Shore power safety

Shore power turns a boat into a small floating home: batteries stay charged, the fridge stays cold and you can run tools, heaters and air conditioning without the engine or generator. It also brings mains electricity into a wet, salty, moving environment where people are often barefoot. That combination needs respect. This guide explains the basics of using marina power safely, the role of residual current devices (RCDs), how to look after leads and plugs, and when to call a professional. It's general information, not electrical advice: all fixed wiring work must be done by a licensed electrician.

Why shore power needs care

Electricity and water don't mix. On a boat, damaged leads, corroded connectors, water in sockets and faulty wiring can all create a path for current to flow where it shouldn't, through metal fittings, through the water, or through a person. The Australian Maritime Safety Authority points out that the risk of injury or death increases when electrical equipment and wiring is damaged or used in wet surroundings.

AMSA's own example is sobering: a deckhand on a fishing vessel was electrocuted while using a 240-volt angle grinder on an extension lead from a socket that wasn't protected by an RCD. A wave wet the grinder and plug. The coroner agreed that if an RCD had been fitted, he may not have died.

What an RCD does

An RCD, sometimes called a safety switch, constantly compares the current flowing out on the active wire with the current returning on the neutral. If some current is leaking to earth, for example through a person, the RCD switches off the power almost instantly. AMSA explains that RCDs are designed to immediately switch off the supply when electricity leaks to earth at a level that is harmful to a person.

On a boat you might have RCD protection in several places:

• at the marina's power pedestal;
• in your boat's main switchboard, protecting onboard circuits;
• in portable RCD units or power boards for tools and appliances.

For owners and operators of domestic commercial vessels, AMSA says RCDs must be used whenever 240-volt supplies are in use, as part of their general safety duties under the national law. Even on a private boat, having RCD protection on every 240-volt circuit is sensible.

Testing RCDs

An RCD you've never tested is an RCD you hope works. AMSA's guidance for domestic commercial vessels is:

• RCDs must be inspected and tested every 12 months, under state and territory laws, by a competent person such as a licensed electrician, an accredited marine surveyor or a person trained to use an RCD tester;
• a push-button test every three months for portable RCDs and every six months for fixed RCDs, which any crew member can do;
• keep a record of testing until the device is next tested or disposed of.

For a private boat, following the same schedule is good practice. Pressing the test button should trip the RCD and cut the power. If it doesn't trip, stop using that circuit and get it checked.

Leads and plugs

Your shore power lead is the weak link. It's dragged across pontoons, stepped on, left in the sun and dunked in water.

• Use a lead and connectors designed for marine shore power, of the right rating for your boat and the marina's supply.
• Check the lead every time you use it. Look for cuts, crushed sections, exposed inner cores, scorching, loose plugs or green corrosion on pins.
• Keep plugs and sockets dry and fit caps or covers when they're not in use.
• Don't join leads together to make them longer, and don't use household extension cords or double adaptors.
• Route the lead so it can't fall in the water, get trapped between the boat and pontoon, or trip someone. Leave a little slack for the boat to move.
• Replace damaged leads; don't tape them up.

Your marina may have its own rules for shore power leads, such as requiring periodic testing and tagging. Ask, and follow them.

Connecting and disconnecting

A safe routine:

1. Switch off the boat's main shore power breaker and the pedestal outlet.
2. Connect the lead to the boat first.
3. Connect the other end to the pedestal.
4. Switch on at the pedestal, then on the boat.
5. Press the RCD test button if appropriate, and reset.

To disconnect, reverse the steps: switch off on the boat and at the pedestal, unplug at the pedestal first, then at the boat. That way you're never holding a live plug near the water.

Signs something is wrong

Stop using shore power and get an electrician if:

• an RCD or breaker trips repeatedly;
• plugs or sockets feel warm, smell hot or look discoloured;
• you feel a tingle touching metal fittings, ladders or rails;
• zinc anodes are wasting unusually fast, which can point to stray current;
• lights flicker or appliances behave strangely.

Never ignore a tingle. It means current is going where it shouldn't.

Swimming near boats with power

Faulty electrics on boats or marina docks can leak current into the water, which can incapacitate swimmers. Many marinas ban swimming for this and other reasons. Follow your marina's rules, keep children and pets out of the water around powered pontoons, and never dive in to rescue someone near a live supply without first having the power switched off, if it's safe to do so. Call for help and throw a flotation device.

Severe weather and leaving the boat

Before a storm or cyclone, Get Ready Queensland advises disconnecting shore power. Rising water, spray and moving boats can damage leads and pedestals. Make sure your batteries are charged enough to run bilge pumps through the storm. See our guide to preparing for severe weather.

When you leave the boat for a while, decide what needs to stay powered. A battery charger may need shore power, but heaters and other appliances shouldn't be left running unattended.

Working on your electrics

Owners can do plenty of routine checks, but fixed 240-volt wiring is regulated work for licensed electricians in every state. For boats, look for an electrician with marine experience who understands corrosion, isolation, earthing and the standards that apply to boats. AMSA notes that RCDs fitted to isolated earthing systems need specific testing procedures, which is a good example of why expertise matters.

A quick pre-connection check

Before every connection, look at the pedestal and your lead, keep plugs dry, switch off first, connect boat then pedestal, switch on and test the RCD. It takes less than a minute.

Key points

• Shore power brings mains electricity into a wet environment; treat it with respect.
• RCDs cut power when current leaks to earth; test them regularly.
• Use marine-rated leads in good condition and never improvise with household cords.
• Connect boat end first, pedestal last; disconnect in reverse.
• Never ignore tingles or repeated trips, and leave fixed wiring to licensed electricians.