General Order 64 (Table 1)

General Order 64

Section IV

General Clearance Requirements – All Classes Of Lines

Table 1

Minimum Allowable Clearance of Wires Above Railroads, Streets, Highways or the Ground; Also Clearance From Buildings, Poles, Structures and Other Obstructions.

Nature of Clearance		Span Wires (other than trolley span wires), guy wires	Signal circuits, supply service drops 0-750 volts	Trolley contact wires, trolley span wires, trolley feeder wires	Supply lines, 0 - 750 volts	Supply lines, 750 - 17,000 volts	Supply lines over 17,000 volts
Case. No		A	B	C	D	E	F
1.	Vertical clearance or wires crossing above tracks of railroads which transport or propose to transport standard freight cars where not operated by overhead trolley contact wires (a)	25 ft.	25 ft.	22 ft.	25 ft.	28 ft.	34 ft.
2.	Vertical clearance of wires crossing above tracks of railroads which are operated by overhead trolley contact wires, also of trolley wires along and above tracks of same (b)	27 ft. (c)	27 ft. (d)	22 ft. 19 ft. (e)	27 ft.	30 ft.	34 ft.
3.	Vertical clearance above the ground or wires crossing or along streets, roads, highways or alleys in urban districts or of wires crossing same in rural districts	18 ft. (f)	18 ft.	19 ft.	20 ft.	25 ft.	30 ft.
4.	Vertical clearance above the ground of wires along streets, roads, highways or alleys in urban districts or of wires crossing same in rural districts	----	16 ft. (g) (h)	19 ft.	16 ft. (h)	25 ft.	30 ft. (i)
5.	Vertical clearance above the ground or wires along private right of way fenced or accessible to pedestrians only	----	10 ft.	19 ft.	12 ft.	17 ft.	25 ft.
6.	Distance of wire from center of pole, whether attached or unattached (j) (k)	----	15 in.	15 in.	15 in.	15 in. and 18 in. (l)	18 in.
7.	Vertical clearance above buildings and bridges of wires crossing above, attached or unattached to same (p)	----	8 ft.	8 ft.	8 ft.	12 ft.	12 ft.
8.	Horizontal clearance from walls of buildings (except generating and substations) of wires paralleling but not attached to such walls (n) (p)	----	3 ft.	3 ft.	3 ft.	6 ft.	6 ft.
9.	Distance of wire from surface of pole (o), crossarm, line structure, walls of buildings and sides of bridges structures to which wires are attached (m) (p)	----	----	3 in. (q)	3 in.	3 in	One-fourth value of pin spacing given in Table 2 (t)
10.	Clearance of wires adjacent to but not attached to bridge structures (r)	----	3 ft.	(s)	3 ft.	5 ft.	8 ft

References to Rules Modifying Normal Clearances in Table 1.

(a) The clearance herein specified above tracks are based on the use of freight cars not exceeding 15 feet in height from top of rail to top of running board. For railroads not using, and not proposing to use or interchange cars with railroads using standard equipment, these clearances may be reduced accordingly, provided that in no case shall any of the clearances be reduced more than 2 feet.

(b) The clearance herein specified above tracks are based on maximum throw of trolley pole of 26 feet above rails. For railroads operated by overhead trolley contact wire where the throw of trolley pole is greater or less than 26 feet, these clearances shall be increased or reduced accordingly, provided that in no case shall the clearance be less than 25 feet.

(c) A clearance of 26 feet will be permitted for span wires supporting street lights suspended over railroads operated by overhead trolley contact wires, provided however, that the clearance from the bottom of the lamp be not less than 24 feet. On streets where there are no railroads the clearance from the bottom lamp may be reduced to 20 feet. Where street lamps are supported by pole fixtures or brackets and said fixtures or brackets extended more than 48 inches horizontally, (or if they extend less than 48 inches and the voltage exceed 750 volts) the clearance from the bottom of the lamp shall not be less than 20 feet. This clearance may be reduced to 15 feet if the fixture or bracket extends less than 48 inches horizontally and the voltage is less than 750 volts. (See Appendix E, Figs. 8 and 9.)

(d) This may be reduced to 25 feet as follows:

1. Where wires or cables are properly protected.

2. Where service wires are above streets upon which are operated pantograph trolleys only (as distinguished from pole trolleys).

3. Where Service wires are properly protected.

(e) For roads not transporting standard freight cars this clearance of 19 feet may apply.

(f) Only guy or span wires crossing streets need comply.

(g) Rural telephone lines may have a clearance of 15 feet above ground, along streets, roads, highways or alleys in rural districts.

(h) Supply service drops or supply lines 0 to 750 volts, crossing over spaces open to vehicular traffic shall have a minimum clearance of 18 feet above the ground.

(i) Supply lines over 17,000 volts crossing arid or mountainous districts, may have a clearance of 25 feet from the ground upon special permission from the Railroad Commission.

(j) This shall not apply to Class “S” wires or cables, which are attached to a pole to which are attached no wire or cable other than Class “S” wires or cables, nor shall it apply to supply or signal wires or cables in cases where same are placed vertically on poles, nor to bridle or jumper wires on any pole which are attached to Class “S” wires on same pole; nor to any aerial cable, as between such cable and any pole which it originates or terminates; nor shall not be held to apply to “lead wires” to arc and incandescent lamps or transformers placed on poles; nor to any wire or cable where same is attached to the top of the pole as between it and the said pole; nor to aerial cable containing Class “S” wire where the same is attached to a pole on which no other wires or cables, than wires continuing from said cable are maintained; provided that supply wires or cables are in no case maintained on the same side of the street or highway on which said aerial cable is placed; nor shall this apply to Class “T” wires of the same polarity where no other Class “T” wires attached to the same pole. Where supply service drops not exceeding 300 volts to ground are supported by pole top extensions attached to toll line poles, this clearance shall not apply either to the toll line construction or to the supply service drops. (See Table 2, note (s).)

(k) This does not apply to rack construction (See note (o), Table 2.)

(l) From 750 to 7500 volts the minimum clearance shall be 15 inches and from 7500 to 17,000 volts the minimum clearance shall be 18 inches. (See Appendix E, Fig. 6.)

(m) Does not apply to clearance from surface of poles, crossarms, etc., for connection to fuses, cutouts and similar devices used with transformers or branch lines; also does not apply when wires or cables are run vertically on poles similar structures, provided the installation is made in accordance with Rule 63 (d). (See Appendix E, Fig. 20.)

(n) These clearances shall be increased as much as possible to facilitate fire fighting.

(o) Wires run adjacent to a pole, either across the lead or in co-linear construction, must be maintained at all times so that the distance of any wire to the center of pole specified in this table is maintained. This practically necessitates the use of a clearance crossarm. This need not be done, however, if it is possible to maintain the distance specified herein.

(p) f supply wires in excess of 300 volts to ground are run on the surface of buildings (except generating stations and substations, or bridge structures, the installation, if of open wire or cable constructions, shall be made in accordance with the orders of the Industrial Accident Commission covering Electric Utilization equipment. Wires in excess of 5000 volts should not be run over buildings, if it is possible to avoid it.

(q) This applies to Class “T” wires from 0 to 750 volts. If of higher voltage they shall be classed as ordinary supply lines, and will take the clearances provided for such lines. Where trolley contact wires are attached to bridge structures trolley troughs shall, where practicable, be installed. (See note (s).)

(r) Bridges include only structures as are used for foot, vehicular or train traffic, and not those structures often used along railroads for suspension of the trolley wires, trolley feeders or signal equipment. These latter structures are classed as poles or towers, and will make clearance accordingly.

(s) No special clearance is required between trolley contact wires run under the bridge and the bridge, but properly insulated trolley troughs shall, where practicable, be installed to prevent contact between the trolley pole and steel structures, in case the trolley slips from the contact wire, except where the clearance is sufficient to eliminate the possibility of such accident.

(t) Where suspension insulators are used this spacing shall be figured on the assumption that the maximum deflection is 45 degrees from the vertical. (See Rule 42, Par. 2, and Appendix E, Fig. 6.)