Shore Power, Shore Risk: Auditing a Thames Berth for Electric Prestige Car Charging

At the 2026 London Yacht, Jet & Prestige Car Show, the language of integrated energy is fluent. Exhibitors present lithium systems, inverters, load-management modules and vehicle charge points as a single, seamless package. A Thames berth is less fluent. The question a buyer should carry from the show floor to the pontoon is not whether an electric prestige car can be charged beside a yacht, but what the supply, the certificate and the contract actually permit.

What the show floor promises

The show is a useful place to compare hardware. It is not a substitute for a site survey. A display stand can demonstrate a 22 kW charge point, a smart meter and a battery bank working in harmony because the stand has been designed for that purpose, with a known supply and a controlled load. A marina pedestal has been designed for a different purpose: intermittent domestic demand from moored vessels, often installed incrementally over decades.

That distinction matters for UK buyers. A prestige electric car with a 100 kWh battery is not a kettle. It may draw 7 kW for ten hours or more, and it may do so repeatedly. The berth that supports a yacht's shore power habit may not have the continuous duty rating, the protective devices or the contractual headroom for that pattern of use.

The pedestal is not a socket

A 32-amp single-phase supply at 230 volts equates to roughly 7.4 kW. That is a useful figure, but it is not a promise. Shore-power pedestals are frequently rated for 16 amps, sometimes for 32 amps and occasionally for 63 amps; the rating of the socket does not by itself confirm the capacity of the circuit behind it, the diversity allowance for the pontoon or the headroom at the marina's intake.

Three practical constraints emerge. First, continuous load: a charge point may run at its full rating for many hours, and older circuits may be thermally derated or subject to voltage drop over long cable runs. Second, earthing and protection: UK installations must satisfy BS 7671 and the IET's Code of Practice for Electric Vehicle Charging Equipment Installation, including appropriate residual current protection and, where required, PEN-fault protection. Third, metering: the marina may permit the connection but not the resale of electricity without a suitable sub-meter and billing arrangement.

A marina electrical upgrade is not a small matter. Additional capacity may require an application to the distribution network operator, landlord consent, new protective devices, certification and, in some London locations, physical works that are constrained by the pontoon structure. Buyers should treat any claim that a berth is 'EV-ready' as a starting point for inquiry, not a conclusion.

A four-stage audit before the cable

The first stage is the paper trail. Request the berth licence, the marina's electrical schematic, the latest inspection and testing certificate, the installation certificate for any charge point and the marina's insurance position on vehicle charging. If the marina cannot produce these documents, the conversation should not proceed to a quotation.

The second stage is capacity. Ask for the maximum demand calculation for the pontoon, the phase arrangement and the proposed charge point rating. Confirm whether the supply is single-phase or three-phase, whether load management will be fitted and what happens when the yacht and the car call for power at the same time.

The third stage is earthing and protection. The buyer does not need to become an electrician, but the buyer should ask who has confirmed the earthing arrangement, whether the charge point includes the required protection and who will issue the certificate on completion. A competent person should sign the work; a harbourmaster's verbal assurance is not a compliance document.

The fourth stage is metering and billing. Confirm how electricity will be measured, who reads the meter, what tariff applies and whether the berth licence permits the arrangement. A simple sub-meter and a clear monthly statement are preferable to an informal understanding.

Etiquette on a shared pontoon

Charging etiquette is not merely manners. On a shared pontoon, it is load management by another name. Buyers should expect to book charging windows, to accept a lower charge rate when the pontoon is busy and to avoid extension leads, daisy-chained adaptors or domestic sockets used outdoors. Those practices are neither safe nor likely to be permitted by a well-run marina.

The harbourmaster or marina manager should be treated as the authority for the berth. A polite written request, a clear charging plan and a named contact for faults will do more for a buyer's reputation than a larger charger. In London, where pontoons are often tight and access is constrained, the practical question of cable routing and fire-service access is as important as the electrical one.

The contract before the cable

Before any cable is laid, the buyer should establish several contractual points. Does the berth licence permit vehicle charging? Who owns and maintains the charge point? Who is liable for damage to the yacht, the car or a third party if the installation fails? Does the marina require notification for insurance purposes, and does the buyer's own policy respond? Who pays for an upgrade if the supply proves inadequate? What notice applies if the marina withdraws permission?

These questions are unglamorous, but they are the difference between an integrated energy system and an improvised one. The show floor can supply the hardware; the berth must supply the governance.

A buyer's checklist

• Obtain the berth's electrical schematic and maximum supply rating.
• Confirm single-phase or three-phase supply and the proposed charge point rating.
• Request the latest inspection and testing certificate and the charge point installation certificate.
• Confirm earthing arrangement and protective devices, including PEN-fault protection where required.
• Ask for the pontoon's maximum demand calculation and load-management plan.
• Confirm metering, tariff and billing arrangements in writing.
• Check the berth licence for permission to charge a vehicle.
• Notify the marina's insurer and the buyer's own insurer.
• Appoint a competent person to survey and certify the installation.
• Record the charging plan, fault contact and review date.

The question worth asking

The 2026 London Yacht, Jet & Prestige Car Show will show buyers what is technically possible. The Thames will show them what is practically permissible. The buyer who leaves the show with a checklist, rather than a cable, is the buyer most likely to enjoy both the yacht and the car without discovering the limits of the berth the hard way.