Electrical

Blue Sea · Victron · Ancor · BEP

Marine electrical: busbars, wire and power

Busbars and connectors, tinned Ancor and Pacer marine wire, circuit breakers, battery switches, Victron inverters, DC-DC chargers and ProMariner battery chargers for 12V and 24V boat systems.

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Marine electrical supplies

A boat's electrical system has to survive moisture, salt and vibration, and a bad connection can leave you without pumps or lights offshore. This is where we keep everything behind the helm: tinned marine wire, terminals, fuse blocks, circuit breakers, busbars, battery chargers, inverters and monitoring, from Blue Sea Systems, Victron Energy, Mastervolt, ProMariner, Newmar, Xantrex, Ancor, Pacer and Sea-Dog.

How to choose

  • Plan the circuits firstList every load and its amps, then size wire for the round-trip run so voltage drop stays low.
  • Protect every circuitEach positive wire needs a fuse or breaker close to the source, rated for the wire, not just the device.
  • Use marine-grade connectionsTinned wire and adhesive-lined heat-shrink terminals keep corrosion out of the joint.

Wiring a new helm is what we do every day. We build pre-wired custom switch panels with breakers, Deutsch connectors and a printed wiring diagram. Read how to wire a switch panel, or call or WhatsApp (407) 543-8691.

Frequently Asked Questions

What is a busbar and do I need one?
A busbar is a solid copper or tinned bar that joins many positive or negative wires at one point. It replaces stacks of ring terminals on a battery post and keeps the wiring clean, cool and easy to trace.
How do I choose a busbar connector?
Match the busbar's amp rating to the total current it will carry, and the stud or screw size to your ring terminals. High-current main busbars such as the Blue Sea PowerBar or BEP Pro Installer use 3/8" studs; smaller common busbars use screw terminals.
What does a DC-DC converter or charger do?
A DC-DC converter changes one DC voltage to another, for example 24V to 12V. A DC-DC charger such as the Victron Orion XS also charges a second battery, including lithium, from the alternator without overloading it.
What is tinned marine wire and why use it?
Tinned wire has every copper strand coated in tin, which resists the corrosion that spreads through bare copper in salt air. Ancor and Pacer tinned marine wire is the standard for boat wiring.
What wire size do I need?

It depends on the current and the round-trip length of the circuit. Size the wire so voltage drop stays under 3% for critical loads such as navigation lights and pumps, and under 10% for general loads.

Typical tinned wire sizes for 12V accessories on runs under about 20 ft round trip:

Load Typical gauge
Bilge pumps 12 AWG
Courtesy, cockpit and LED accent lights 14–16 AWG
Navigation and anchor lights 14–16 AWG
Spreader lights and small LED light bars 14 AWG
Livewell and baitwell pumps 12–14 AWG
Washdown and freshwater pumps 10–12 AWG
Horn 14 AWG
Stereo head unit 12–14 AWG
Trim tabs 12–14 AWG
Speakers 16 AWG

Use heavier wire for longer runs, and always check the manufacturer's spec and fuse the circuit to match the wire.

Should I use a fuse or a circuit breaker?
Both protect the wire. A breaker, including panel-mount breakers such as the Blue Sea 187 series, can be reset without spares, while a fuse is compact and inexpensive. Either one should be rated for the wire and installed as close to the power source as possible.
What size battery charger do I need?
Choose a charger with one output per battery bank. For lead-acid banks, a charge rate of about 10 to 20% of the bank's amp-hour capacity is typical; lithium batteries need a charger with a lithium profile.
Inverter or inverter/charger?
An inverter turns DC battery power into AC power. An inverter/charger, such as the Victron MultiPlus, also charges the batteries and switches to shore power automatically when you plug in.