Industrial control equipment for the North American market - UL approval.
The standard covers industrial control devices and their accessories for starting, stopping, regulating, controlling and protecting electric motors, rated up to 1500 V, for ordinary locations and ambient temperatures of 0–40 °C; examples include solid-state starters, pushbutton stations, relays, proximity sensors, timing relays, lighting dimming systems and industrial microprocessor systems.
The scope excludes products transferred to separate standards: industrial control panels (UL 508A), fire-pump controllers (UL 218), adjustable-speed drives (UL 61800-5-1), hazardous-location equipment (UL 1203), temperature and refrigeration controls (UL 873, UL 60730 series), magnetic and manual motor controllers (UL 60947-4-1) and programmable controllers (UL 61010-2-201).
UL 508 certification (UL Listed for complete devices, UL Recognized for components) permits a control device to be installed in UL 508A control panels and NEC installations in the United States; combined with CSA C22.2 No. 14, it supports cULus marking for Canada.
UL transitioned some categories to standards harmonized with IEC. New and modified designs of magnetic, manual and combination motor controllers, overload relays and industrial control switches (categories NLDX, NLRV, NKJH, NKCR, NRNT) have been evaluated exclusively to UL 60947-4-1 since January 26, 2017, and UL 508 certifications in these categories were withdrawn as of January 27, 2017; programmable controllers transitioned to UL 61010-2-201 (by April 1, 2016), power conversion equipment to UL 61800-5-1 (by February 1, 2020), and solid-state motor controllers to UL 60947-4-2 (by March 21, 2021).
UL 508 remains applicable to categories not transferred, including relays and pushbutton stations. In the EU, the certificate does not replace a declaration of conformity to EN IEC 60947-x.
Approval is issued as UL Listed or UL Recognized Component with production surveillance; categories transferred to UL 60947-4-1 use the third edition of UL 60947-4-1 (ANSI/UL 60947-4-1A), harmonized with IEC 60947-4-1 with national deviations.
Bi-national UL 60947-4-2 / CSA C22.2 No. 60947-4-2 standards also apply in the United States and Canada, and in January 2025 NEMA submitted a request for a bi-national UL/CSA 60947-4-3 standard intended eventually to replace the relevant UL 508 and CSA C22.2 No. 14 requirements for solid-state AC controllers.
For contactors, starters and overload relays, look for UL 60947-4-1 in the datasheet (UL 508 certifications in these categories expired in 2017); for relays, pushbutton stations and similar accessories, UL 508 remains applicable. Check the UL file number, Listed or Recognized status, cULus marking, and the certified rated voltage and current.
