Current through Register Vol. 54, No. 45, November 9, 2024
Section 39.160 - Guarding live parts of switches and automatic cut-outs not installed on switchboards(a)Above 750 volts. Switches interrupting circuits over 750 volts shall be operated by means of remote control mechanisms or be provided with suitable casings protecting the operator from danger of contact with current-carrying parts, except as provided in subsection (d), for switches requiring only infrequent attention and located in enclosures from which even the operator is normally excluded. The control devices for switches shall indicate whether switches are open or closed. Lever operated, circuit breaker type switches should be equipped with indicating devices to show, other than by the position of the handles, whether they are open or closed. Automatic cut-outs not suitably isolated by elevation shall be of an incased type or be provided with suitable enclosures for current-carrying parts. Large capacity, high voltage oil switches should, where practicable, be placed away from the operator and operated by remote (or lever) controls, since the blowing up of the oil containers may cause serious injuries to persons in the vicinity. For the purpose of this section voltage in excess of 750 will be included as below 750 where the excess is for the purposes of regulation only.(b)Below 750 volts. Switches interrupting circuits under 750 volts shall be operated by means of remote control mechanisms or be incased during ordinary operation or be provided with insulating handles and insulating guard disks or shields arranged so as to make it unlikely that the hand may come in contact with live parts. Switches below 300 volts to ground may be exempted from the requirements of this subsection.(c)Platforms or mats. Where live parts of switches or automatic cut-outs operating at over 300 volts to ground are not remotely controlled, or provided with enclosing guards effective during ordinary operation or adjustment, or isolated by elevation, suitable insulating floors, mats, or platforms shall be provided on which the operator shall stand while operating the switches or adjusting the automatic cut-outs. Reference should also be made to § 39.105(b) (relating to guarding live parts).(d)Working spaces about occasionally exposed live parts. When switches, disconnectors, and fuses above 750 volts are ordinarily guarded by covers or enclosed in separate rooms, but are occasionally operated without such protection, either by removal of the covers or by entrance into the rooms, adequate working space shall be provided about the live parts, unless effectively isolated by elevation as required by § 39.106 (relating to isolating live parts by elevation), so that the operator is not required to bring any part of his body within the following horizontal distances: | Voltage of parts | Distances (in feet) |
| 750-7,500 | 1 |
| 7,500-30,000 | 2 |
| 30,000-50,000 | 3 |
| 50,000-70,000 | 4 |
| 70,000-100,000 | 5 |
| Above 100,000 | 6 |
(e) The distances given in subsection (d) are slightly greater than those required to be maintained by operators near parts of the corresponding voltage. Reference should also be made to §§ 39.364 and 39.365 (relating to voltages between 750 and 7,500; voltages above 7,500). This is for the purpose of provid,ing against inadvertent movements of operators and to insure that operators of unusual height or size may be protected by this provision.(f) Below 7,500 volts the distance specified in this section may be reduced if the operator uses suitable operating devices. This section cited in 34 Pa. Code § 39.143 (relating to isolation by elevation); 34 Pa. Code § 39.171 (relating to accessibility and convenient attendance); 34 Pa. Code § 39.177 (relating to guarding live parts); and 34 Pa. Code § 39.182 (relating to provisions for disconnecting).