A) Bonding. The locknut-bushing and double-locknut types
of contacts shall not be depended on for bonding purposes, but
bonding jumpers with proper fittings or other approved means
of bonding shall be used. Such means of bonding shall apply
to all intervening raceways, fittings, boxes, enclosures, and so
forth between Class I locations and the point of grounding for
service equipment or point of grounding of a separately derived
system.
Exception: The specific bonding means shall be required
only to the nearest point where the grounded circuit conductor
and the grounding electrode are connected together
on the line side of the building or structure disconnecting
means as specified in 250.32(B), provided the branchcircuit
overcurrent protection is located on the load side of
the disconnecting means.
Informational Note: See 250.100 for additional bonding
requirements in hazardous (classified) locations.
(B) Types of Equipment Grounding Conductors. Flexible
metal conduit and liquidtight flexible metal conduit
shall include an equipment bonding jumper of the wire type
in compliance with 250.102.
Exception: In Class I, Division 2 locations, the bonding
jumper shall be permitted to be deleted where all of the
following conditions are met:
(1) Listed liquidtight flexible metal conduit 1.8 m (6 ft) or
less in length, with fittings listed for grounding, is used.
(2) Overcurrent protection in the circuit is limited to 10
amperes or less.
(3) The load is not a power utilization load