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Wire Size Calculator
Wire Size Calculator
Wire length is the total length of the wire from the power source (battery) to the appliance and back to the power source.
Amps drawn from the appliance should be obtained from the manufacturer's specifications.
Installation in Engine Compartment
Wires installed in engine compartments experience higher temperatures and require upsizing to meet ABYC standards.
3% voltage drop on critical appliances - Critical appliances with no more than 3% voltage drop. This could be navigational equipment, navigational lights, VHF radio, radar, autopilot, and such.
3% voltage drop on semi-critical appliances - Semi-critical equipment are those not critical to sailing but critical to the electrical system. This could include heaters, refrigerators, and such, where there is a higher startup load which drops shortly after startup.
10% voltage drop on non-critical appliances - Non-critical appliances could include your stereo, cabin lights, USB chargers, and such. These are appliances you can spare even when the system is overloaded.
All calculations are based on the use of marine-grade multistranded tinned copper wire with a resistance of 0.0175 ohms per meter per mm² of cross-sectional area. The use of a different type of conductor will influence the voltage drop.
Calculations do not take simultaneous or parallel factors into account. These you have to apply yourself.
Cable/Wire length should be meassured from the power source to the appliance and back. A full circuit
3% voltage drop on semi-critical appliances - Semi-critical equipment are those not critical to sailing but critical to the electrical system. This could include heaters, refrigerators, and such, where there is a higher startup load which drops shortly after startup.
10% voltage drop on non-critical appliances - Non-critical appliances could include your stereo, cabin lights, USB chargers, and such. These are appliances you can spare even when the system is overloaded.
All calculations are based on the use of marine-grade multistranded tinned copper wire with a resistance of 0.0175 ohms per meter per mm² of cross-sectional area. The use of a different type of conductor will influence the voltage drop.
Calculations do not take simultaneous or parallel factors into account. These you have to apply yourself.
Cable/Wire length should be meassured from the power source to the appliance and back. A full circuit
Disclaimer: Always use the recommended wire size provided by the manufacturer of the equipment for the most accurate and safe results.
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