Shore Power Installation for Boats
Shore power brings 230V from the pontoon to the boat, to charge the batteries and run sockets, heating and appliances while you are berthed. Because it is mains voltage on a boat surrounded by water, it has to be installed properly. We fit and upgrade shore power systems from the inlet to the charger, test them and give you a written quote first.
A shore power system is a short chain: the shore power cable from the pedestal, a weatherproof inlet on the boat, protection in the form of an RCD and circuit breakers, an AC distribution panel, and the circuits it feeds, usually including a battery charger. Many installations also include a galvanic isolator in the earth to reduce corrosion.
Older boats often have shore power added in stages, with a domestic-style consumer unit, an extension lead through a hatch or no galvanic protection. Systems like these are worth bringing up to a proper marine standard.
What a shore power installation includes
Each part has a job, and the system is only as good as its weakest connection.
- A marine shore power inlet, mounted where the cable will not be strained
- Double-pole RCD protection and breakers for each AC circuit
- An AC panel with labelled circuits
- A galvanic isolator or isolation transformer where suitable
- A battery charger, or a Victron inverter-charger, set to the battery type
- Polarity and RCD tests before handover
Shore power, chargers and inverters
On many boats the shore power feeds a battery charger, which keeps the bank healthy while berthed. Where an inverter is fitted, the two must never feed the same circuits at once. An inverter-charger such as a Victron MultiPlus handles this with a built-in transfer switch, passing shore power through when it is available and inverting from the batteries when it is not. A standalone inverter needs a proper changeover arrangement instead of a plug that can be swapped by hand.
Marine inverter installation · Boat battery charging
Galvanic protection on shore power
Plugging into shore power connects your boat's earth to every other boat on the pontoon. Small currents can then flow through the water and attack underwater metals. A galvanic isolator in the earth line blocks those low voltages while still providing a safety earth; an isolation transformer separates the boat from shore entirely. Which suits depends on the boat, its berth and its other equipment.
Marine bonding and galvanic isolators
When shore power keeps tripping
An RCD that trips is doing its job. The cause might be moisture in an inlet or socket, a faulty appliance, an immersion heater element breaking down, or an earth fault on one circuit. We isolate circuits one by one to find the source, rather than replacing the RCD and hoping. Our guides on shore power installation and RCD tripping explain more.
Shore power installation guide · Shore power tripping the RCD
Frequently asked questions
Why is shore power not charging my battery?
The charger may be switched off, tripped, faulty or set to the wrong battery type, or there may be no supply reaching it from the pedestal or inlet. Testing along the chain finds which.
Why does my shore power keep tripping?
Usually moisture, a faulty appliance or an earth fault on one circuit. Circuits are isolated in turn until the cause is found.
Can I plug shore power into my inverter?
Only an inverter-charger designed to accept an AC input, such as a MultiPlus. A plain inverter must never be fed from shore power; it needs a proper changeover.
Can I use shore power without a battery?
AC circuits fed directly from the shore supply will work, but a boat's 12V system and many chargers expect a battery to be connected. It is not a good way to run a boat.
Why is it called shore power?
Because the electricity comes from the shore, through the marina pedestal, rather than from the boat's own batteries or generator.
Install or upgrade shore power
Tell us the boat, what is fitted now and where it is berthed, and we will arrange an assessment and written quote.