Pennsylvania Code
Title 34 - LABOR AND INDUSTRY
Part I - Department of Labor and Industry
Chapter 39 - SAFETY STANDARDS-GENERAL
Subchapter B - ELECTRIC SAFETY
FUSES AND OTHER CUT-OUTS, SWITCHES AND CONTROLLERS
Section 39.151 - Accessible and indicating

Switches, automatic cut-outs, starting rheostats and other control devices shall be readily accessible to authorized persons. They shall be arranged or marked so as to identify the equipment controlled by them, and, except fuses, shall indicate whether they are open or closed. They shall be installed so as to minimize the danger of accidental operation, and where practicable so that gravity cannot close them; such switches that close by gravity shall be provided with a proper latch or stop block to prevent accidental closing. If practicable, the blades of knife switches should be dead when the switches are open.