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General Order 64-A

 

Section III

 

General Provisions

 

Table 1

 

Basic Minimum Allowable Vertical Clearance of Wire Above Railroads, Thoroughfares and Ground; Also clearances from Buildings, Structures or Other Obstructions

(Letter References Denote Modifications of Minimum Clearances as Referred to in Note Following this Table)

 

Case No

Nature of Clearance

Wire or Conductor Concerned

A

Span wires (other than trolley span wires), overhead guys and messengers

B

Communication conductors (open wire and cable), supply service drops of 0-750 volts

C

Trolley Contact, feeder and span wires 0-750 volts

D

Supply conductors 0-750 volts and supply cables treated as in Rule 57.8

E

Supply conductors and supply cables, 750-17,000 volts

F

Supply Conductors and supply cables more than 17,000 volts

1

Crossing above tracks of railroads which transport or propose to transport freight cars (max height 15 ft 1in) where not operated by overhead contact wires (a) (b)

25 ft

25 ft

22 ft

25 ft

28 ft

34 ft

2

 Crossing or paralleling above tracks of railroads operated by overhead trolleys (b) (c)

26 ft (d) (e)

26 ft (e) (f)

19 ft (g) (h)

27 ft (e)

30 ft (e)

34 ft

3

 Crossing or along thoroughfares in Urban districts or crossings thoroughfares in rural districts (b)

18 ft (i) (j)

18 ft (k)

19 ft

20 ft

25 ft

30 ft

4

 Above ground along thoroughfares in rural districts or across other areas capable of being transversed by vehicles or agricultural equipment.

7 ft (j)

15 ft (l)

19 ft

16 ft

25 ft

30 ft (m)

5

Above ground along private fenced rights of way and areas accessible to pedestrians only. 

7 ft (j)

10 ft (n)

19 ft

12 ft

17 ft

25 ft

6

 Vertical clearance above buildings and bridges (or other structures which do not ordinarily support conductors and on which men can walk) whether attached or unattached.

8 ft (p)

8 ft (p)

8 ft

8 ft

12 ft

12 ft

7

 Distance of conductor from center line of pole, whether attached or unattached (q) (r) (s) (u)

--------------

15 in. (t) (v)

15 in. (w)

15 in. (x)

15 or 18 in. (x) (y)

18 in (x)

8

 Horizontal clearance of conductor from buildings (except generating and substations), bridges or other structures upon which conductor is not ordinarily supported (and upon which men may work) where such conductor is not attached thereto. (o) (r) (z)

--------------

3 ft (ee)

3 ft.

3 ft.

6 ft. (aa)

6 ft.

9

Distance of conductor from surface of pole, crossarm, wall or other supporting structure upon which it may be supported, provided it complies with Case 7 above (q) (s) (x) (bb) 

--------------

(cc)

3 in (dd)

3 in

3 in

pin spacing shown in Table 2 Case 15

 

References to Rules Modifying Normal Clearances in Table 1.

 

 

(a)    May be reduced and shall be increase depending on car height.

1.    Supply Lines  54.4-B1b

2.    Communication Lines  84.4-B1b

 

(b)    Special clearances are provided for traffic signal equipment  58.2

 

(c)    May be reduced and shall be increased, depending on trolley throw.

1.    Supply Lines  54.4-B1a

2.    Communication Line  84.4-B1a

 

(d)    May be reduced for street light span wires  58.3-A2

 

(e)    May be reduced where suitably protected

1.    Supply cables, messengers and guys  54.4-B2

2.    Communication cables, messengers and guys  84.4-B2

 

(f)    May be reduced, depending on the height of trolley contact conductors.

1.    Supply service drops  54.8-A5

2.    Communication service drops  84.8-A5

 

(g)    May be reduced in subways, tunnels or under bridges  74.4-E

 

(h)    Shall be increased where freight cars are transported  74.4-B1

 

(i)    Applies only at crossings

 

(j)    Applies at lowest point of overhead guy wire.

 

(k)     May be reduced at curb lines and over private driveways, under porches, etc.

1.    Supply service drops 54.8-A2

2    .Communication service drops  84.8-A2

 

(l)    May be reduced for communication conductors  84.4-A3

 

(m)    Special clearances for voltages more than and less than 25,000   54.4-A2

  

(n)    May be reduced under special conditions

1.    Communication conductors  84.4-A2

2.    Railway signal cables   84.4-A4

 

(o)    Reduced clearances permitted under special conditions

1.    Supply conductors  54.4-E

2.    Communication conductors  84.4-E

87.4-F

 

(p)    May be reduced crossing roofs of buildings, etc.

1.    Overhead guys.

Supply  56.4-A

Trolley  76.4-A

Communication  86.4-A

2.    Supply service drops  54.8-A6

3.    Communication conductors and cables  84.4-E

84.8-A7

 

(q)    May be reduced for cables and messengers attached directly to poles.

1.    Supply   57.4-F

2.    Trolley   77.7

3.    Communication  87.4-B2

 

(r)    Shall be increased for suspension insulators, under certain conditions  35

 

(s)    May be reduced for suitably protected vertical and lateral runs.

1.    Lateral supply conductors of open wire construction  54.4-D1

74.4-D

2.    Vertical runs of supply conductors  54.6-A

3.    Vertical runs of communication conductors  84.6-A

4.    Vertical supply risers  54.6-B

5.    Vertical communication risers  84.6-B

6.    Rack construction   54.9-B3

54.9-B4

7.    Bond wires  53.4

8.    Supply cables  57.4-F

92.1-A

9.    Communication cables  87.4-B2

87.4-D2

 

(t)    Special provisions for police and fire alarm circuits require increased clearances  92.1-F

 

(u)    Shall be increased where conductors are dead-ended directly to pole, provided no energized portion enters the climbing or working space  

54.4-C6

54.7-A5

77.6-A3

 

(v)    May be reduced for communication conductors, under special provisions.

1.    Open wire conductors attached directly to poles  84.4-C2

2.    Conductors and cables supported by cross arms  84.4-D1b

87.4-D1

 

(w)    May be reduced where Class T conductors are of same potential and polarity  74.4-D

 

(x)    May be reduced for pole top and dead end construction  54.4-C7

 

(y)    Clearance requirements due to voltage variations  54.4-D4

54.4-D3

 

(z)    May be reduced for conductors and cables adjacent to buildings, etc.

1.    Supply (conductors)  54.4-E

(cables)        57.4-G

2.    Communication  84.4-E

 

(aa)    May be reduced for circuits of 750-7500 volts  54.4-E

 

(bb)    May be reduced for tap wires to cut-outs, switches, etc.  58.5-A

 

(cc)    Minimum clearance of communication wires and cables  84.4-D2

 

(dd)    Reduced clearances to Class T conductors attached to under side of structures

1.    Trolley feeder wires  74.4-E

2.    Trolley contact wires  122

 

(ee)    May be reduced for:

1.    Supply service drops 0-750 volts  54.8-A6

2.    Communication cables  84.4-E

3.    Communication service drops 84.8-A7