Electrical system

How to choose the components for the onboard electrical system

Marine electrical cables: cross-section and insulation

Cables intended for marine use must withstand moisture, vibration, and salt spray: super-insulated PVC insulation and tinned copper conductivity are basic requirements. The cross-section must be sized based on the maximum current of the circuit and the length of the run, to contain the voltage drop. For power circuits such as the anchor windlass, generous cross-sections are required; for instrumentation or courtesy lights, smaller cross-sections are sufficient.

Fuses and protection: ANL, ATO/ATC, AMI/MIDI and glass

The choice of fuse depends on the rated current of the circuit and the type of fuse holder already on board. ANL fuses are used on high-current circuits such as the main battery cables; ATO/ATC and AMI/MIDI cover auxiliary circuits and multiple distribution panels. Glass fuses remain common in older installations. Blue Sea and Quick offer fuse holders and fuses designed specifically for the marine environment.

Switches and battery disconnects

Magneto-hydraulic circuit breakers protect without degrading with the temperature variations typical of the marine environment. The two-pole battery disconnect completely isolates the system when the boat is not in use, preventing accidental discharges and short-circuit risks. Blue Sea, Osculati and Egis offer solutions for different rated currents and battery configurations.

Navigation lights, lanterns and LED lighting

Navigation lights must comply with navigation regulations based on the length of the vessel and the type of use. LED lanterns reduce consumption compared to incandescent versions and extend the life of the optics. For interior lighting, stainless steel ceiling lights with polycarbonate lenses are suitable for the humid environment; Hella Marine courtesy lights are among the most sought-after products for passageways. Underwater LED lights for stern mirrors and hulls require watertight connections and materials resistant to galvanic corrosion.

Batteries, battery chargers and inverters

Onboard power management involves choosing the type of battery (AGM, gel, lithium), the Ah capacity appropriate for actual consumption, and a battery charger compatible with the battery chemistry. Victron Energy and Mastervolt are established references for multi-stage battery chargers and inverters. A battery test panel allows monitoring of the state of charge; the battery box mechanically protects the battery from moving while sailing.