Illinois Administrative Code › Title 83 - PUBLIC UTILITIES › Part 305 - CONSTRUCTION OF ELECTRIC POWER AND COMMUNICATION LINES › Table A - Vertical Separation of Crossarms Carrying Conductors

Current through Register Vol. 48, No. 28, July 12, 2024
1. BASIC SEPARATION.
The separations given in the following table are for crossarms
				carrying conductors of 0 to 50,000 volts attached to fixed supports.
2. INCREASED SEPARATION FOR VOLTAGES
			 EXCEEDING 50,000 VOLTS.
For voltages greater than 50,000 volts the clearances in the table
				below shall be increased at the rate of 0.4 inch per 1,000 volts of the
				excess.
Supply conductors: preferably at higher
						  levels 
						  6
Open wires, 0 to 750 volts; cables, having effectively
						  grounded continuous metal sheath, or insulated conductors supported on and cabled
						  together with an effectively grounded messenger, all voltages
15,000 to 50,000
volts
Conductors usually at lower levels
750 to
8,700
8,700 to 15,000
volts
volts
Same
Different
utility
utilities
Communication conductors:
Feet
Feet
Feet
Feet
Feet
General
--------------
1, 2
4
4
6
--------------
6
Use in operation of supply
lines
----------------
2
3
2
4
4
6
Supply conductors:
0 to 750 volts
--------------
2
4
2
4
4
6
750 volts to 8,700 volts
-------------
--------------
4
2
4
4
6
8,700 volts to 15,000 volts:
If worked on alive with long-handled tools and adjacent
						  circuits are neither killed nor covered with shields or protectors
---------------
---------
4
4
6
If not worked on alive except when adjacent circuits (either
						  above or below) are killed or covered by shields or protectors, or by the use of
						  long-handled tools not requiring linemen to go
between live wires
-----------
-----------------
---------
2
5
4
5
4
Exceeding 15,000 volts, but
not exceeding 50,000 volts
-----------------
---------
-----------
-----------
5
4
5
4
1 Where supply circuits of 550 volts or
				less, with transmitted, power of 3,200 watts or less, are run below communication
				circuits in accordance with Rule 220B2 the clearance may be reduced to 2
				feet.
2 In localities where the practice has
				been established or placing on jointly used poles, crossarms carrying supply
				circuits of less than 300 volts to ground and crossarms carrying communication
				circuits at a vertical separation less than specific in the table, such existing
				construction may be continued until the said poles are replaced provided that
				-
The minimum separation between existing crossarms is not
				less than 2 feet, and that -
Extensions to the existing construction shall conform to
				the clearance requirements specified in table 11.
When communication conductors are all in cable, a supply crossarm
				carrying only wires of not more than 300 volts to ground may be placed at not less
				than 2 feet above the point of attachment of the cable to the pole provided that
				-
The nearest supply wire on such crossarm shall be at
				least 30 inches horizontally from the center of the pole, and that -
The cable be placed so as not otherwise to obstruct the
				climbing space.
3 This shall be increased to 4 feet when
				the communication conductors are carried above supply conductors unless the
				communication-line-conductor size is that required for grade C supply lines.
4 Where conductors are operated by
				different utilities, a minimum vertical spacing of 4 feet is recommended.
5 These values do not apply to adjacent
				crossarms carrying phases of the same circuit or circuits.
6 A conductor which is effectively
				grounded throughout its length, and is associated with a supply circuit of 0 to
				22,000 volts may have the clearance specified for cables having effectively grounded
				continuous metal sheath or messenger.