UL 60947-4-2:2014 PDF Download

The UL 60947-4-2:2014 standard sets the requirements for controllers and starters used with circuits of rated voltage up to 1,000 V AC. These controllers and starters may include a mechanical switching device and may or may not have bypass means.

It is important to note that these controllers and starters are not designed to interrupt short-circuit currents, so suitable short-circuit protection should be part of the installation, although not necessarily part of the controller or starter itself. The standard covers controllers and starters associated with separate short-circuit protective devices.

The standard does not apply to the continuous operation of AC motors at speeds other than the normal speed, semiconductor equipment controlling non-motor loads, and electronic AC power controllers covered by IEC 60146. Contactors, overload relays, and control circuit devices used in controllers and starters should comply with their relevant product standard. Mechanical switching devices should meet the requirements of their own IEC product standard, as well as the additional requirements of this standard.

The objectives of the standard are to define the characteristics of controllers and starters and their associated equipment, specify the conditions they need to comply with in terms of operation, dielectric properties, enclosure protection, and construction, outline the tests to be conducted to confirm compliance, and provide information to be given with the equipment or in the manufacturer's literature.

Additionally, there are some modifications specified in Annex dvb, regarding the use of circuit breakers, disconnect switches, fuses, and molded case switches as short-circuit protective devices in combination starters and protected starters. These modifications reference specific requirements listed in Annex dvb, Table dvb.3, Ref. No. 1, 2, and 3.