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Orion Marine
Marine Electrical

Marine Electrical Testing & Commissioning

How do you know an electrical job is finished and ready for controlled energisation? A new, modified or repaired system is checked with the circuit dead, energised in a controlled order, proven function by function and then run under the load it was installed for.

Why test before energisation

Find wiring and setting errors before they become live faults

Common commissioning defects include a core on the wrong terminal, damaged insulation, a missing link or a setting that was never entered. Dead checks are intended to find those problems before energisation, when correcting them is safer and less disruptive than discovering them under power.

Commissioning is also where the work meets the rest of the vessel. A new starter can be wired correctly and still refuse to start because a permissive from another system is missing. Faults of that kind only appear when the equipment is operated with the systems around it, which is why commissioning continues into functional and loaded tests.

Commissioning sequence

Five stages from dead checks to handover

Each stage is completed and recorded before the next begins. If a stage fails, the fault is corrected and that stage is repeated before the sequence continues.

  1. 01

    Before energisation

    Checks with the circuit dead

    Visual inspection against the drawings. Continuity and core identification on new cables, insulation resistance between conductors and to earth, termination checks, earthing and bonding. Protection settings are entered and compared with the setting list.

  2. 02

    First energisation

    Power applied in a controlled order

    Circuits are energised in a controlled sequence from the supply side, with downstream breakers open. Voltage and phase sequence are confirmed at each stage, with polarity checked where relevant, before the next part of the circuit is brought live. Control supplies are established before the associated power circuits.

  3. 03

    Functional test

    Controls, alarms, protection, interlocks

    Each start, stop and changeover is operated from the relevant control positions. Alarms are raised at source and checked at the monitoring system. Interlocks are tested against the action they are intended to prevent, and trips are function-tested to confirm that the intended breaker opens.

  4. 04

    Under load

    Run in the condition it was installed for

    Motors are checked for direction of rotation, then run with their load connected while current, voltage and operating condition are observed. Drives are taken through the required speed range. Generators are run in parallel and load sharing is checked through load changes.

  5. 05

    Handover

    Results and documents left on board

    Measured values, final settings and completed tests are recorded and handed over. Where the work changed the installation, the drawings are marked up to match the as-fitted condition. Any open points are listed with the action still required and who is responsible for closing them.

Scope of testing

The tests depend on what was changed

A new feeder is tested differently from a replaced drive or a repaired generator control circuit. The scope is agreed before the work starts: which tests, the acceptance value for each, and who witnesses them.

Where the work requires class approval, the test results and marked-up drawings are prepared for submission to the vessel's class society. The survey and certification remain with class; our role is to have the system and supporting records ready for review.

Testing can also be a job in its own right. After a repair, blackout or long lay-up, an owner may want the condition of an installation established before it returns to service. Insulation-resistance readings taken at that point can then serve as a reference for later checks.

Where it applies

Work that needs testing and commissioning

The commissioning sequence is applied to each of these according to what was installed, repaired or changed.

Conditions for loaded tests

What has to be available for testing

Loaded and functional tests depend on the vessel being ready to operate the equipment as much as on the commissioning team.

  • The system available for testing and safe to operate
  • Load to run against: cargo gear, pumps, hotel load
  • Crew to operate machinery outside our scope
  • Time in the schedule for rectification and retesting
  • The class surveyor's attendance where a survey is required
Related work

Work that ends with testing and commissioning

FAQ

Before commissioning starts

Does every job end with the full sequence?
The sequence is the same, but the scope is not. A like-for-like breaker replacement may need only a limited set of checks; a new switchboard section can require all five stages. The test scope follows what was changed and what depends on it.
What happens when a test fails?
The fault is found and corrected, and the failed stage is repeated from its start. A circuit is not energised on the strength of a test it has not passed. The schedule should allow time for rectification and retesting, especially where the as-fitted condition differs from the drawings.
Do you issue class certificates?
No. Certification and survey belong to the vessel's class society. We prepare the test records and marked-up drawings required for review and attend where our work is being witnessed.

Need to commission a new or modified electrical system?

Send the vessel details, what was installed or changed, and when it has to enter service. We will set out the test scope and what has to be available on board.