Underwriters Laboratories has released a “Standard for Determination of Sharpness of Edges of Electrical Equipment,” U.L. 1439. The UL 1439 standard calls for the use of the Sharp Edge Tester in order to provide an objective and uniform test method for determining compliance with an existing safety requirement.
Most U.L. standards covering consumer products contain a subjective requirement such as “an edge, projection, or corner of an enclosure, opening, frame, guard, knob, handle, or the like, shall be smooth, well rounded, and not sufficiently sharp to constitute a hazard.”


