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If you know little or nothing about electrical circuits go to,
Basic Electricity 1  2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
US Navy Basic Electricity Course  or  The Complete Basic Electricity and Electronics Course
Contact ABYC and the Coast Guard to get the latest standards for Electrical systems.
 Info about ABYC Standards

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ELECTRICAL SYSTEM - Voltage Drop

Electrical regulations and standards that apply to boat builders and recreational boats.  Calculating Voltage Drop .

This table is from ABYC standards. There are tables for 24 volts and 32 volts, and for AC systems, in the ABYC Electrical Standard E-11.  Contact ABYC for a copy of E-11, AC and DC Electrical Systems on Boats.

Table to determine wire size due to voltage drop based on the length of the wire. This table is for 12 volts only.

Length of conductor from power source to the device and back to the power source

Feet 10 15 20 25 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170
Total Amps 12 volt  -  10% drop wire sizes gauge
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 4 4 4 4
25 16 14 12 12 10 10 8 8 8 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 2/0 3/0 3/0
American Boat And Yacht Council  Boat Design Net  Wooden Boat Foundation
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