scope:

Description of Driving Event:

While mounting a tray inside an instrument rack, the bottom lip of the tray made contact with the prongs of an electrical plug located below the tray. This contact caused electrical sparks which cut a hole in the tray, burned the paint off the tray, and ruined the plug.

In order to preclude this electrical hazard from recurring, it is recommended that all U-Ground devices be installed with the ground in the top position. If mounted horizontally, the neutral prong should be in the top position.