UL 508

Please note: All interim revisions for this edition available at time of your purchase will be included.

1.1 These requirements cover industrial control devices, and devices accessory thereto, for starting, stopping, regulating, controlling, or protecting electric motors. These requirements also cover industrial control devices or systems that store or process information and are provided with an output motor control function(s). This equipment is for use in ordinary locations in accordance with the National Electrical Code, NFPA 70.

1.2 These requirements cover devices rated 1500 volts or less. Industrial control equipment covered by these requirements is intended for use in an ambient temperature of 0 - 40?C (32 - 104?F) unless specifically indicated for use in other conditions.

1.3 These requirements also cover industrial control panels that are assemblies of industrial control devices and other devices associated with the control of motor operated and related industrial equipment. Examples of devices in an industrial control panel are industrial control devices, disconnecting means, motor branch circuit protective devices, temperature control devices, and electrical instruments.

1.4 Examples of industrial control devices described in 1.1 are:

1.Manual, magnetic, and solid-state starters and controllers.
2.Thermal, magnetic, and solid-state overload relays.
3.Pushbutton stations, including selector switches and pilot lights.
4.Control circuit switches and relays.
5.Float, flow, pressure, and vacuum-operated switches.
6.Resistors and rheostats.
7.Proximity switches.
8.Time-delay relays and switches.
9.Resistors and rheostats intended for industrial heating and lighting, including those for motor generator fields.
10.Control devices intended for industrial heating and lighting.
11.Solid-state time-delay relays.
12.Programmable controllers.
13.Numerical control systems.
14.Lighting dimmer systems and controls.
15.Mercury-tube switches.
16.Definite purpose controllers.
17.Solid-state logic controllers.
18.Industrial microprocessor/computer systems.
19.Variable voltage autotransformer.
20.Motor starting autotransformer.

1.5 An industrial control panel for the control of metalworking machine tools or plastics machinery is judged on the basis of compliance with the applicable requirements of this standard as well as requirements in the Standard for Industrial Machinery, NFPA 79.

1.6 A fire pump controller is judged on the basis of compliance with the applicable requirements in this standard and additional requirements in the Standard for Centrifugal Fire Pumps, NFPA 20.

1.7 An adjustable-speed drive and accessories or modules for use with an adjustable-speed drive are covered by the Standard for Power Conversion Equipment, UL 508C.

1.8 Equipment intended for use in hazardous locations as defined by the National Electrical Code, NFPA 70, are covered by the Standard for Industrial Control Equipment for Use in Hazardous (Classified) Locations, UL 698.

1.9 Devices that regulate temperature and/or control refrigeration equipment are covered by the Standard for Temperature-Indicating and Regulating Equipment, UL 873, and other applicable standards.

1.10 Electrical instruments are covered by the Standard for Electrical Analog Instruments- Panel Board Types, UL 1437.

1.11 A product that contains features, characteristics, components, materials, or systems new or different from those covered by the requirements in this standard, and that involves a risk of fire or of electric shock or injury to persons shall be evaluated using appropriate additional component and end-product requirements to maintain the level of safety as originally anticipated by the intent of this standard. A product whose features, characteristics, components, materials, or systems conflict with specific requirements or provisions of this standard does not comply with this standard. Revision of requirements shall be proposed and adopted in conformance with the methods employed for development, revision, and implementation of this standard.

1.11 revised August 22, 2000