UL 1077:2021 PDF Download

The UL 1077:2021 standard addresses the requirements for supplementary protectors used as overcurrent, overvoltage, or undervoltage protection in electrical appliances or equipment. These protectors are intended for use in situations where branch circuit overcurrent protection is already provided or not required.

The standard emphasizes the importance of ensuring that the supplementary protectors can effectively and continuously function under the actual service conditions of the application. It acknowledges that the acceptability of a protector may be influenced by the specific equipment it is used in, and additional evaluations of features or performance characteristics may be necessary beyond what is specified in the standard.

Furthermore, the standard covers accessory devices that can be installed in or on the protector to serve a secondary function. Examples of such accessories include alarm and auxiliary switches.

It is important to note that devices ensuring a manual restart due to the complete loss of voltage, as well as automatic reset devices that open the circuit based on predetermined time or current/voltage values within an appliance or equipment, are not covered by UL 1077. Instead, they fall under the scope of other standards such as UL 244A (Standard for Solid-State Controls for Appliances) and UL 60730-1 (Standard for Automatic Electrical Controls for Household and Similar Use, Part 1: General Requirements), along with the applicable Part 2 standards from the UL 60730 series. Compliance with these standards fulfills the requirements for such devices.