Pennsylvania Code › Title 34 - LABOR AND INDUSTRY › Part I - Department of Labor and Industry › Chapter 39 - SAFETY STANDARDS-GENERAL › Subchapter B - ELECTRIC SAFETY › PROTECTIVE ARRANGEMENTS › Section 39.199 - Guarding or isolating live parts

Current through Register Vol. 54, No. 28, July 13, 2024
(a)
					 Ungrounded current-carrying parts of electrical utilization equipment, such as
					 bus bars, conductors, and terminals, operating at over 150 volts to ground and
					 not isolated by elevation at least 8 feet above floor line shall, if
					 practicable, be provided with suitable permanent enclosures or other guards
					 arranged so as to prevent persons or conducting objects from inadvertently
					 coming in, or being brought into, contact with the parts in question and at the
					 same time so as to permit ready access to authorized persons for making
					 adjustments or repairs, unless excepted under the provisions of subsection (b).
					 Enclosures may consist of suitable casings or suitable insulating coverings.
					 The continuous insulating covering of conductors should be depended upon only
					 when the circuit is grounded or entirely unexposed to leakage or induction from
					 higher voltage circuits, and when it is impracticable to install more suitable
					 guards. It should be depended upon then only when the covering is not exposed
					 to liability of mechanical injury, and is very substantial, thoroughly dry, and
					 contains no noninsulating flameproofing compound or oil-soaked rubber. It is
					 recommended that in addition to the protection afforded by such coverings the
					 insulating mats or platforms called for in subsection (b) be used. If it is
					 necessary that covers, casings, or barriers at any time be removed from the
					 otherwise exposed current-carrying parts which they guard, while these parts
					 are alive, the covers, casings or barriers should be of insulating material, or
					 so arranged that they are not readily brought in contact with the live parts.
					 Mats may be of wood, held together by wood pins, or of cork matting, linoleum
					 or rubber. The material and construction should be suitable for the voltage
					 concerned and for the prevailing conditions. If subject to moisture or to
					 accumulations of conducting dust, flyings, or chips, mats should present
					 surfaces minimizing the hazards from these sources. Reference should be made to
					 §
											39.214 (relating to guarding
					 conductors).
(b) If
					 current-carrying parts at over 150 volts to ground are necessarily exposed,
					 ungrounded, and within 8 feet from the floor line, surrounding conducting
					 floors and other noncurrent-carrying surfaces within reach shall be covered
					 with suitable insulating platforms, mats or other insulating devices. Reference
					 should also be made to §
											39.198 (relating to working space
					 about electrical equipment). The guarding of current-carrying parts obviates
					 the necessity for such insulating devices, and when the use of the latter is
					 impracticable, from the nature of the location or processes carried on, guards
					 should always be used.
(c) Except
					 on fenced rights of way or other locations to which only qualified persons are
					 admitted, trolley or crane collector wires and third rails, whether indoors or
					 out, shall be so isolated by elevation, or be provided with suitable guards so
					 arranged that persons do not inadvertently touch the current-carrying parts
					 while in contact with the ground, or with conducting material connected to the
					 ground, and shall be provided with warning signs effective whenever the
					 conductors are alive. Damp wood, concrete floors, and metal parts of crane cabs
					 are considered as grounded. Trolley-contact conductors indoors shall be so
					 supported that in case of a single break, contact with the floor is not made.
					 Reference should be made to §
											39.106 (relating to isolating live
					 parts by elevation).
(d) Bare parts
					 at different potentials shall be effectively separated. Such parts in circuits
					 of large capacity or operating at over 300 volts shall, if practicable, unless
					 provided with the enclosure or other guard specified in subsection (a), be
					 provided with suitable barriers, if otherwise they would be liable to be short
					 circuited by tools or other conducting objects.
This section cited in 34 Pa. Code §
													39.191 (relating to
						  applicability); 34 Pa. Code §
													39.192 (relating to scope); 34 Pa.
						  Code §
													39.193 (relating to modification
						  or waiver of provisions); 34 Pa. Code §
													39.197 (relating to grounding); 34
						  Pa. Code §
													39.201 (relating to storage
						  batteries, transformers, and lightning arresters); 34 Pa. Code §
													39.212 (relating to mechanical and
						  thermal protection); 34 Pa. Code §
													39.214 (relating to guarding
						  conductors); 34 Pa. Code §
													39.219 (relating to grounding or
						  isolating service conduits); 34 Pa. Code §
													39.246 (relating to guarding
						  current-carrying parts); and 34 Pa. Code §
													39.291 (relating to guarding live
						  and moving parts).