Shore Power Changeover Pre-Arrival Checklist

Shore power is not just a large plug. It is a transfer between the yacht's electrical plant and a shore-side supply that may have different limits, protection settings, earth arrangements, voltage quality, frequency expectations, phase sequence and load capacity.

When it goes wrong, the result can be nuisance trips, blackouts, overheated cables, damaged plugs, unstable converters, unhappy marinas, guest discomfort, or a long argument about whether the yacht or the berth caused the problem.

The best shore-power changeover starts before the lines are made fast.

Applicability depends on vessel size, shore-power voltage, frequency, current demand, transformer/converter arrangement, marina infrastructure, class/flag requirements, local electrical rules, whether the yacht uses low-voltage or high-voltage shore connection, and whether the transfer is routine, temporary or yard-period power.

Follow the yacht's approved procedures and only allow competent personnel to connect or operate shore-power equipment.

Before arrival, confirm:

• available voltage,
• frequency,
• phase arrangement,
• maximum current,
• socket/connection type,
• cable requirement,
• shore-side protection,
• whether a converter is required,
• whether parallel shore supplies are allowed,
• marina contact,
• local restrictions on generator running,
• expected hotel load on arrival.

If the marina cannot support the expected load, plan load shedding before arrival, not after trips start.

High-load systems may include:

• chillers and HVAC,
• galley,
• laundry,
• battery chargers,
• stabilisers,
• watermakers,
• AV/IT racks,
• lighting,
• spa or pool systems,
• tender and toy chargers.

Reduce non-essential loads before transfer. Do not let the first test of marina capacity happen when guests are onboard and the galley, laundry and chillers are all running.

Before connection:

• inspect cable jacket,
• inspect plug/socket condition,
• check strain relief,
• keep cables clear of traffic and water traps,
• confirm cable rating,
• confirm cable routing,
• confirm no heat damage,
• confirm connection area is controlled.

Poor cable management is a fault source and a safety issue.

Not every shore-power issue appears immediately at the pedestal. Some faults show up only after the yacht has been connected for a while and the hotel load increases.

Watch for:

• cable or plug heating,
• phase imbalance,
• voltage sag when chillers start,
• converter warnings,
• transformer temperature alarms,
• earth-fault or insulation alarms,
• unexpected generator standby start,
• PMS load-limit warnings,
• nuisance trips after guest areas wake up.

These symptoms should be recorded with load data. A simple note saying "shore power tripped" is not enough to distinguish a marina supply problem, yacht overload, cable issue, converter fault or protection setting issue.

Shore-power transfer should have a named communication path. The engineer or ETO should know who is speaking to the marina or yard, and the bridge should know when power source changes are about to happen.

Useful callouts include:

• "Preparing to connect shore power."
• "Reducing hotel load for transfer."
• "Testing supply."
• "Shore power connected, monitoring load."
• "Supply unstable, returning to generator."

Clear communication prevents the interior, galley or AV team from starting large loads during the most sensitive part of the transfer.

1. Confirm shore supply details with marina or yard.
2. Confirm yacht electrical configuration and required current.
3. Reduce non-essential loads.
4. Notify bridge and affected departments.
5. Inspect cable, plug, inlet and shore pedestal.
6. Confirm voltage, frequency and phase sequence where applicable.
7. Confirm earth/protection status according to procedure.
8. Confirm converter or transformer status.
9. Prepare PMS or switchboard transfer mode.
10. Connect according to yacht procedure.
11. Monitor voltage, frequency, current and alarms after transfer.
12. Increase loads gradually.
13. Record supply details, load, alarms and any limitations.

For the first 30 minutes, monitor:

• current per phase,
• voltage stability,
• frequency,
• transformer or converter alarms,
• cable temperature where appropriate,
• breaker status,
• PMS alarms,
• generator standby status,
• hotel-load behaviour.

If the supply trips, do not repeatedly reset. Record what happened, reduce load, check protection indication and speak to the marina or yard.

A yacht arrives after a hot passage. Chillers are loaded, battery chargers are active, laundry starts, and the chef begins prep. Shore power connects, holds for ten minutes, then trips. The crew resets twice. The marina blames the yacht. The yacht blames the marina.

The useful evidence is current demand, phase balance, loads active, shore limit, trip indication, converter alarms and whether the yacht staged the load. Without that, the discussion becomes guesswork.