Pennsylvania Code › Title 34 - LABOR AND INDUSTRY › Part I - Department of Labor and Industry › Chapter 39 - SAFETY STANDARDS-GENERAL › Subchapter B - ELECTRIC SAFETY › METHODS OF PROTECTIVE GROUNDING › Section 39.67 - Attachment of ground conductor

Current through Register Vol. 54, No. 28, July 13, 2024
(a)
Direct current distributing systems.
The neutral of three-wire
					 direct current systems shall be grounded at one or more supply stations, but
					 not at individual services nor within buildings served. One side of a two-wire
					 direct current system may be grounded, but at one station only. In three-wire
					 systems the neutrals entering any junction box should be bonded together, but
					 the box should not be specially grounded. In two-wire systems the grounded side
					 of the circuit should be insulated from ground except at the station ground
					 connection.
(b)
Alternating
					 current distribution systems.
All secondary distribution systems shall
					 be grounded at the building services or near the transformer (or transformers)
					 either by direct ground connection or by the use of a system ground wire to
					 which are connected the grounded conductors of many secondary mains and which
					 is itself effectually grounded at intervals which fulfill, for any secondary
					 utilizing the system ground wire, the resistance and current carrying
					 requirements of §
											39.69 (relating to ground
					 resistance). Single-phase, three-wire distribution systems shall be grounded at
					 the neutral conductor. Two-wire, single-phase systems shall be grounded at the
					 neutral point or on either conductor. Two-wire, single-phase and two or three
					 phase systems shall, in general, be grounded at that point of the system which
					 brings about the lowest voltage from ground of unguarded current carrying parts
					 of connected devices and also permits most convenient grounding. If one phase
					 of a two or three phase system is used for lighting, that phase should be
					 grounded and at the neutral conductor, if one is used. In the absence of direct
					 grounds at all building services, ground connections shall be made to the
					 grounded neutral or other grounded conductor of a secondary system supplying
					 more than one utilization equipment, at intervals that will fulfill the
					 resistance and current-carrying requirements of § 39.69. If the
					 secondaries of transformers are supplying a common set of mains, the fuses
					 shall be installed only at such points as will not cause the loss of the ground
					 connections after the fuses in the transformer circuits or mains have been
					 blown. Multiple grounds are preferable in all cases, because of the assurance
					 provided against loss of the protection afforded by the chance disconnection of
					 any ground connection. Grounds other than the single ground connection at the
					 building service shall not be made to alternating current secondaries within
					 buildings. Reference should be made to §
											39.66 (relating to nature of
					 ground connection).
(c)
Lightning arresters.
The connection to a lightning arrester
					 shall be at such a point that its ground conductor is as short and straight as
					 practicable. Ground conductors for lightning arresters shall not pass through
					 iron or steel conduits unless electrically connected to both ends of such
					 conduits.
(d)
Equipment and
					 wire runways.
The point at which the ground conductor is attached to
					 equipment or wire runways shall, if practicable, be readily
					 accessible.
This section cited in 34 Pa. Code §
													39.61 (relating to applicability);
						  34 Pa. Code §
													39.62 (relating to scope); 34 Pa.
						  Code §
													39.63 (relating to modification or
						  waiver of provisions); 34 Pa. Code §
													39.65 (relating to ground
						  conductor); 34 Pa. Code §
													39.103 (relating to protective
						  grounding); 34 Pa. Code §
													39.183 (relating to ground wires);
						  34 Pa. Code §
													39.197 (relating to grounding); 34
						  Pa. Code §
													39.219 (relating to grounding or
						  isolating service conduits); 34 Pa. Code §
													39.292 (relating to grounding
						  noncurrent-carrying parts); and 34 Pa. Code §
													39.304 (relating to grounding of
						  arresters for signaling systems).