Blue Sea Systems 8280 Traditional Metal Dual Bank Battery Management Panel - Manual (Page 2)

Wire Sizing Chart
1. Calculate the maximum sustained amperage of the circuit. Measure the
length of the circuit from the power source to the load and back.
2. Calculate Famps (Feet x amps). Multiply circuit lenght by max. current.
3. Base the wire on either the 3% or 10% voltage drop. In general, items
that affect the safe operation of the boat and its passengers (running
lights, bilge blowers, electronics) use 3%; all other loads use 10%.
4. Are the circuit runs in an engine space or non-engine space?
5. Starting in the column that has the right voltage and voltage drop,
select a value that is greater than the calculated Famps. Look left to the
Ampacity column to verify that the total amperage of the circiut does
not exceed the maximum allowable amperage of the wire size for
that row. If it does, move down until the wire ampacity exceeds the
circuit amperage. Finally, look left to the wire size column to select the
wire size.
Note: For wire with 105°C insulation rating and AWG wire sizes.
Chart courtesy of the West Advisor
Wiring Diagram
DC Battery Switch Panel
PN 8370
ENGINE HOUSE ENGINE HOUSE
Wiring Diagram
DC Battery Switch Panel
PN 8280
Example
A 12 volt system at 10% drop with a 40’ circuit x 45 amps = 1800 Famps.
A wire size of 8 is required.