ABYC E-11 • DC Voltage Drop & AWG Sizing
Marine Wire Size & Voltage Drop Calculator
Size your DC cables safely to prevent overheating, fire hazards, and power loss on 12V, 24V, 36V, and 48V boat, trolling motor, and campervan setups.
⚡ ABYC E-11 Standard
DC Wire Size (AWG) & Voltage Drop Calculator
Marine Grade Tinned Copper (BC-5W2)
50 Amps
5A30A50A (Standard)100A150A
15 Feet
💡 Crucial: Measure distance from battery to appliance and BACK (Positive wire + Negative wire).
Recommended Cable Size (AWG)
--Tinned Copper
Actual Voltage Drop:-- V (--%)
Voltage at Motor:-- V
Power Wasted (Heat):-- Watts
Min. Circular Mils:-- CM
⚓ ABYC Standards Quick Check
Calculating electrical specs...
How Marine DC Voltage Drop is Calculated
In 12V and low-voltage DC marine circuits, resistance is significantly more critical than in 120V household AC. The standard formula uses Circular Mils (CM):
Circular Mils (CM) = (K × Current in Amps × Total Round-Trip Feet) ÷ Allowable Voltage Drop (Volts)
Where K = 10.75 (the constant resistance of marine tinned copper wire at 75°C). The calculated circular mil value is then cross-referenced with standard American Wire Gauge (AWG) tables.
ABYC DC Cable Ampacity & Resistance Chart
| AWG Size | Circular Mils | Resistance (Ω / 1000 ft) | Max Ampacity (Engine Room) | Max Ampacity (Outside Engine) |
|---|---|---|---|---|
| 16 AWG | 2,580 | 4.99 | 21A | 25A |
| 14 AWG | 4,110 | 3.07 | 30A | 35A |
| 12 AWG | 6,530 | 1.93 | 38A | 45A |
| 10 AWG | 10,380 | 1.21 | 51A | 60A |
| 8 AWG | 16,510 | 0.764 | 68A | 80A |
| 6 AWG | 26,240 | 0.481 | 102A | 120A |
| 4 AWG | 41,740 | 0.302 | 136A | 160A |
| 2 AWG | 66,360 | 0.190 | 178A | 210A |