Are the Square D thermal units UL Listed or Recognized?
NEMA style Overload Relays and Accessories
They are not formally Listed or Recognized by UL nor are they formally Certified by CSA. Rather, they are considered by those agencies simply component parts of certified equipment in which they are intended to be used.
Although UL has not technically Listed/Recognized these thermal units, UL has produced a descriptive Report that covers basic thermal unit construction. For persons interested, that Report is documented in UL File E78351, Volume 2C, Section 1, issued 02/06/81.
Unlike UL, CSA has not produced documentation specifically dedicated to thermal units. In most cases, when mentioning thermal units in equipment Certification Reports, CSA simply refers to either the above UL document for thermal units, or to a UL Report that covers the same equipment as being covered by CSA. If it is necessary to respond to a customer`s inquiry for CSA information on these thermal units, it is recommended that one simply refer the customer to the CSA File and Class of Certified equipment that uses the thermal unit in question.