Table F: Allowable Amperage of Conductors of 50 Volts or More
The Tables do not consider voltage drop for conductors under
50 volts. The values shown on the ampacity table are the maximum safe amperages
which the conductor can carry on a continuous basis. They do not apply to
intermittent starting loads such as motor start currents. Since all
Boat Cable is 105° C insulated, only that
temperature rating is shown. Due to the higher ambient temperatures in engine
spaces and the heat retention of large wire bundles, a “correction factor” must
be used to derate the wire by increasing conductor size. Table F takes into
consideration these factors and should be used to select conductor sizes for
circuits over 50 volts. Note that for electrical systems under 50 volts, voltage
drop is the controlling factor and the tables on pages 14 and 15 should be used.
*There is NO LIMIT on conductors in a bundle under 50 Volts.
- Note: These tables only apply for 105° C (221° F) wire and
other premium wire and should not be used for lesser grades of wire and cable.
- Reprinted at the courtesy of the United States Coast Guard
Electrical System Compliance Guideline.
|
2 Conductors 105° C (221° F) |
3 Conductors 105° C (221° F) |
4 to 6
Conductors 105° C (221° F) |
7 to 24
Conductors 105° C (221° F) |
Conductor |
Outside |
Inside |
Outside |
Inside |
Outside |
Inside |
Outside |
Inside |
Size |
Engine |
Engine |
Engine |
Engine |
(AWG) |
Space |
Space |
Space |
Space |
18
|
20 |
17.0 |
14.0 |
11.9 |
12.0 |
10.2 |
10.0 |
8.5 |
16
|
25 |
21.3 |
17.5 |
14.9 |
15.0 |
12.8 |
12.5 |
10.6 |
14
|
35 |
29.8 |
24.5 |
20.8 |
21.0 |
17.9 |
17.5 |
14.9 |
12
|
45 |
38/3 |
31/5 |
26.8 |
27.0 |
23.0 |
22.5 |
19.1 |
10
|
60 |
51.0 |
42.0 |
35.7 |
36.0 |
30.6 |
30.0 |
25.5 |
8
|
80 |
68.0 |
56.0 |
47.6 |
48.0 |
40.8 |
40.0 |
34.0 |
6
|
120 |
102.0 |
84.0 |
71.4 |
72 |
61.2 |
60.0 |
51.0 |
4
|
160 |
136.0 |
112.0 |
95.2 |
96.0 |
81.6 |
80.0 |
68.0 |
3
|
180 |
153.0 |
126.0 |
107.1 |
108.0 |
91.8 |
90.0 |
76.5 |
2
|
210 |
178.5 |
147.0 |
125.0 |
126.0 |
107.1 |
105.0 |
89.3 |
1
|
245 |
208.3 |
171.5 |
145.8 |
147.0 |
125.0 |
122.5 |
104.1 |
1/0
|
285 |
242.3 |
199.5 |
169.6 |
171.0 |
145.4 |
142.5 |
121.1 |
2/0
|
330 |
280.5 |
231.0 |
196.4 |
198.0 |
168.3 |
165.0 |
140.3 |
3/0
|
385 |
327.3 |
269.5 |
229.1 |
231.0 |
196.4 |
192.5 |
163.6 |
4/0
|
445 |
378.3 |
311.5 |
264.8 |
267.0 |
227.0 |
222.5 |
189.1 |
|