HOW TO SELECT GAUGE OF CABLE REQUIRED
Table 1 has been formulated to indicate the maximum circuit length in feet before a voltage drop of 1/2 volt is reached in a 6 volt system.

EXAMPLE:

Assume that six-volt lamp circuit is 23 feet in total length and requires 7.5 amperes. Read across the 6-volt system line (Table I) to 7.5 amperes. Then read down to the first figure in Table II that is greater than the 23 feet required; this figure is 24 feet. Now read directly to the left, from 24 feet (on the same line), and you will find 14 gauge conductor adequate for this application.

NOTE:

Since this table is based on a 1/2-volt drop allowance; specific drops can be easily determined by the following:
For a 1/8 volt-drop—Divide Table I allowable lengths by four.
For a 1/4 volt-drop—Divide Table I allowable lengths by two.
For a 1 volt-drop—Multiply Table I allowable lengths by two.
For a 2 volt-drop—Multiply Table I allowable lengths by four.
gauge-sheet-table1

Wire gauge usage in light blue shaded area not recommended for 12-volt system.
Wire gauge usage beyond yellow – blue shaded area (solid line on PDF printout/download)
not recommended for 24-volt system.
In either case for amperage load use the next larger gauge below the shaded area or solid line.

gauge-sheet-table2