UL 917:2016 PDF Download

The UL 917:2016 standard covers requirements for clock-operated switches with a maximum rating of 600 V. These switches are designed to close and open circuits to a load at predetermined intervals and are intended for use in ordinary locations in accordance with the National Electrical Code.

This standard applies specifically to clock-operated switches that use a variety of mechanisms to actuate the switching contacts, such as clockwork, gear-trains, hand-operated mechanisms, electrically-wound spring motors, electric clock-type motors, or equivalent arrangements. In addition to their switching functions, these devices may also indicate the time of day or a specific time interval.

It is important to note that this standard does not cover clock-operated switches that incorporate electronic timing circuits or switching circuits without separable contacts. Furthermore, clock-operated switches that are incomplete or have restricted performance capabilities are acceptable for use as factory-installed components, as long as any restrictions imposed on the component are eliminated when it is installed.

Additionally, specific provisions are included in the standard for clock-operated switches that are TV rated. Any product that deviates from the requirements or provisions in this standard and presents a risk of fire, electric shock, or injury to persons must be evaluated using appropriate additional component and end-product requirements to maintain an acceptable level of safety.

If a product's features, characteristics, components, materials, or systems conflict with the specific requirements or provisions of this standard, it cannot be deemed compliant. Any necessary revisions to the requirements will be proposed and adopted through the standard's established methods of development, revision, and implementation.