Testing & Commissioning, simply put

Testing & Commissioning (T&C) is the structured process of bringing an electrical system from "installed and de-energised" to "operational and proven safe." Every cable, switch, protection relay, transformer and earth has to be measured, witnessed and recorded. A handover certificate that isn't backed by a complete T&C package is paper, not proof.

A PE Electrical with hands-on commissioning experience adds three things contractors typically don't: independence (no commercial pressure to skip steps), statutory authority to sign off where regulations require it, and technical depth across both AC distribution and DC traction systems.

Two domains, one engineer. Few Singapore engineers have current experience across AC power (industrial, commercial, residential) and DC traction power (750/1200 VDC for rail). Er. James has both — built up over LTA's rail expansion years and Changi Airport's utility lead role.

Scope of works covered

AC power systems

HT switchgear T&C — 22 kV and 66 kV RMUs, vacuum circuit breakers, SF6 switchgear.
Transformer T&C — ratio, polarity, winding resistance, insulation resistance, oil/gas analysis.
LV switchboards — main switchboards, sub-main, sub-distribution boards, ASTS / ATS transfer.
Protection relay testing — overcurrent, earth fault, differential, distance, directional. Secondary injection, primary injection, end-to-end where required.
Earthing and bonding — fall-of-potential, soil resistivity, equipotential bonding verification.
Cable T&C — insulation resistance (Megger), HV pressure test, VLF test, partial discharge where specified.
Power-up sequence — pre-energisation checklists, first-energisation, load test, full system handover.

DC traction power systems

750/1200 VDC rectifier substation T&C.
DC switchgear protection — high-speed circuit breakers, di/dt, dI protection.
Third rail / overhead catenary energisation procedures.
Stray current monitoring system commissioning.
Negative return system integrity testing.

The process

Commissioning plan review. Before any energisation, we audit the contractor's commissioning method statement, ITPs (Inspection & Test Plans) and test record templates. Gaps are flagged before site work begins.
Pre-energisation walk-down. Visual inspection of the installation — labelling, segregation, IP integrity, earthing continuity, switching device positions.
Static tests. Insulation resistance, continuity, polarity, ratio, secondary injection of relays — all done with the equipment de-energised and isolated.
First energisation. Switching sequence executed under a Permit-to-Work. Live measurements: voltage, phase rotation, no-load current, neutral imbalance.
Functional tests. Protection trip tests, interlock verification, ATS transfer simulation, busbar transfer, generator black-start where applicable.
Load tests. Phased load-up, thermal scans, harmonic measurement, power quality logging.
Handover. Final witness, defect close-out and signing of the Hand-Over Certificate and Test & Commissioning report.

Documents we produce or witness

T&C Method Statement (TCMS) endorsement.
Test result records — insulation, continuity, ratio, polarity, relay settings.
Protection relay setting sheets — verified against the protection co-ordination study.
Permit-to-Work register (issued by the LEW).
Hand-Over Certificate to the client, MCST or building owner.
As-built single-line diagram updates.
Operations and Maintenance manual review.

Standards we test against

SS 638 — Code of Practice for Electrical Installations.
IEC 60364 — Low voltage electrical installations.
IEC 61936 — Power installations exceeding 1 kV AC.
IEC 62271 — High-voltage switchgear and controlgear.
IEEE C57 — Transformer testing series.
IEC 60255 — Measuring relays and protection equipment.
SP PowerGrid Service Connection Document — for SP-side intake commissioning.

Frequently asked questions

Do you carry your own test equipment?

For most T&C engagements, the contractor supplies the test equipment (insulation tester, secondary injection set, primary injection, transformer test set). We bring the engineering, the independence and the sign-off authority. For specialist tests we can arrange or recommend appropriately calibrated instruments.

Can you commission a project we didn't design?

Yes — many of our engagements are pure commissioning. We catch up on the design intent quickly through document review, and our role is to verify the installation against the design, not re-author it.

How does PE-witnessed T&C differ from contractor T&C?

Contractor T&C is self-certification — useful and necessary, but the contractor signing off on its own work is not independent. A PE-witnessed sign-off carries the weight of a Singapore-registered Professional Engineer who is staking their licence on the result.

What if defects come up during T&C?

Defects are logged in a snag list, given severity, and rectification is verified before the handover certificate is signed. We do not sign off on systems with unresolved safety-critical defects, no matter the schedule pressure.

Testing &
Commissioning