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30 Bonding of Internal Parts
30.1 General
30.1.1 An exposed dead metal part that is likely to become energized by an electrical fault shall be
reliably bonded to the point of connection of the field-equipment-grounding means.
Exception: A dead metal part of a low-voltage component need not be bonded if it is:
a) Positively separated from line-voltage parts and wiring; or
b) Separated from live parts and wiring by an interposing barrier or part in such a manner that
the interposed barrier or part will be the first to be subjected to an electrical fault. A metal
barrier or part shall be grounded or bonded to the point of connection of the field equipment-
grounding means.
30.1.1 revised October 15, 2004
30.1.2 An uninsulated metal part, such as a baffle, a barrier, a cover, an enclosure guard, a transformer
core, or the like, shall be electrically bonded together if they might be contacted by the user or serviceman.
30.1.3 With reference to 30.1.2, internal parts that are painted or otherwise coated prior to assembly shall
be secured in position by a fastening means that will reliably penetrate the surface coating.
30.1.3.1 The grounding connection and the output neutral of an inverter that is intended to be connected
to the cigarette lighter outlet of a vehicle shall be bonded to the inverter frame or enclosure. See 12.2.1.
30.1.3.1 revised October 15, 2004
30.1.4 Uninsulated live parts and wiring shall be separated from a moving or movable part, such as a
relay or contactor magnet and armature, by clamping, positioning, or an equivalent means that will
maintain permanent separation.
30.1.5 A metal part, such as an adhesive-attached metal marking plate, a screw, a handle, or the like,
that is located on the outside of an enclosure or cabinet, need not be bonded if it is isolated from electrical
components and wiring by a grounded metal part so that it is not likely to become energized, or separated
from wiring and spaced from uninsulated live parts as if it were a grounded part. Other parts not required
to be bonded are:
a) Small internal assembly screws, rivets, or other small fasteners;
b) A handle for a disconnect switch; and
c) A relay or contactor magnet and armature.
OCTOBER 15, 2004 UL 458 44A
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