UL 20:2021 PDF Download

UL 20:2021 is a standard that outlines the requirements for general-use snap switches. These switches are manually operated and designed to be connected to copper or copper-clad conductors in accordance with the National Electrical Code (NEC) or the Canadian Electrical Code (CE Code). The standard specifies that these switches are intended to be permanently connected and installed in a flush device box or on an outlet-box cover.

The standard applies to both AC and DC rated switches, with load ratings that do not exceed 60 A at 250 V or less, 30 A at 251 V - 600 V, and 2 hp at 125 V - 600 V or less. Additionally, the standard covers AC-only rated switches with load ratings that do not exceed 30 A at 347 VAC or less.

Various types of switches are included in this standard, such as pendant and through-cord switches for field installation on flexible cords, switches for surface mounting with a separable base and cover, self-contained switches for flush mounting without a separate outlet box, AC/DC fixture switches for installation in fixtures controlling incandescent lighting or fans, and single-pole, momentary-contact door switches.

However, there are several types of switches that are not covered by this standard, including clock-operated switches, dimmer switches, industrial control equipment, solid-state single-phase motor speed controls, special-use and AC-only fixture switches, and switches for use in hazardous locations. Separate standards exist for these specific types of switches.

For switches intended for connection to branch-circuit wiring containing aluminum conductors, reference must be made to the Standard for Receptacles and Switches Intended for Use with Aluminum Wire (UL 1567) or Annex B of this standard.