UL1004-1 Rotating Electrical Machines –General Requirements
First Edition – September, 2008
Second Edition -
September 19, 2012
10.1 Machines exhibiting the following characteristics shall have provision for grounding:
a) A machine for use in damp or wet locations;
b) A machine intended to be field installed and used on a circuit operating at more than 150
volts to ground – see 10.2; or
c) An electric generator.
Exception: A machine may be provided with a double insulation system that complies with the Standard
for Double Insulation Systems for Use in Electrical Equipment, UL 1097, in place of a provision for
grounding.
10.2 With reference to 10.1(b), when the machine is marked to indicate that it is to be connected to a
circuit operating at 150 volts or less to ground, it is not required to comply with this Section.
10.3 A machine marked as being provided with double insulation shall not be provided with a means for
grounding.
10.4 If a grounding means is provided, whether required or not, it shall comply with this Section.
10.5 All exposed dead metal parts and all dead metal parts within the enclosure that are exposed to
contact during any user servicing operation and likely to become energized shall be reliably connected to
the means for grounding.
10.6 A grounding terminal or lead shall be provided for a machine intended to be permanently connected.
10.7 A separable connection, such as that provided by an attachment plug and a mating connector or
receptacle, shall be such that the equipment-grounding connection is made before connection to and
broken after disconnection from the output conductors.
Exception: Interlocked plugs, receptacles, and connectors that are not energized when the
equipment-grounding connection is made or broken are acceptable.
10.8 A terminal solely for the connection of an equipment-grounding conductor shall be capable of
securing a conductor of the size necessary for the application. A connection device that depends on
solder alone shall not be provided for connecting the equipment-grounding conductor.
10.9 A wire-binding screw or pressure wire connector intended for the connection of an
equipment-grounding conductor shall be located so that it is not removed during normal servicing of the
machine.