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 39.238 - Guarding live parts of switches and automatic cut-outs

(a) Manual switches, except those under 150 volts to ground and limited to 60 amperes by cut-outs in series, shall have suitable casings or guards protecting the operator from danger of contact with current-carrying parts, or shall be provided with insulating handles and suitable insulating guard disks or shields so arranged between the handles and the live parts as to prevent the hand from slipping into contact with live parts or being burned by arcing at the switches.

(b) Current-carrying parts of switches or automatic cut-outs operating at over 150 volts to ground shall be provided with enclosing guards, effective during ordinary operation, if accessible to other than properly qualified persons. Those having current-carrying parts exposed may be made inaccessible to other than properly qualified persons by enclosure in locked cabinets or rooms.

(c) If switches or cut-outs above 150 volts to ground are not guarded during operation, suitable insulating floors, mats or platforms shall be provided on which the operator shall stand while operating the switches or adjusting automatic cut-outs, and, unless operators invariably wear suitable insulating gloves while handling the switches, any conducting walls or machine frames within three feet shall be provided with suitable insulating guards. The suitable guarding of live parts will obviate the necessity for such insulating floors and other devices, and if use of such devices is impracticable from the nature of the location or mechanical process carried on, guards should always be used.

(d) Switches shall, if practicable, be so connected as to have no live blades exposed to contact when a switch is open.