Mike, I ran into something yesterday that only Explosionproof motors are listed by UL or any other
listing agencies. Maybe you could confirm this for me. Is this true and how do other Inspection departments
handle this issue?
Pat Finney, Tacoma Power, Code Enforcement
UL Lists only Explosionproof Motors and Fire Pump Motors; all others motors are evaluated as a Recognized
Component. Motors are “Recognized” and not “Listed” because they can be used in any number of different
applications. Without knowing the exact application we are not able to List them. Except for
Explosionproof motors and Fire Pump motors, UL must evaluate the motors as part of the end use product
to List the overall product. Only as an end use product can the motor be fully evaluated because
it is loaded as intended in an overall enclosure, for an intended application, where all of the factors
surrounding its use can be fully evaluated.
“Recognized Component” motors are identified by the backwards UR on the motor. This signifies
that it has been evaluated on limited basis, meaning that possibly only the protection (i.e. thermally
or impedance) and/or construction was verified. The rest of the application dependent tests
are conducted in the end use product. Recognized Components are not intended for field installation,
they are intended for factory installation in Listed end products.
I hope this provides you with the information that you are seeking. If I can be of further assistance,
please let me know.
Tom Lichtenstein, Staff Engineer
Regulatory Services, Underwriters Laboratories Inc.