The following changes in requirements to the Standard for Power Conversion Equipment, UL
508C, are being proposed for preliminary review and comment only:
1. For Preliminary Review Only: Modification of Short-Circuit Testing Requirements
2. For Preliminary Review Only: Clarification of Control Circuit Transformer Protection
Requirements
3. For Preliminary Review Only: Revision of Ratings for Capacitors in AC Circuits
4. For Preliminary Review Only: Revision of Marking and Instruction Requirements to
Use Appropriate Signal Words
5. For Preliminary Review Only: Addition of Cheesecloth as a Fire Indicator
6. For Preliminary Review Only: Revision of Frequency Requirements for Dielectric
Voltage Withstand Testing
7. For Preliminary Review Only: Revision of Breakdown of Components Testing in
Secondary Circuits
8. For Preliminary Review Only: Revision of Table 63.1 to Include Marking Requirements
in 56.6 and 56.7.
UL 508C BULLETIN-2011 history
2018UL 508C BULLETIN-2018 UL Standard for Safety Power Conversion Equipment (COMMENTS DUE: April 16@ 2018)
2013UL 508C CRD-2013 UL Standard for Safety Power Conversion Equipment - Section/Paragraph Reference: New Section - Service Equipment Use Subject: Drives to be used in the service entrance section of installation (Edition 3: May 03, 2002)
2012UL 508C CRD-2012 UL Standard for Safety Power Conversion Equipment - Section/Paragraph Reference: 56.7 Subject: Marking requirements for drives complying with 20.1.11 b) or c) (Edition 3: May 03@ 2002)
2010UL 508C CRD-2010 UL Standard for Safety Power Conversion Equipment - Section/Paragraph Reference: New Section 69 Subject: Modular Drive System Requirements (Edition 3: May 03@ 2002)
2010UL 508C BULLETIN-2010 UL Standard for Safety Power Conversion Equipment (COMMENTS DUE: March 29@ 2010)
2009UL 508C BULLETIN-2009 UL Standard for Safety Power Conversion Equipment (COMMENTS DUE: NOVEMBER 16@ 2009)