General Order 64 (Table 2)

General Order 64

Section IV

General Clearance Requirements – All Classes Of Lines

TABLE 2

Minimum Allowable Clearance of Wires From Other Wires, Including Vertical Clearance of Wires in Spans; Vertical Separation Between Wires on Co-Linear; Horizontal Separation Between Wires on the Same Crossarm; Vertical Separation Between Wires on Different Linearms on the Same Pole; Vertical Separation Between Wires on Linearms and Wires on Buckarms on the Same Pole; Also Separation Between Wires and Vertical Conductors, Lateral Conductors and Guy Wires.

Nature of Clearance		Voltage and type of line concerned in clearance
		Span Wires, Guys and messengers	Trolley contact wires (a) (c) 0-750 volts	Telephone, telegraph and other signal wires	Trolley feeders (a) service drops, see rule 41 (e), and supply lines 0-750 volts	Supply lines
		Span Wires, Guys and messengers	Trolley contact wires (a) (c) 0-750 volts	Telephone, telegraph and other signal wires		750 - 7,500 volts	7,500 to 17,000 volts	17,000 to 34,000 volts	34,000 to 68,000 volts	Over 68,000 volts
Case No.	Clearance of Wires at Point of Crossing.	A	B	C	D	E	F	G	H	I
Vertical clearance of wires crossing other wires in spans; also vertical separation between wires on one pole line and those on a co-linear pole line (a)
1.	Span wires, guys and messengers	1ft. 6in. (d)	3 ft.	2 ft. (b)	2 ft.	3 ft.	3 ft.	6 ft.	6 ft.	6 ft.
2.	Telephone, telegraph and other signal wires	2 ft. (b)	4 ft. (e)	2 ft. (f)	4 ft. (g)	4 ft.	6 ft.	8 ft.	8 ft.	8 ft.
3.	Supply lines, service drops and trolley feeders, 0-750 volts	2 ft.	4 ft. (h)	4 ft. (g)	2 ft. (f)	4 ft.	4 ft.	8 ft.	8 ft.	8 ft.
4.	Supply lines 750-7,500 volts	3 ft.	4 ft.	4 ft.	4 ft.	4 ft. (i)	6 ft.	8 ft.	8 ft.	8 ft.
5.	Supply lines 7,500-17,000 volts	3 ft.	6 ft.	6 ft.	4 ft.	6 ft.	6 ft.	8 ft.	8 ft.	8 ft.
6.	Supply lines over 17,000 volts	6 ft.	8 ft.	8 ft.	8 ft.	8 ft.	8 ft.	8 ft.	8 ft.	8 ft.
Horizontal Separation of Wires.
7.	Pin Spacing – horizontal separation between wires of same voltage class on same crossarm (j) (k) (l)	---	---	3 in. (m)	11 ½ in. (n) (o)	11 ½ in.	17 ½ in.	24 in.	36 in.	48 in. (p)
Vertical Separation of Wires on Different Linearms on the Same Pole (q)
Crossarm spacing – vertical separation between wires on different linearms on the same pole: (r) (u)
8.	Supply lines, service drops and trolley feeders, 0-750 volts	---	---	4 ft. (s)	1 ft.	4 ft.	4 ft.	6 ft.	6 ft.	6 ft.
9.	Supply lines 750-7,500 volts	---	---	4 ft.	4 ft.	2 ft. (v)	4 ft.	4 ft.	4 ft.	5 ft.
10.	Supply lines 7,500-17,000 volts	---	---	6 ft.	4 ft.	4 ft.	3 ft. (v)	4 ft.	4 ft.	5 ft.
11.	Supply lines 17,000-68,000 volts	---	---	6 ft.	4 ft.	4 ft.	4 ft.	4 ft.	4 ft.	5 ft.
12.	Supply lines over 68,000 volts	---	---	6 ft.	5 ft.	5 ft.	5 ft.	5 ft.	5 ft.	5 ft.
Vertical Separation Between Wires on Linearms and Wires of Buckarms on the Same Pole.
13.	Minimum Buckarm spacing (w) above or below linearms	---	---	---	12 in.	18 in.	18 in.	24 in.	36 in.	48 in. (p)
Separation Between Wires and Vertical Conductors, Lateral Conductors and Guy Wires.
14.	Incidental pole wiring – clearance of wires from span and guy wires of from vertical or lateral conductors of other circuits, on the same or conflicting poles. Use voltage in table corresponding to highest voltage wire concerned in the clearance (t)	---	---	3 in.	3 in.	6 in.	6 in.	12 in.	18 in.	24 in.

References to Rules Modifying Normal Clearances in Table 2.

(a) Trolley contact conductors and feeders of over 750 volts shall be classed as ordinary supply lines to be governed by the clearance required for similar voltage. The clearances specified in the table do not apply between trolley wires and their supporting span wires, nor to trolley wires used as span wires, and span wires supporting trolley feed wires.

(b) This does not prohibit the attachment of private telephone, telegraph and signal wires not exceeding 750 volts to trolley span wires, provided the attached wires are mounted on suitable insulators.

(c) These clearances apply only where pantagraph or similar contact device is used. In all other cases these clearances must be increased to correspond to the elevations given in Table 1, Case (2).

(d) This does not prohibit messengers from being in contact at intersection where they are mechanically connected so as to form continuous messengers for changing directions of cable or for branch lines, or for supporting trolley wires or fixtures on systems of the same voltage.

(e) This may be reduced to 2 feet when cables are properly protected.

(f) This may be reduced, if cable or wires are suitably supported to prevent contact.

(g) A clearance of 2 feet below Class “S” lines may be permitted provided the crossing is not within 6 feet from any pole concerned in the crossing and the voltage to ground of the supply service drop does not exceed 300 volts. Police signal, police telephone and fire alarm circuits which operate at less than 400 volts to ground, or less than 750 volts between any two points of the circuit (provided that if the voltage exceed 150 volts, the power transmitted shall not exceed 150 watts), may be permitted a 2-foot clearance between other Class “S” lines and supply lines not exceeding 750 volts. Where this construction is necessitated, said police signal, police telephone and fire alarm conductors shall be insulated by a covering equivalent in insulating efficiency to double braid weatherproofing; in installing such circuits the outside positions on the crossarms shall be used first to facilitate the climbing and working space as much as possible.

(h) This clearance need not apply between trolley feeders and trolley contact wires of the same potential and system.

(i) Where the lines involved are owned by the same utility a clearance of 3 feet may be used.

(j) Where conductors carrying voltage below 750 volts are installed on the same crossarm with conductors carrying above 750 volts, all conductors of the lower voltage shall be on the same crossarm on the side of the pole opposite the conductors of higher voltage and the minimum distance between conductors of the lower voltage and conductors of the higher voltage shall be 36 inches horizontally. Where two crossarms or more of the above construction are on the same pole the horizontal spacing of conductors shall be as above and the vertical spacing between linearms shall be 36 inches. (See Appendix E, Fig. 38.)

(k) Properly insulated cables, duplex, triples or twisted-pair conductors, whether single or grouped are considered single conductors. No special clearance is required between separate conductors or such cables or multiple conductor groups. The clearances mentioned do not apply to wires of the same phase or polarity between which there is no difference of potential.

(l) The horizontal separation between wires supported by insulators of the disc or suspension type, unless dead ended or otherwise prevented from swinging, shall be 25 per cent greater than the values given in the table.

(m) This does not apply at points of transposition of signal conductors.

(n) Conductors of the same voltage and polarity may have less spacing.

(o) Where insulated conductors of voltage not exceeding 750 volts are supported on vertical racks in spans averaging not more than 150 feet, the minimum of Table 2, calling for horizontal separation between wires may be reduced to one-third of the values given and these values used for the vertical separation. Where such construction is used the top conductors must not be less than 6 feet below supply lines carrying in excess of 750 volts, unless protected by a suitable guard arm securely fastened to the pole directly over the top conductor of the rack under which conditions the vertical spacing from the top conductor to the supply line may be not less than 4 feet. When rack construction is used the rule of Table 1, requiring a distance from the wire to the center of the pole of 15 inches shall not apply providing the rack construction is placed on one side of the pole only.

(p) The pin spacing for voltage exceeding 68 kilovolts shall be 48 inches, plus ½ inch per kilovolt in excess of 68 kilovolts.

(q) The spacings of Items 8 to 12, inclusive, are clearances between conductors on different linearms on the same poles. In no case, due to variation in length of pins and insulator sizes, shall these clearances be reduced more than 25 per cent of the values given.

(r) Where the wires of a circuit are on different crossarms, as in vertical or triangular arrangements, the crossarm spacing here specified between such arms may be reduced to allow conductor spacing equivalent to the table values for the pin spacing of wires of the circuit voltage; provided that where more than one circuit is concerned all circuits on the arms in question shall similarly arranged and of the same voltage class. (See Appendix E, Fig 37.)

(s) When signal lines are in cable on poles jointly used with supply conductors a crossarm supporting only supply conductors not exceeding 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 25 inches horizontally from the center of pole. When the supply conductor is a service drop not exceeding 250 volts and a crossing as mentioned in note (g) above, can not be made without violating other rules, a service clearance crossarm may be placed on the signal crossing pole 2 feet above or below the point of attachment of the signal wires or cables to the pole; provided that the nearest supply wire on such crossarm shall be at least 25 inches horizontally from the center of the pole. When supply conductors not exceeding 300 volts to ground are supported by pole top extensions attached to toll line poles. The minimum clearance over toll line conductors on the end positions of the crossarm shall be not less than 2 feet; when in addition to the pole top extension a crossarm bracket is used for clearance over such above mentioned toll line conductors on the end position of the crossarm, the minimum clearance shall not be less than 12 inches. In all of the above cases the consent of the owner to whose pole attachment is made shall be obtained. See note (g) above for location of police signal, police telephone and fire alarm circuits.

(t) This does not apply to properly insulated wires or cables supported on messengers, as between the wires and their supporting messengers; nor does it apply to conductors at points of dead end attachment (through strain insulators) to guy wires; nor to properly insulated wires or cables run on the surface of poles or structures and protected with a casing equal in insulation and durability to a wooden casing 1 ½ inches thick.

(u) This does not apply to incidental pole wiring such as connections to street lamps, wiring transformers or switches, wires or cables run vertically on poles, nor to “lead” wires or lateral conductors. Pole wiring must conform to the last section of Table 2.

(v) While 2 feet to 3 feet is allowed under this situation to care for congested conditions it is recommended that 4 feet be employed wherever practicable.

(w) In no case shall the vertical separation between wires on linearms and wires on buckarms be greater than one-half the vertical separation between wires on different linearms on the same pole as given in Table 2, items 8 to 12, inclusive. Where conductors carrying a voltage below 750 volts are installed on the same crossarm with conductors carrying above 750 volts the minimum buckram spacing shall not be less than 24 inches above or below the linearms. (See Appendix E, Figs. 37 and 38).