Electrical systems are the least visible and most litigated part of a custom build. Nobody photographs a cable tray, but wiring faults cause more yacht fires than any other single source, and voltage mismatch is the classic headache of a boat built on one continent and cruised on another. This article explains how a classed Indonesian new build gets electricity right from the first drawing.
Two Voltages, One Honest Architecture
The wrong way to build a world-cruising yacht is to pick one shore standard and hope. The right way is to decide what actually needs alternating current. Modern practice pushes lighting, navigation, refrigeration and pumps onto a robust 24V DC backbone charged from multiple sources; AC then serves heavy hotel loads — air-conditioning, galley, laundry — through a distribution that accepts either shore world. Two proven routes: an isolation transformer with tap switching, which also breaks galvanic paths at the dock, or a charger–inverter front end that treats shore power purely as energy input and re-manufactures clean AC aboard. Frequency-sensitive motors are specified 50/60Hz-tolerant or avoided.
This architecture is decided alongside the engine room layout, because alternator capacity, generator sizing and battery placement are one conversation, not three.
What Class Survey Actually Checks
Bureau Veritas and RINA electrical rules read like common sense enforced with paperwork: cable sized for load and voltage drop with marine-grade tinned conductors, circuit protection coordinated so faults trip locally, bilge-adjacent equipment rated for the environment, and separation between high and low voltage runs. The surveyor walks cable trays before liners close them in — one of the hold points owners should attend, as we note in our engineering series — and insulation-resistance tests are recorded per circuit before energising.
Documentation is half the value of a classed build. Every breaker, bus and cable run appears in as-built drawings handed over at delivery. Ten years later, an electrician in any country can service the vessel without archaeology. That file is also what surveyors verify during the harbour and sea acceptance programme described in our article on sea trials for metal yachts.
Batteries, Chargers and the Lithium Question
Lithium iron phosphate banks are now the default request on new builds, and class societies have caught up with formal requirements: battery management systems with external shutdown, thermal runaway containment, charging sources coordinated through the BMS rather than around it. We install lithium under those rules or build a premium lead-carbon system where an owner prefers simplicity — both honest choices at different points on the cost–capability curve.
Charging redundancy follows expedition logic even on coastal boats: engine alternators with external regulation, generator-driven chargers, and solar sized to hold the DC backbone at anchor. On aluminium hulls the stakes rise — stray DC current that merely wastes energy on a steel boat can eat an alloy hull at a through-fitting, which is why our aluminium building program pairs every electrical drawing with a bonding and isolation plan.
Owner-Supplied Electronics, Integrated Properly
Most owners supply their own navigation and entertainment electronics, and we encourage it — with the integration discipline described in our guide to owner-supplied equipment. Model numbers frozen early, power requirements confirmed against the DC budget, and network topology drawn before the helm console is built. Equipment wired for a single voltage world gets flagged at specification stage, when the fix costs a part number rather than a rebuild.
Frequently Asked Questions
Can an Indonesian-built yacht use shore power in both Europe and the USA?
Yes, when designed for it: an isolation transformer with voltage taps or a charger–inverter front end lets the vessel accept 230V/50Hz and 120V/60Hz docks without adapters or drama. The decision is architectural and belongs in the specification before the first cable is drawn.
What electrical standards apply to a classed build in Indonesia?
The classification society’s electrical rules — Bureau Veritas or RINA on our builds — govern cable sizing, protection, installation and testing, with survey checks before compartments close and recorded insulation tests before energising. The as-built electrical file is handed to the owner at delivery.
Do you install lithium battery systems?
Yes, engineered to class requirements: managed cells with external shutdown, coordinated charging sources and thermal containment. Where an owner prefers proven simplicity, a lead-carbon bank remains a respectable choice, and we price both without pushing either.
Why does wiring matter more on an aluminium hull?
Because stray DC current corrodes aluminium aggressively at any point where it exits the hull into seawater. Alloy builds carry a full bonding and isolation plan, galvanic isolation on shore connections and strict separation of DC negatives from the hull — engineering that must be designed in, not retrofitted.
Specify the Electricity Before the Steel
Send us your cruising plans and equipment list, and our design office will answer with a distribution architecture and DC budget that fits them — the same systems engineering our parent group applies across its boat construction division. WhatsApp +62 811-3941-4563 or email [email protected].