Change List for this Rule

 

Original Version

Table 2

Basic Minimum Allowable Clearance of Wires from Other Wires at Crossings, in Midspans 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 conductors0-750 volts

C

Communication conductors (including open wire, cables and service drops) Supply conductor (including supply cables)

D
0-750 volts (including service drops and trolley feeders (a) )

Supply conductor (including supply cables)

E
750 - 7,500 volts

F

7,500 - 20,000 volts

G 20,000 - 35,000 volts

H

35,000 - 75,000 volts

I

Over 75,000 - 150,000 volts

J

150,000 - 300,000 volts

K (kk)

300,000 - 550,000 volts


Clearance between wires, cables, and conductors not supported on the same poles, vertically at crossings in spans, and radially where collinear or approaching crossing










 

 

1

Span wires, guys and messengers (b)

18 (c)

48 (d, e)

24 (e)

24 (e)

36 (f)

36

72

72

78

78(gg)

138(hh)

2

Trolley contact conductors 0-750 volts

48 (d, e)

-

48 (d)

48 (d, h)

48

72

96

96

96

96 (gg)

156(hh)

3

Communication conductors

24 (e)

48 (d)

24

48 (i)

48 (dd)

72

96

96

96

96 (gg)

156(hh)

4

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

24 (e)

48 (d, h)

48 (i)

24

48

48

96

96 (oo)

96

96 (gg)

156(hh)

5

Supply conductors, 750-7500 volts

36 (f)

48

48 (dd)

48

48 (h)

72

96

96 (oo)

96

96 (gg)

156(hh)

6

Supply conductors 7500-20,000 volts

36

72

72

48

72

72

96

96 (oo)

96

96 (gg)

156(hh)

7

Supply conductors, more than 20,000 volts

72 (g)

96 (g)

96 (g)

96 (g)

96 (g) (oo)

96 (g) (oo)

96 (g) (oo)

96 (g) (oo)

96 (g)

96 (gg)

156(hh)


Vertical separation between conductors and / or cables on separate crossarms or other supports at different levels (excepting on related line and buck arms on the same pole and in adjoining Midspans)










 

 

8

Communication conductors and service drops

-

-

12 (j)

48 (k, l, m, n, pp)

48 (k)

72 (m, n)

72(m)

72

78

87 (gg)

147(hh)

9

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

-

-

48 (k, l, m, n, pp)

24 (h, k, m, o)

48 (k, m, p)

48 (k, m, q)

72(m) (nn)

72

78

87 (gg)

147(hh)

10

Supply conductors, 750-7500 volts

-

-

48 (k)

48 (k, m, p)

48 (m, o, r, ee)

48 (m, q)

48(q)

48(q)

60(ff)

90 (gg)

150(hh)

11

Supply conductors 7500-20,000 volts

-

-

72 (m, n)

48 (k, m, q)

48 (m, q)

48 (m, o, q, r, ee)

48(q)

48(q)

60(ff)

90 (gg)

150(hh)

12

Supply conductors 20,000- 75,000 volts

-

-

72 (m)

72 (m, nn)

48 (m, q)

48 (m, q)

48(o, q)

48(o, q)

60(ff)

90 (gg)

150(hh)

13

Supply conductors, more than 75,000 volts

-

-

72

72

60 (q)

60(q)

60(q)

60(q)

60(ff)

90 (gg)

150(hh)


Vertical arms above or below conductors on related line arms and buck arms.










 

 

14

Line arms above or below related buck arms (s, t)

-

-

6

12 (u)

18 (u)

18 (u)

24

36

60(ff)

90 (gg)

150(hh)


Horizontal separation of conductors on same crossarm










 

 

15

Pin spacings of longitudinal conductors, vertical conductors and service drops

-

-

3(x)

11 ˝ (h, x)

11 ˝ (x)

17 ˝ (x)

24 (x)

36

60(ff)

90 (gg)

150(hh)


Radial separation of conductors on same crossarm, pole or structure Incidental pole wiring










 

 

16

Conductors, tap or lead wires of different circuits (v, y, z)

-

-

3 (x)

11 ˝ (h, x)

11 ˝ (x)

17 ˝ (x)

24 (x)

36

60(ff)

90 (gg)

150(hh)

17

Conductors, tap or lead wires of same circuits (v, y, z)

-

-

3

3

6

6

12

18

60(ff)

90 (gg)

150(hh)


Radial separation between guys and conductors










 

 

18

Guys passing conductors supported on other poles (excluding poles of same circuit), and guys approximately parallel to conductors supported on the same poles

-

-

3 (bb)

12

18

18

30

36

36 (ff)

78 (gg)

138(hh)

19

Guys and spans wires passing conductors supported on the same poles 

(cc)

 

3

3

6

9

12

18

24

48 (ll)

86 (jj)

 

Vertical and Horizontal insulator-Vertical clearance between conductors

 

 

 

 

 

 

 

 

 

 

 

20

Vertical Clearance between conductors of the same circuit on Horizontal insulators

-

-

-

-

24

24

24

36 or 48 (ii) (mm)

48 (mm)

48(mm)

48(mm)

  (a)    The clearances in Column D are also applicable to supply cables of any voltage under certain conditions    57.4

(b)    Clearances for guys and span wires apply vertically at crossings; see Case 18 for radial clearances from conductors.

1.  Supply guys and span wires from conductors 56.4-C
2.  Supply guys and span wires from guys and span wires 56.4-D1
3.  Communication guys and span wires from conductors 86.4-C
4.  Communication guys and span wires from guys and span wires    86.4-D1

(c)    Not applicable between messengers or span wires of the same system.

1.  Supply messengers 57.4-E
2.  Trolley span wires 77.4-D
3.  Communication messengers    87.4-G

(d)    Protection required on guys, span wires, messengers, and cables where within trolley throw

1.  Supply Guys and Span wires 56.4-B2
2.  Supply Messengers and Cables 57.4-B2
3.  Communication guys and span wires 86.4-B2
4.  Communication messengers  87.4-B2

(e)    Not applicable to certain conductors supported on trolley span wires.

1.  Trolley contact and feeder conductors 74.4-G
2.  Trolley feeder conductors 78.1
3.  Trolley system communication conductors 78.2
4.  Foreign conductors   78.3

(f)    Increased clearance required over trolley contact conductors of 750-7500 volts    74.4-G2

(g)    Shall be increased for conductors of more than 75,000 volts.  As required by Table 2 Columns I, J, and K.

 

(h)    May be reduced for certain conductors of Class T circuits of the same system    74.4-C

(i)    May be reduced for service drops under special conditions.

1.  Supply service drops and communication line conductors 54.8-C1a
2.  Supply service drops and communication service drops 54.8-C4
3.  Communication service drops and supply line conductors 84.8-D1a
4.  Communication service drops and supply service drops   84.8-D4

(j)    May be reduced or shall be increased for certain communication conductors or cables.

        1.  Open wire conductors, attached to poles, within 3 feet of topmost conductor 84.4-C1c
        2.  Line conductors of police or fire-alarm circuits and service drops from other communication circuits.   84.8-D1b
        3.  Cables and messengers attached to poles  87.4-C3

(k)    Special clearances for 0-750 volt conductors in rack configuration and messengers and cables attached to poles.

1.  Supply conductors of 0-750 volts in rack configuration 54.9
2.  Supply cables and messengers attached to poles 57.4-F
3.  Communication cables and messengers attached to poles 87.4-C3
4.  On Jointly used poles  92.1

(l)    May be reduced for service drops, and police or fire-alarm conductors, under special conditions.

1.  Supply service drops and communication line conductors 54.8-C1b
2.  Supply service drops on clearance arms 54.8-C2
3.  Supply service drops on pole-top extensions 54.8-C3
4.  Supply service drops and communication service drops 54.8-C4
5.  Communication service drops and police, fire-alarm or supply line conductors 84.8-D1b
6.  Communication service drops on clearance arms 84.8-D2
7.  Communication service drops on pole-top extensions 84.8-D3
8.  Communication service drops and supply service drops 84.8-D4
9.  Police or fire-alarm conductors 92.2

(m)    May be reduced for lead wires

1.  Supply lead wires above supply conductors 54.4-C6
2.  Supply drip loops above communication conductors   92.1-F3


(n)    May be reduced for supply conductors and private communication conductors of the same ownership    89.2-B

(o)    May be reduced or increased for triangular or vertical configuration or for pole-top construction.

1.  Triangular or vertical configuration on crossarms 54.4-C1c
2.  Dead-ended on pole in vertical configuration 54.4-C4


(p)    May be reduced for supply service drops of 0-750 volts    54.8-C6

(q)    Shall be increased between circuits where conductors of more than 7500 volts are at pole top.    54.4-D8

(r)    May be reduced under special conditions

1.  Supply conductors of 750-7500 volts 54.4-C1a
2.  Supply conductors of 7500-20,000 volts    54.4-C1b


(s)    Does not apply where conductors do not cross.

1.  Supply conductors of different phase polarity 54.4-C2a
2.  Communication conductors   84.4-C1a


(t)    Shall not be applied consecutively both above and below the same supply conductors    54.4-2a

(u)    Shall be increased where conductors of different classifications are supported on the same crossarms.

1.  Supply conductors of 0-750 volts and conductors of 7500-20,000 volts 32.4-A2
2.  Supply conductors of 0-750 volts and conductors of 750-7500 volts   32.4-A3

(v)    Not applicable to certain kinds of conductors.

1.  Supply conductors of same phase or polarity 54.4-C3c
2.  Insulated supply conductors in multiple-conductor cables 57.4-C
3.  Communication insulated conductors or multiple-conductor cables   87.4-C1


(w)    Shall apply radially to conductors on brackets attached to crossarms.

1.  Supply conductors 54.4-C3b
2.  Communication conductors    84.4-C1b

(x)    Shall be increased between conductors of different classifications supported on the same crossarm.

1.  Supply conductors of different voltage classification 32.4-A
2.  Supply circuits of 0-750 volts and communication circuits 32.4-B
3.  Supply circuits and private communication circuits.   89.2-A


(y)    Special clearances for unprotected supply conductors from one level to another level   

54.6-A
58.2-B3
92.1-F5


(z)    Not applicable to the following:

1.  Clearances between conductors at different levels specified in Cases 8 to 13 inclusive.
2.  Supply lateral conductors, suitably protected 54.6-C
3.  Supply vertical runs, suitably protected   54.6-D
4.  Supply risers, suitably protected 54.6-E
5.  Communication Conductors 87.4-C1


(aa)    Not applicable between cables and their supporting messengers.

1.  Supply  57.4-D
2.  Communication  87.4-F

(bb)    May be reduced for communication guys and communication conductors supported on the same poles   

1. Supply 56.4-C
2. Communication 86.4-C3


(cc)    Clearance required between guys.

1.  Supply guys, crossing 56.4-D2
2.  Supply guys, approximately parallel 56.4-D3
3.  Communication guys, crossing 86.4-D2
4.  Communication guys, approximately parallel  86.4-D3

(dd)    Shall be increased where within 6 feet of a pole    103.5

(ee)    May be decreased in partial underground distribution    54.4-C4c

(ff) shall be increased by 0.40 inches per kV in excess of 75 kV


(gg)  shall be increased by 0.40 inches per kV in excess of 150 kV


(hh)   shall be increased by 0.40 inches per kV in excess of 300 kV


(ii)   shall be increased by 0.25 inches per kV in excess of 150 kV


(jj)   shall be increased by 0.25 inches per kV in excess of 300 kV


(kk)   proposed clearances to submitted to the CPUC prior to construction for circuits in excess of 550 kV  


(ll)         36-inch clearance applies 35 kV to 68kV

          48-inch clearance applies over 68 kV


(mm)  vertical clearance shall be increased by ˝ inch for each kilovolt over 68 kV


(nn)  The vertical separation between supply conductors and service drops Of 0-750 volts and 20,000-22,500-volt conductors may be reduced to 48 inches.


(oo)  May be reduced to 72 inches for conductors of 20,000-22,500 volts. 


(pp)  May be reduced to 36 inches vertically at midspan only when the supply conductors consist of abrasion resistant cable with a grounded metallic sheath or neutral–supported cable as specified in Rules 57 and 54.10 .

 

Strikeout and Underline Version

Table 2

Basic Minimum Allowable Clearance of Wires from Other Wires at Crossings, in Midspans 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 conductors0-750 volts

C

Communication conductors (including open wire, cables and service drops) Supply conductor (including supply cables)

D
0-750 volts (including service drops and trolley feeders (a) )

Supply conductor (including supply cables)

E
750 - 7,500 volts

F

7,500 - 20,000 volts

G 20,000 - 35,000 volts

H

35,000 - 75,000 volts

I

Over 75,000 - 150,000 volts

J

150,000 - 300,000 volts

K (kk)

300,000 - 550,000 volts


Clearance between wires, cables, and conductors not supported on the same poles, vertically at crossings in spans, and radially where collinear or approaching crossing










 

 

1

Span wires, guys and messengers (b)

18 (c)

48 (d, e)

24 (e)

24 (e)

36 (f)

36

72

72

78

78(gg)

138(hh)

2

Trolley contact conductors 0-750 volts

48 (d, e)

-

48 (d)

48 (d, h)

48

72

96

96

96

96 (gg)

156(hh)

3

Communication conductors

24 (e)

48 (d)

24

48 (i)

48 (dd)

72

96

96

96

96 (gg)

156(hh)

4

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

24 (e)

48 (d, h)

48 (i)

24

48

48

96

96 (oo)

96

96 (gg)

156(hh)

5

Supply conductors, 750-7500 volts

36 (f)

48

48 (dd)

48

48 (h)

72

96

96 (oo)

96

96 (gg)

156(hh)

6

Supply conductors 7500-20,000 volts

36

72

72

48

72

72

96

96 (oo)

96

96 (gg)

156(hh)

7

Supply conductors, more than 20,000 volts

72 (g)

96 (g)

96 (g)

96 (g)

96 (g) (oo)

96 (g) (oo)

96 (g) (oo)

96 (g) (oo)

96 (g)

96 (gg)

156(hh)


Vertical separation between conductors and / or cables on separate crossarms or other supports at different levels (excepting on related line and buck arms on the same pole and in adjoining Midspans)










 

 

8

Communication conductors and service drops

-

-

12 (j)

48 (k, l, m, n, pp)

48 (k)

72 (m, n)

72(m)

72

78

87 (gg)

147(hh)

9

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

-

-

48 (k, l, m, n, pp)

24 (h, k, m, o)

48 (k, m, p)

48 (k, m, q)

72(m) (nn)

72

78

87 (gg)

147(hh)

10

Supply conductors, 750-7500 volts

-

-

48 (k)

48 (k, m, p)

48 (m, o, r, ee)

48 (m, q)

48(q)

48(q)

60(ff)

90 (gg)

150(hh)

11

Supply conductors 7500-20,000 volts

-

-

72 (m, n)

48 (k, m, q)

48 (m, q)

48 (m, o, q, r, ee)

48(q)

48(q)

60(ff)

90 (gg)

150(hh)

12

Supply conductors 20,000- 75,000 volts

-

-

72 (m)

72 (m, nn)

48 (m, q)

48 (m, q)

48(o, q)

48(o, q)

60(ff)

90 (gg)

150(hh)

13

Supply conductors, more than 75,000 volts

-

-

72

72

60 (q)

60(q)

60(q)

60(q)

60(ff)

90 (gg)

150(hh)


Vertical arms above or below conductors on related line arms and buck arms.










 

 

14

Line arms above or below related buck arms (s, t)

-

-

6

12 (u)

18 (u)

18 (u)

24

36

60(ff)

90 (gg)

150(hh)


Horizontal separation of conductors on same crossarm










 

 

15

Pin spacings of longitudinal conductors, vertical conductors and service drops

-

-

3(x)

11 ˝ (h, x)

11 ˝ (x)

17 ˝ (x)

24 (x)

36

60(ff)

90 (gg)

150(hh)


Radial separation of conductors on same crossarm, pole or structure Incidental pole wiring










 

 

16

Conductors, tap or lead wires of different circuits (v, y, z)

-

-

3 (x)

11 ˝ (h, x)

11 ˝ (x)

17 ˝ (x)

24 (x)

36

60(ff)

90 (gg)

150(hh)

17

Conductors, tap or lead wires of same circuits (v, y, z)

-

-

3

3

6

6

12

18

60(ff)

90 (gg)

150(hh)


Radial separation between guys and conductors










 

 

18

Guys passing conductors supported on other poles (excluding poles of same circuit), and guys approximately parallel to conductors supported on the same poles

-

-

3 (bb)

12

18

18

30

36

36 (ff)

78 (gg)

138(hh)

19

Guys and spans wires passing conductors supported on the same poles 

(cc)

 

3

3 (bb)

6

9

12

18

24

48 (ll)

86 (jj)

 

Vertical and Horizontal insulator-Vertical clearance between conductors

 

 

 

 

 

 

 

 

 

 

 

20

Vertical Clearance between conductors of the same circuit on Horizontal insulators

-

-

-

-

24

24

24

36 or 48 (ii) (mm)

48 (mm)

48(mm)

48(mm)

  

 

(a)    The clearances in Column D are also applicable to supply cables of any voltage under certain conditions    57.4

(b)    Clearances for guys and span wires apply vertically at crossings; see Case 18 for radial clearances from conductors.

1.  Supply guys and span wires from conductors 56.4-C
2.  Supply guys and span wires from guys and span wires 56.4-D1
3.  Communication guys and span wires from conductors 86.4-C
4.  Communication guys and span wires from guys and span wires    86.4-D1

(c)    Not applicable between messengers or span wires of the same system.

1.  Supply messengers 57.4-E
2.  Trolley span wires 77.4-D
3.  Communication messengers    87.4-G

(d)    Protection required on guys, span wires, messengers, and cables where within trolley throw

1.  Supply Guys and Span wires 56.4-B2
2.  Supply Messengers and Cables 57.4-B2
3.  Communication guys and span wires 86.4-B2
4.  Communication messengers  87.4-B2

(e)    Not applicable to certain conductors supported on trolley span wires.

1.  Trolley contact and feeder conductors 74.4-G
2.  Trolley feeder conductors 78.1
3.  Trolley system communication conductors 78.2
4.  Foreign conductors   78.3

(f)    Increased clearance required over trolley contact conductors of 750-7500 volts    74.4-G2

(g)    Shall be increased for conductors of more than 75,000 volts.  As required by Table 2 Columns I, J, and K.

 

(h)    May be reduced for certain conductors of Class T circuits of the same system    74.4-C

(i)    May be reduced for service drops under special conditions.

1.  Supply service drops and communication line conductors 54.8-C1a
2.  Supply service drops and communication service drops 54.8-C4
3.  Communication service drops and supply line conductors 84.8-D1a
4.  Communication service drops and supply service drops   84.8-D4

(j)    May be reduced or shall be increased for certain communication conductors or cables.

        1.  Open wire conductors, attached to poles, within 3 feet of topmost conductor 84.4-C1c
        2.  Line conductors of police or fire-alarm circuits and service drops from other communication circuits.   84.8-D1b
        3.  Cables and messengers attached to poles  87.4-C3

(k)    Special clearances for 0-750 volt conductors in rack configuration and messengers and cables attached to poles.

1.  Supply conductors of 0-750 volts in rack configuration 54.9
2.  Supply cables and messengers attached to poles 57.4-F
3.  Communication cables and messengers attached to poles 87.4-C3
4.  On Jointly used poles  92.1

(l)    May be reduced for service drops, and police or fire-alarm conductors, under special conditions.

1.  Supply service drops and communication line conductors 54.8-C1b
2.  Supply service drops on clearance arms 54.8-C2
3.  Supply service drops on pole-top extensions 54.8-C3
4.  Supply service drops and communication service drops 54.8-C4
5.  Communication service drops and police, fire-alarm or supply line conductors 84.8-D1b
6.  Communication service drops on clearance arms 84.8-D2
7.  Communication service drops on pole-top extensions 84.8-D3
8.  Communication service drops and supply service drops 84.8-D4
9.  Police or fire-alarm conductors 92.2

(m)    May be reduced for lead wires

1.  Supply lead wires above supply conductors 54.4-C6
2.  Supply drip loops above communication conductors   92.1-F3


(n)    May be reduced for supply conductors and private communication conductors of the same ownership    89.2-B

(o)    May be reduced or increased for triangular or vertical configuration or for pole-top construction.

1.  Triangular or vertical configuration on crossarms 54.4-C1c
2.  Dead-ended on pole in vertical configuration 54.4-C4


(p)    May be reduced for supply service drops of 0-750 volts    54.8-C6

(q)    Shall be increased between circuits where conductors of more than 7500 volts are at pole top.    54.4-D8

(r)    May be reduced under special conditions

1.  Supply conductors of 750-7500 volts 54.4-C1a
2.  Supply conductors of 7500-20,000 volts    54.4-C1b


(s)    Does not apply where conductors do not cross.

1.  Supply conductors of different phase polarity 54.4-C2a
2.  Communication conductors   84.4-C1a


(t)    Shall not be applied consecutively both above and below the same supply conductors    54.4-2a

(u)    Shall be increased where conductors of different classifications are supported on the same crossarms.

1.  Supply conductors of 0-750 volts and conductors of 7500-20,000 volts 32.4-A2
2.  Supply conductors of 0-750 volts and conductors of 750-7500 volts   32.4-A3

(v)    Not applicable to certain kinds of conductors.

1.  Supply conductors of same phase or polarity 54.4-C3c
2.  Insulated supply conductors in multiple-conductor cables 57.4-C
3.  Communication insulated conductors or multiple-conductor cables   87.4-C1


(w)    Shall apply radially to conductors on brackets attached to crossarms.

1.  Supply conductors 54.4-C3b
2.  Communication conductors    84.4-C1b

(x)    Shall be increased between conductors of different classifications supported on the same crossarm.

1.  Supply conductors of different voltage classification 32.4-A
2.  Supply circuits of 0-750 volts and communication circuits 32.4-B
3.  Supply circuits and private communication circuits.   89.2-A


(y)    Special clearances for unprotected supply conductors from one level to another level   

54.6-A
58.2-B3
92.1-F5


(z)    Not applicable to the following:

1.  Clearances between conductors at different levels specified in Cases 8 to 13 inclusive.
2.  Supply lateral conductors, suitably protected 54.6-C
3.  Supply vertical runs, suitably protected   54.6-D
4.  Supply risers, suitably protected 54.6-E
5.  Communication Conductors 87.4-C1


(aa)    Not applicable between cables and their supporting messengers.

1.  Supply  57.4-D
2.  Communication  87.4-F

(bb)    May be reduced for communication guys and communication conductors supported on the same poles   

1. Supply 56.4-C4
2. Communication 86.4-C3


(cc)    Clearance required between guys.

1.  Supply guys, crossing 56.4-D2
2.  Supply guys, approximately parallel 56.4-D3
3.  Communication guys, crossing 86.4-D2
4.  Communication guys, approximately parallel  86.4-D3

(dd)    Shall be increased where within 6 feet of a pole    103.5

(ee)    May be decreased in partial underground distribution    54.4-C4c

(ff) shall be increased by 0.40 inches per kV in excess of 75 kV


(gg)  shall be increased by 0.40 inches per kV in excess of 150 kV


(hh)   shall be increased by 0.40 inches per kV in excess of 300 kV


(ii)   shall be increased by 0.25 inches per kV in excess of 150 kV


(jj)   shall be increased by 0.25 inches per kV in excess of 300 kV


(kk)   proposed clearances to submitted to the CPUC prior to construction for circuits in excess of 550 kV  


(ll)         36-inch clearance applies 35 kV to 68kV

          48-inch clearance applies over 68 kV


(mm)  vertical clearance shall be increased by ˝ inch for each kilovolt over 68 kV


(nn)  The vertical separation between supply conductors and service drops Of 0-750 volts and 20,000-22,500-volt conductors may be reduced to 48 inches.


(oo)  May be reduced to 72 inches for conductors of 20,000-22,500 volts. 


(pp)  May be reduced to 36 inches vertically at midspan only when the supply conductors consist of abrasion resistant cable with a grounded metallic sheath or neutral–supported cable as specified in Rules 57 and 54.10 .

 

Final Version

Table 2

 

Basic Minimum Allowable Clearance of Wires from Other Wires at Crossings, in Midspans 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 conductors0-750 volts

C

Communication conductors (including open wire, cables and service drops) Supply conductor (including supply cables)

D
0-750 volts (including service drops and trolley feeders (a) )

Supply conductor (including supply cables)

E
750 - 7,500 volts

F

7,500 - 20,000 volts

G 20,000 - 35,000 volts

H

35,000 - 75,000 volts

I

Over 75,000 - 150,000 volts

J

150,000 - 300,000 volts

K (kk)

300,000 - 550,000 volts


Clearance between wires, cables, and conductors not supported on the same poles, vertically at crossings in spans, and radially where collinear or approaching crossing










 

 

1

Span wires, guys and messengers (b)

18 (c)

48 (d, e)

24 (e)

24 (e)

36 (f)

36

72

72

78

78(gg)

138(hh)

2

Trolley contact conductors 0-750 volts

48 (d, e)

-

48 (d)

48 (d, h)

48

72

96

96

96

96 (gg)

156(hh)

3

Communication conductors

24 (e)

48 (d)

24

48 (i)

48 (dd)

72

96

96

96

96 (gg)

156(hh)

4

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

24 (e)

48 (d, h)

48 (i)

24

48

48

96

96 (oo)

96

96 (gg)

156(hh)

5

Supply conductors, 750-7500 volts

36 (f)

48

48 (dd)

48

48 (h)

72

96

96 (oo)

96

96 (gg)

156(hh)

6

Supply conductors 7500-20,000 volts

36

72

72

48

72

72

96

96 (oo)

96

96 (gg)

156(hh)

7

Supply conductors, more than 20,000 volts

72 (g)

96 (g)

96 (g)

96 (g)

96 (g) (oo)

96 (g) (oo)

96 (g) (oo)

96 (g) (oo)

96 (g)

96 (gg)

156(hh)


Vertical separation between conductors and / or cables on separate crossarms or other supports at different levels (excepting on related line and buck arms on the same pole and in adjoining Midspans)










 

 

8

Communication conductors and service drops

-

-

12 (j)

48 (k, l, m, n, pp)

48 (k)

72 (m, n)

72(m)

72

78

87 (gg)

147(hh)

9

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

-

-

48 (k, l, m, n, pp)

24 (h, k, m, o)

48 (k, m, p)

48 (k, m, q)

72(m) (nn)

72

78

87 (gg)

147(hh)

10

Supply conductors, 750-7500 volts

-

-

48 (k)

48 (k, m, p)

48 (m, o, r, ee)

48 (m, q)

48(q)

48(q)

60(ff)

90 (gg)

150(hh)

11

Supply conductors 7500-20,000 volts

-

-

72 (m, n)

48 (k, m, q)

48 (m, q)

48 (m, o, q, r, ee)

48(q)

48(q)

60(ff)

90 (gg)

150(hh)

12

Supply conductors 20,000- 75,000 volts

-

-

72 (m)

72 (m, nn)

48 (m, q)

48 (m, q)

48(o, q)

48(o, q)

60(ff)

90 (gg)

150(hh)

13

Supply conductors, more than 75,000 volts

-

-

72

72

60 (q)

60(q)

60(q)

60(q)

60(ff)

90 (gg)

150(hh)


Vertical arms above or below conductors on related line arms and buck arms.










 

 

14

Line arms above or below related buck arms (s, t)

-

-

6

12 (u)

18 (u)

18 (u)

24

36

60(ff)

90 (gg)

150(hh)


Horizontal separation of conductors on same crossarm










 

 

15

Pin spacings of longitudinal conductors, vertical conductors and service drops

-

-

3(x)

11 ˝ (h, x)

11 ˝ (x)

17 ˝ (x)

24 (x)

36

60(ff)

90 (gg)

150(hh)


Radial separation of conductors on same crossarm, pole or structure Incidental pole wiring










 

 

16

Conductors, tap or lead wires of different circuits (v, y, z)

-

-

3 (x)

11 ˝ (h, x)

11 ˝ (x)

17 ˝ (x)

24 (x)

36

60(ff)

90 (gg)

150(hh)

17

Conductors, tap or lead wires of same circuits (v, y, z)

-

-

3

3

6

6

12

18

60(ff)

90 (gg)

150(hh)


Radial separation between guys and conductors










 

 

18

Guys passing conductors supported on other poles (excluding poles of same circuit), and guys approximately parallel to conductors supported on the same poles

-

-

3

12

18

18

30

36

36 (ff)

78 (gg)

138(hh)

19

Guys and spans wires passing conductors supported on the same poles 

(cc)

 

3

3 (bb)

6

9

12

18

24

48 (ll)

86 (jj)

 

Vertical and Horizontal insulator-Vertical clearance between conductors

 

 

 

 

 

 

 

 

 

 

 

20

Vertical Clearance between conductors of the same circuit on Horizontal insulators

-

-

-

-

24

24

24

36 or 48 (ii) (mm)

48 (mm)

48(mm)

48(mm)

(a)    The clearances in Column D are also applicable to supply cables of any voltage under certain conditions    57.4

(b)    Clearances for guys and span wires apply vertically at crossings; see Case 18 for radial clearances from conductors.

 

(c)    Not applicable between messengers or span wires of the same system.

 

(d)    Protection required on guys, span wires, messengers, and cables where within trolley throw

 

(e)    Not applicable to certain conductors supported on trolley span wires.

 

(f)    Increased clearance required over trolley contact conductors of 750-7500 volts    74.4-G2

(g)    Shall be increased for conductors of more than 75,000 volts.  As required by Table 2 Columns I, J, and K.

 

(h)    May be reduced for certain conductors of Class T circuits of the same system    74.4-C

(i)    May be reduced for service drops under special conditions.

 

(j)    May be reduced or shall be increased for certain communication conductors or cables.

 

(k)    Special clearances for 0-750 volt conductors in rack configuration and messengers and cables attached to poles.

 

(l)    May be reduced for service drops, and police or fire-alarm conductors, under special conditions.

 

(m)    May be reduced for lead wires


(n)    May be reduced for supply conductors and private communication conductors of the same ownership    89.2-B

(o)    May be reduced or increased for triangular or vertical configuration or for pole-top construction.


(p)    May be reduced for supply service drops of 0-750 volts    54.8-C6

(q)    Shall be increased between circuits where conductors of more than 7500 volts are at pole top.    54.4-D8

(r)    May be reduced under special conditions


(s)    Does not apply where conductors do not cross.


(t)    Shall not be applied consecutively both above and below the same supply conductors    54.4-C2a

(u)    Shall be increased where conductors of different classifications are supported on the same crossarms.

 

(v)    Not applicable to certain kinds of conductors.


(w)    Shall apply radially to conductors on brackets attached to crossarms.

 

(x)    Shall be increased between conductors of different classifications supported on the same crossarm.


(y)    Special clearances for unprotected supply conductors from one level to another level   


(z)    Not applicable to the following:


(aa)    Not applicable between cables and their supporting messengers.

 

(bb)    May be reduced for communication guys and communication conductors supported on the same poles   

1. Supply 54.6-C4
2. Communication86.4-C3

(cc)    Clearance required between guys.

 

(dd)    Shall be increased where within 6 feet of a pole    103.5

 

(ee)    May be decreased in partial underground distribution    54.4-C4c

 

(ff) shall be increased by 0.40 inches per kV in excess of 75 kV


(gg)  shall be increased by 0.40 inches per kV in excess of 150 kV


(hh)   shall be increased by 0.40 inches per kV in excess of 300 kV


(ii)   shall be increased by 0.25 inches per kV in excess of 150 kV


(jj)   shall be increased by 0.25 inches per kV in excess of 300 kV


(kk)   proposed clearances to submitted to the CPUC prior to construction for circuits in excess of 550 kV  


(ll)    36-inch clearance applies 35 kV to 68kV

        48-inch clearance applies over 68 kV

 

(mm)  vertical clearance shall be increased by ˝ inch for each kilovolt over 68 kV

 

(nn)    The vertical separation between supply conductors and service drops Of 0-750 volts and 20,000-22,500-volt conductors may be reduced to 48 inches.

 

(oo)    May be reduced to 72 inches for conductors of 20,000-22,500 volts.

 

(pp)    May be reduced to 36 inches vertically at midspan only when the supply conductors consist of abrasion resistant cable with a grounded metallic sheath or neutral–supported cable as specified in Rules 57 and 54.10.