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Wire Size Charts
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Voltage Drop - Conductors used for panelboard or switchboard main feeders, bilge blowers, electronic equipment, navigation lights, and other circuits where voltage drop must be kept to a minimum, shall be sized for a voltage drop not to exceed three percent. Conductors used for lighting, other than navigation lights, and other circuits where voltage drop is not critical, shall be sized for a voltage drop not to exceed 10 percent.
Conductor Size - To determine conductor size use TABLE IX or TABLE X. Check the conductor size for compliance with the maximum allowable voltage drop. In the event of a conflict between the ampacity table and the voltage drop tables, the larger conductor size shall be used.
To use TABLE IX and TABLE X, measure the length of the conductor from the positive power source connection to the electrical device and back to the negative power source connection in feet. Use the conductor length, the system voltage, and the ampacity, in conjunction with the appropriate volt drop table, i.e., 3 percent or 10 percent – TABLE IX or TABLE X, to determine conductor size.
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Table IX From ABYC E11 - CONDUCTORS SIZED FOR 3 PERCENT DROP IN VOLTAGE
Note: In the event of a conflict between the voltage drop table and the ampacity table, use the larger wire size.
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| Length of Conductor from Source of Current to Device and Back to Source - Feet |
|
10 |
15 |
20 |
25 |
30 |
40 |
50 |
60 |
70 |
80 |
90 |
100 |
110 |
120 |
130 |
140 |
150 |
160 |
170 |
TOTAL
CURRENT
ON CIRUIT
IN AMPS |
12 Volts - 3% Drop Wire Sizes (gauge) - Based on Minimum CM Area |
| 5 |
18 |
16 |
14 |
12 |
12 |
10 |
10 |
10 |
8 |
8 |
8 |
6 |
6 |
6 |
6 |
6 |
6 |
6 |
6 |
| 10 |
14 |
12 |
10 |
10 |
10 |
8 |
6 |
6 |
6 |
6 |
4 |
4 |
4 |
4 |
2 |
2 |
2 |
2 |
2 |
| 15 |
12 |
10 |
10 |
8 |
8 |
6 |
6 |
6 |
4 |
4 |
2 |
2 |
2 |
2 |
2 |
1 |
1 |
1 |
1 |
| 20 |
10 |
10 |
8 |
6 |
6 |
6 |
4 |
4 |
2 |
2 |
2 |
2 |
1 |
1 |
1 |
0 |
0 |
0 |
2/0 |
| 25 |
10 |
8 |
6 |
6 |
6 |
4 |
4 |
2 |
2 |
2 |
1 |
1 |
0 |
0 |
0 |
2/0 |
2/0 |
2/0 |
3/0 |
| 30 |
10 |
8 |
6 |
6 |
4 |
4 |
2 |
2 |
1 |
1 |
0 |
0 |
0 |
2/0 |
2/0 |
3/0 |
3/0 |
3/0 |
3/0 |
| 40 |
8 |
6 |
6 |
4 |
4 |
2 |
2 |
1 |
0 |
0 |
2/0 |
2/0 |
3/0 |
3/0 |
4/0 |
4/0 |
4/0 |
4/0 |
4/0 |
| 50 |
6 |
6 |
4 |
4 |
2 |
2 |
1 |
0 |
2/0 |
2/0 |
3/0 |
3/0 |
4/0 |
4/0 |
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| 60 |
6 |
4 |
4 |
2 |
2 |
1 |
0 |
2/0 |
3/0 |
3/0 |
4/0 |
4/0 |
4/0 |
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| 70 |
6 |
4 |
2 |
2 |
1 |
0 |
2/0 |
3/0 |
3/0 |
4/0 |
4/0 |
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| 80 |
6 |
4 |
2 |
2 |
1 |
0 |
3/0 |
3/0 |
4/0 |
4/0 |
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| 90 |
4 |
2 |
2 |
1 |
0 |
2/0 |
3/0 |
4/0 |
4/0 |
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| 100 |
4 |
2 |
2 |
1 |
0 |
2/0 |
3/0 |
4/0 |
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| . |
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| Length of Conductor from Source of Current to Device and Back to Source - Feet |
|
10 |
15 |
20 |
25 |
30 |
40 |
50 |
60 |
70 |
80 |
90 |
100 |
110 |
120 |
130 |
140 |
150 |
160 |
170 |
TOTAL
CURRENT
ON CIRUIT
IN AMPS |
24 Volts - 3% Drop Wire Sizes (gauge) - Based on Minimum CM Area |
| 5 |
18 |
18 |
18 |
16 |
16 |
14 |
12 |
12 |
12 |
10 |
10 |
10 |
10 |
8 |
8 |
8 |
8 |
8 |
8 |
| 10 |
18 |
16 |
14 |
12 |
12 |
10 |
10 |
10 |
8 |
8 |
8 |
6 |
6 |
6 |
6 |
6 |
6 |
6 |
6 |
| 15 |
16 |
14 |
12 |
12 |
10 |
10 |
8 |
8 |
6 |
6 |
6 |
6 |
6 |
4 |
4 |
4 |
4 |
4 |
2 |
| 20 |
14 |
12 |
10 |
10 |
10 |
8 |
6 |
6 |
6 |
6 |
4 |
4 |
4 |
4 |
2 |
2 |
2 |
2 |
2 |
| 25 |
12 |
12 |
10 |
10 |
8 |
6 |
6 |
6 |
4 |
4 |
4 |
4 |
2 |
2 |
2 |
2 |
2 |
2 |
1 |
| 30 |
12 |
10 |
10 |
8 |
8 |
6 |
6 |
4 |
4 |
4 |
2 |
2 |
2 |
2 |
2 |
1 |
1 |
1 |
1 |
| 40 |
10 |
10 |
8 |
6 |
6 |
6 |
4 |
4 |
2 |
2 |
2 |
2 |
1 |
1 |
1 |
0 |
0 |
0 |
2/0 |
| 50 |
10 |
8 |
6 |
6 |
6 |
4 |
4 |
2 |
2 |
2 |
1 |
1 |
0 |
0 |
0 |
2/0 |
2/0 |
2/0 |
3/0 |
| 60 |
10 |
8 |
6 |
6 |
4 |
4 |
2 |
2 |
1 |
1 |
0 |
0 |
0 |
2/0 |
2/0 |
3/0 |
3/0 |
3/0 |
3/0 |
| 70 |
8 |
6 |
6 |
4 |
4 |
2 |
2 |
1 |
1 |
0 |
0 |
2/0 |
2/0 |
3/0 |
3/0 |
3/0 |
3/0 |
4/0 |
4/0 |
| 80 |
8 |
6 |
6 |
4 |
4 |
2 |
2 |
1 |
0 |
0 |
2/0 |
2/0 |
3/0 |
3/0 |
3/0 |
4/0 |
4/0 |
4/0 |
4/0 |
| 90 |
8 |
6 |
4 |
4 |
2 |
2 |
1 |
0 |
0 |
2/0 |
2/0 |
3/0 |
3/0 |
4/0 |
4/0 |
4/0 |
4/0 |
4/0 |
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| 100 |
6 |
6 |
4 |
4 |
2 |
2 |
1 |
0 |
2/0 |
2/0 |
3/0 |
3/0 |
4/0 |
4/0 |
4/0 |
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| . |
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CM = Circular mil area of conductor.
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Table X From ABYC E11 - CONDUCTORS SIZED FOR 10 PERCENT DROP IN VOLTAGE
Note: In the event of a conflict between the voltage drop table and the ampacity table use the larger wire size.
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| Length of Conductor from Source of Current to Device and Back to Source - Feet |
|
10 |
15 |
20 |
25 |
30 |
40 |
50 |
60 |
70 |
80 |
90 |
100 |
110 |
120 |
130 |
140 |
150 |
160 |
170 |
TOTAL
CURRENT
ON
CIRUIT
IN AMPS |
12 Volts - 10% Drop Wire Sizes (gauge) - Based on Minimum CM Area |
| 5 |
18 |
18 |
18 |
18 |
18 |
16 |
16 |
14 |
14 |
14 |
12 |
12 |
12 |
12 |
12 |
10 |
10 |
10 |
10 |
| 10 |
18 |
18 |
16 |
16 |
14 |
14 |
12 |
12 |
10 |
10 |
10 |
10 |
8 |
8 |
8 |
8 |
8 |
8 |
6 |
| 15 |
18 |
16 |
14 |
14 |
12 |
12 |
10 |
10 |
8 |
8 |
8 |
8 |
8 |
6 |
6 |
6 |
6 |
6 |
6 |
| 20 |
16 |
14 |
14 |
12 |
12 |
10 |
10 |
8 |
8 |
8 |
6 |
6 |
6 |
6 |
6 |
6 |
4 |
4 |
4 |
| 25 |
16 |
14 |
12 |
12 |
10 |
10 |
8 |
8 |
6 |
6 |
6 |
6 |
6 |
4 |
4 |
4 |
4 |
4 |
2 |
| 30 |
14 |
12 |
12 |
10 |
10 |
8 |
8 |
6 |
6 |
6 |
6 |
4 |
4 |
4 |
4 |
2 |
2 |
2 |
2 |
| 40 |
14 |
12 |
10 |
10 |
8 |
8 |
6 |
6 |
6 |
4 |
4 |
4 |
2 |
2 |
2 |
2 |
2 |
2 |
2 |
| 50 |
12 |
10 |
10 |
8 |
8 |
6 |
6 |
4 |
4 |
4 |
2 |
2 |
2 |
2 |
2 |
1 |
1 |
1 |
1 |
| 60 |
12 |
10 |
8 |
8 |
6 |
6 |
4 |
4 |
2 |
2 |
2 |
2 |
2 |
1 |
1 |
1 |
0 |
0 |
0 |
| 70 |
10 |
8 |
8 |
6 |
6 |
6 |
4 |
2 |
2 |
2 |
2 |
1 |
1 |
1 |
0 |
0 |
0 |
2/0 |
2/0 |
| 80 |
10 |
8 |
8 |
6 |
6 |
4 |
4 |
2 |
2 |
2 |
1 |
1 |
0 |
0 |
0 |
2/0 |
2/0 |
2/0 |
2/0 |
| 90 |
10 |
8 |
6 |
6 |
6 |
4 |
2 |
2 |
2 |
1 |
1 |
0 |
0 |
0 |
2/0 |
2/0 |
2/0 |
3/0 |
3/0 |
| 100 |
10 |
8 |
6 |
6 |
4 |
4 |
2 |
2 |
1 |
1 |
0 |
0 |
0 |
2/0 |
2/0 |
2/0 |
3/0 |
3/0 |
3/0 |
| . |
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| Length of Conductor from Source of Current to Device and Back to Source - Feet |
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10 |
15 |
20 |
25 |
30 |
40 |
50 |
60 |
70 |
80 |
90 |
100 |
110 |
120 |
130 |
140 |
150 |
160 |
170 |
TOTAL
CURRENT
ON
CIRUIT
IN AMPS |
24 Volts - 10% Drop Wire Sizes (gauge) - Based on Minimum CM Area |
| 5 |
18 |
18 |
18 |
18 |
18 |
18 |
18 |
18 |
16 |
16 |
16 |
16 |
14 |
14 |
14 |
14 |
14 |
14 |
12 |
| 10 |
18 |
18 |
18 |
18 |
18 |
16 |
16 |
14 |
14 |
14 |
12 |
12 |
12 |
12 |
12 |
10 |
10 |
10 |
10 |
| 15 |
18 |
18 |
18 |
18 |
16 |
14 |
14 |
12 |
12 |
12 |
10 |
10 |
10 |
10 |
10 |
8 |
8 |
8 |
8 |
| 20 |
18 |
18 |
16 |
16 |
14 |
14 |
12 |
12 |
10 |
10 |
10 |
10 |
8 |
8 |
8 |
8 |
8 |
8 |
6 |
| 25 |
18 |
16 |
16 |
16 |
14 |
12 |
12 |
10 |
10 |
10 |
8 |
8 |
8 |
8 |
8 |
6 |
6 |
6 |
6 |
| 30 |
18 |
16 |
14 |
14 |
12 |
12 |
10 |
10 |
8 |
8 |
8 |
8 |
8 |
6 |
6 |
6 |
6 |
6 |
6 |
| 40 |
16 |
14 |
14 |
14 |
12 |
10 |
10 |
8 |
8 |
8 |
6 |
6 |
6 |
6 |
6 |
6 |
4 |
4 |
4 |
| 50 |
16 |
14 |
12 |
12 |
10 |
10 |
8 |
8 |
6 |
6 |
6 |
6 |
6 |
4 |
4 |
4 |
4 |
4 |
2 |
| 60 |
14 |
12 |
12 |
12 |
10 |
8 |
8 |
6 |
6 |
6 |
6 |
4 |
4 |
4 |
4 |
2 |
2 |
2 |
2 |
| 70 |
14 |
12 |
10 |
10 |
8 |
8 |
6 |
6 |
6 |
6 |
4 |
4 |
4 |
2 |
2 |
2 |
2 |
2 |
2 |
| 80 |
14 |
12 |
10 |
10 |
8 |
8 |
6 |
6 |
6 |
4 |
4 |
4 |
2 |
2 |
2 |
2 |
2 |
2 |
2 |
| 90 |
12 |
10 |
10 |
8 |
8 |
6 |
6 |
6 |
4 |
4 |
4 |
2 |
2 |
2 |
2 |
2 |
2 |
1 |
1 |
| 100 |
12 |
10 |
10 |
8 |
8 |
6 |
6 |
4 |
4 |
4 |
2 |
2 |
2 |
2 |
2 |
1 |
1 |
1 |
1 |
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CM = Circular mil area of conductor.
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