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General Order 64-A

 

Section III

 

General Provisions

 

Table 2

 

Basic Minimum Allowable Clearance of Wires from Other Wires at Crossings and at Supports

(Letter references Denote Modifications of Minimum Clearances Referred to in Notes Following this Table)

All Clearances Are in Inches

 

Case No.

Nature of Clearance and Class of Voltage of wire, cable or conductor concerned

Other Wire, cable or conductor concerned

A

Span wires, guys and messengers

B

Trolley contact conductors 0 - 750 volts

C

Communication conductors

Supply conductor (including supply cables)

D

Supply conductors, service drops and trolley feeders 0 - 750 volts

E

750 - 7,500 Volts

F

7,500 - 17,000 volts

G

17,000 - 34,000 volts

H

34,000 - 68,000 volts

I

Over 68,000 volts

Vertical Clearance of wires and conductors Crossing in Spans, or Co-Linear with other wires

 

 

 

 

 

 

 

 

 

1

Span wires, guys and messengers (a)

18 in. (d)

48 in.

24 in. (c)

24 in.

36 in. (d)

36 in.

72 in.

72 in.

72 in.

2

Trolley contact conductors 0 - 750 volts

48 in. (a)

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

48 in.

48 in. (e)

48 in.

72 in.

96 in.

96 in.

96 in.

3

Communication conductors

24 in. (c)

48 in.

24 in.

48 in. (f)

48 in.

72 in.

96 in.

96 in.

96 in.

4

Supply conductors, service drops and trolley feeders, 0 - 750 volts

24 in.

48 in. (e)

48 in. (g)

24 in.

48 in.

48 in.

96 in.

96 in.

96 in.

5

Supply conductors, 750 - 7500 volts

36 in. (d)

48 in.

48 in.

48 in.

48 in. (e)

72 in.

96 in.

96 in.

96 in.

6

Supply conductors 7500 - 17,000 volts

36 in.

72 in.

72 in.

48 in.

72 in.

72 in.

96 in.

96 in.

96 in.

7

Supply conductors, more than 17,000 volts

72 in.

96 in.

96 in.

96 in.

96 in.

96 in.

96 in.

96 in.

96 in.

Vertical separation between conductors and / or cables on different crossarms (excepting related line and buck arms) on the same pole (h) (i) (q)

 

 

 

 

 

 

 

 

 

8

Communication conductors

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

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

10 in.

48 in. (j) (k)

48 in.

72 in.

72 in.

72 in.

72 in.

9

Supply Conductors, service drops and trolley feeders 0-750 volts

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

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

48 in. (j) (k)

12 in. (l)

48 in.

48 in.

72 in.

72 in.

72 in.

10

Supply conductors, 750-7500 volts

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

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

48 in.

48 in.

48 in. (l) (n)

48 in.

48 in.

48 in.

60 in.

11

Supply conductors 7500-17,000 volts

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

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

72 in.

48 in.

48 in.

48 in. (o)

48 in.

48 in.

60 in.

12

Supply conductors 17,000-68,000 volts

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

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

72 in.

72 in.

48 in.

48 in.

48 in.

48 in.

60 in.

13

Supply conductors, more than 68,000 volts

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

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

72 in.

72 in.

60 in.

60 in.

60 in.

60 in.

60 in.

Vertical  Distance Between conductors on related line arms and buck arms.

 

 

 

 

 

 

 

 

 

14

Line arms above or below former (p)

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

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

9 in.

12 in. (q)

18 in.

18 in.

24 in.

36 in

48 in (r)

Horizontal separation of conductors on

 

 

 

 

 

 

 

 

 

15

Pin spacings same voltage classification on same Crossarm (s) (t)

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

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

3 in.

11 in. (u)

11 in.

17 in.

24 in.

36 in

48 in (r)

Incidental pole wiring

 

 

 

 

 

 

 

 

 

16

Clearance between conductors and span, guy, vertical or lateral wires supported on same pole (Use column corresponding to highest voltage concerned in clearance) (v) (w) (x)

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

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

3 in.

3 in.

6 in.

6 in.

12 in

18 in.

24 in

 

References to Rules Modifying Normal Clearances in Table 2.

 

(a)    Suitable protection required for messengers.

1.    Supply    57.4-E

57.7

2.    Communication    87.4-E

87.7

 

(b)    Reduced clearances for messengers of one system and voltage

1.    Supply    57.4-D

2.    Trolley    77.4-B

3.    Communication      87.4-C

 

(c)     Communication wires of trolley system may be supported by trolley span wires    78.2-A

 

(d)    Trolley contact conductors of 750-7500 volts require increased clearances     74.4-G

 

(e)    Not applicable to trolley feeder and trolley contact wires of same potential and system    74.4-C

 

(f)    May be reduced under special conditions    84.8-A3

84.8-A4

  

(g)    May be reduced under special conditions    54.8-A3

54.8-A4

 

(h)    Reduced clearances for vertical and triangular configuration    54.4-C6

 

(i)   Increased clearances for difference of size or design of pins and insulators    36

 

(j)    May be reduced by use of clearance crossarms.

1.    Supply     54.8-A3b

2.    Communication     84.8-A3b

 

(k)    Reduced clearances for police and fire alarm circuits     92.1-F

 

(l)   Increased clearances required at top of pole    54.4-C7a

 

(m)    Increased clearances required at top of pole    54.4-C7b

(n)    May be reduced for circuits owned and operated by one party    54.4-C4

 

(o)    May be reduced for circuits owned and operated by one party  54.4-C5

 

(p)    Where combination buck arm construction is involved special

clearances shall be used     54.8-B2

 

(q)    Various clearances for rack construction    54.9-B2

 

(r)    Shall be increased for voltages more than 68,000    54.4-C9

 

(s)    Not applicable to certain kinds of conductors.

1.    Not applicable to certain kinds of conductors.    36

2.    Supply    57.4-C

3.    Communication    87.4-B1

 

(t)    Special clearances required for combination arm construction.

1.    General provisions    32.5

2.    Supply     54.8-B

 

(u)    May be reduced

1.    Supply    54.8-A7

2.    Trolley    74.4-C

 

(v)    Reduced clearances between cables and supporting messengers.

1.    Supply    57.4-D

2.    Trolley    77.4-B

3.    Communication    87.4-C

 

(w)    Special clearances for open wire drops.

1.    Supply     54.9-A

2.    Joint pole construction    92.4

 

(x)    Not applicable to lateral conductors suitably protected    54.4-D