By order of the publisher, historical UL documents are not returnable for any reason. Once you place an order for an historical document, we cannot issue a refund, credit, or exchange of any kind.


These requirements cover open knife switches for use in accordance with the National Electrical Code, ANSI/NFPA-70.

These requirements cover switches with or without fuseholders; switches having individual bases intended for either front or rear wiring connection; and switch parts without bases intended for mounting on switchboards and panelboards. Switches may be single- or multi-pole and with or without quick-break or auxiliary contacts, except where such contacts are specifically required.

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, electric shock, or injury to persons shall be evaluated using the appropriate additional component and end-product requirements to determine that the level of safety as originally anticipated by the intent of this Standard is maintained. A product whose features, characteristics, components, materials, or systems conflict with specific requirements or provisions of this Standard shall not be judged to comply with this Standard. Where appropriate, revision of requirements shall be proposed and adopted in conformance with the methods employed for development, revision, and implementation of this Standard.