Ul 508a Standard Pdf 79

What is UL 508A and how does it affect industrial control panels

UL 508A is the Standard for Industrial Control Panels published by UL (Underwriters Laboratories), a global safety certification organization. It provides guidelines for the design, construction, and marking of control panels intended for general industrial use and operating from a voltage of 1000 volts or less.

UL 508A covers industrial control panels that control equipment such as pumps, fans, conveyors, compressors, mixers, and production machines. It also covers industrial control panel enclosures and industrial machinery electrical panels. UL 508A does not cover fire pump controllers, elevator controllers, crane controllers, or marine use panels.

UL 508A is intended to reduce the risk of fire, electric shock, and injury to persons by ensuring that the control panels are properly wired, protected, and labeled. UL 508A also helps to facilitate the inspection of control panels by electrical inspectors and authorities having jurisdiction (AHJs).

The third edition of UL 508A was published on April 24, 2018 and has an effective date of July 1, 2020. It includes new and revised requirements for components, wiring methods, short-circuit current ratings (SCCR), overcurrent protection devices (OCPDs), markings, and documentation.

Some of the key changes in the third edition of UL 508A are:

The introduction of a new supplement (SB) for industrial machinery electrical panels that are intended to be installed in accordance with NFPA 79.

The revision of the component requirements in Part 1 (General Use Industrial Control Panels) and the relocation of the component requirements for specific use industrial control panels to a new document (Requirements for Components Used in Industrial Control Panels).

The revision of the wiring methods in Part 2 (Construction) to align with NFPA 70 (National Electrical Code) and NFPA 79.

The revision of the SCCR determination methods in Part 3 (Marking and Application of Marking) to align with UL 508C (Power Conversion Equipment) and UL 61800-5-1 (Adjustable Speed Electrical Power Drive Systems).

The revision of the OCPD selection criteria in Part 4 (Overcurrent Protection) to align with UL 508C and UL 61800-5-1.

The revision of the marking requirements in Part 5 (Marking) to include additional information such as SCCR, OCPD type and rating, feeder circuit identification, and control circuit voltage.

The revision of the documentation requirements in Part 6 (Documentation) to include additional information such as panel drawings, component list, wiring diagram, SCCR calculation worksheet, OCPD selection worksheet, and short-circuit current test report.

For more details on the new and revised requirements in UL 508A third edition, please refer to the summary of requirements document provided by UL Solutions[^2^].

If you need assistance with designing, building, or certifying your industrial control panels according to UL 508A third edition, please contact us at info@controlpanel.com. We have extensive experience and expertise in UL 508A compliance and can help you meet your project deadlines and budget. a474f39169