UL1004-1 Rotating Electrical Machines –General Requirements
First Edition – September, 2008
Second Edition -
September 19, 2012
22.1 Material in direct contact with uninsulated live parts other than magnet wire shall be porcelain or
another material investigated and found acceptable in accordance with the requirements covering
mechanical/electrical property considerations of the Standard for Polymeric Materials – Use in Electrical
Equipment Evaluations, UL 746C. These materials shall withstand the most severe conditions likely to be
met in service.
Exception: Small parts and adhesives need not be investigated if they are:
a) Not relied upon to maintain the proper functioning of the device with regard to the likelihood
of electric shock, fire, and injury to persons; and/or
b) Not relied upon to maintain separation between uninsulated live parts of opposite polarity,
live parts, and accessible metal parts and/or uninsulated live parts and earth ground.
22.2 The material of any part of a base or body shall not introduce a risk of fire or shock by warping,
creeping, or distorting under conditions of arcing, temperature, and mechanical stress that are likely to
occur in service.
22.3 Material in contact with live parts other than magnet wire shall comply with Table 22.1 with respect
to resistance to flame propagation, resistance to arc tracking, resistance to ignition from electrical sources,
resistance to moisture absorption, dielectric strength, and mechanical strength. A material shall not
display a loss of these properties beyond the minimum required level as a result of aging.
Exception No. 1: The minimum required CTI (PLC) for rotating machinery that successfully passes the
Dust Test – Outdoor Method as specified in the Standard for Enclosures for Electrical Equipment,
Environmental Considerations, UL 50E, is 4.
Exception No. 2: Small parts and adhesives need not be investigated if they are:
a) Not relied upon to maintain the proper functioning of the device with regard to the likelihood
of electric shock, fire, and injury to persons; and/or
b) Not relied upon to maintain separation between uninsulated live parts of opposite polarity,
live parts, and accessible metal parts and/or uninsulated live parts and earth ground.
Exception No. 3: The application of the provisions of Section 9, Creepage Distances, of the Standard for
Insulation Coordination Including Clearances and Creepage Distances for Electrical Equipment, UL 840,
may be used as an alternative to a material having the CTI (PLC) required by Table 22.1.
Exception No. 4: Commutator insulation material made of phenolic is acceptable with no further testing.
Exception No. 5: Commutator insulation material other than phenolic and having a CTI (PLC) less than
specified in Table 22.1 may be used provided it complies with 37A.1.
22.4 Material used to support live parts or an insulating barrier shall be acceptable for continuous
operation at the maximum temperature measured on the material during the Temperature Test, Section 32.
22.5 A small molded part such as a terminal block shall have mechanical strength and rigidity that
withstands the stresses of actual service.
22.6 A molded part shall not exhibit softening of the material determined by handling immediately after
the condition specified in 33.4, nor shall there be shrinkage, warpage, or other distortions as determined
after cooling to room temperature that results in any of the following:
a) Reduction of spacings between uninsulated live parts of opposite polarity, uninsulated live
parts and accessible dead or grounded metal, and uninsulated live parts and the enclosure
below the minimum acceptable values;
b) Uninsulated live parts or internal wiring accessible to contact, or defeating the integrity of the
enclosure so that acceptable mechanical protection is not afforded to internal parts of the
equipment;
c) Interference with the intended operation or servicing of the equipment.