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
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Case No. |
Nature of Clearance and Class of Voltage of wire, cable or conductor concerned |
Other Wire, cable or conductor concerned |
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A Span wires, guys and messengers |
B Trolley contact conductors 0 - 750 volts |
C Communication conductors |
Supply conductor (including supply cables) |
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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 |
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Vertical Clearance of wires and conductors Crossing in Spans, or Co-Linear with other wires |
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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. |
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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. |
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3 |
Communication conductors |
24 in. (c) |
48 in. |
24 in. |
48 in. (f) |
48 in. |
72 in. |
96 in. |
96 in. |
96 in. |
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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. |
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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. |
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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. |
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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. |
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Vertical separation between conductors and / or cables on different crossarms (excepting related line and buck arms) on the same pole (h) (i) (q) |
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8 |
Communication conductors |
------------ |
------------ |
10 in. |
48 in. |
72 in. |
72 in. |
72 in. |
72 in. |
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9 |
Supply Conductors, service drops and trolley feeders 0-750 volts |
------------ |
------------ |
12 in. (l) |
48 in. |
48 in. |
72 in. |
72 in. |
72 in. |
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10 |
Supply conductors, 750-7500 volts |
------------ |
------------ |
48 in. |
48 in. |
48 in. |
48 in. |
48 in. |
60 in. |
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11 |
Supply conductors 7500-17,000 volts |
------------ |
------------ |
72 in. |
48 in. |
48 in. |
48 in. (o) |
48 in. |
48 in. |
60 in. |
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12 |
Supply conductors 17,000-68,000 volts |
------------ |
------------ |
72 in. |
72 in. |
48 in. |
48 in. |
48 in. |
48 in. |
60 in. |
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13 |
Supply conductors, more than 68,000 volts |
------------ |
------------ |
72 in. |
72 in. |
60 in. |
60 in. |
60 in. |
60 in. |
60 in. |
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Vertical Distance Between conductors on related line arms and buck arms. |
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14 |
Line arms above or below former (p) |
------------- |
------------- |
9 in. |
12 in. (q) |
18 in. |
18 in. |
24 in. |
36 in |
48 in (r) |
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Horizontal separation of conductors on |
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15 |
Pin spacings – same voltage classification on same Crossarm (s) (t) |
------------- |
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3 in. |
11 ½ in. (u) |
11 ½ in. |
17 ½ in. |
24 in. |
36 in |
48 in (r) |
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Incidental pole wiring |
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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
2. Communication 87.4-E
(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
(g) May be reduced under special conditions 54.8-A3
(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