What is the highest voltage you commission?

132kV. We carry out full bay commissioning at 132kV including protection, control, SCADA and energisation under a formal switching programme.

Do you commission private networks as well as adoptable ones?

Yes. We work on private HV networks for data centres, industrial estates and campuses, and on adoptable networks delivered by independent connection providers.

Do you hold senior authorised person authorisations?

Yes. Our engineers hold SAP authorisation up to 132kV, allowing us to take control of HV systems, issue safety documentation and carry out switching and isolation.

Can you provide the test equipment for site?

Yes. We mobilise with calibrated primary and secondary injection sets, VLF test equipment, transformer test sets, insulation testers and breaker analysers, with traceable calibration certification.

Voltage capability

From 11kV package substations to 132kV bay commissioning

Our engineers work confidently across the full HV range, applying rigorous test and commissioning procedures so that every asset is proven before it is energised.

Voltage range: 11kV – 132kV
SAP authorisation: Up to 132kV
Coverage: UK-wide

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Capability by voltage band

What changes as voltage rises is not just insulation distance — it is protection complexity, documentation burden and the consequence of getting it wrong.

11kV

Package substations & private distribution

The workhorse voltage of UK private networks. We commission package substations, ring main units, switchboards and unit substations — including transformer pre-energisation testing, VLF cable testing, protection and interlock proving, and energisation with load transfer.

RMU and switchboard commissioning
11kV/400V transformer testing and energisation
Overcurrent, earth fault and SEF protection verification
VLF cable testing on new and repaired circuits

33kV

Primary distribution & grid connections

At 33kV the protection becomes less forgiving and the interface with the network operator tighter. Differential, directional and REF schemes are typical, and grading against upstream DNO devices has to be proven rather than assumed.

Transformer and busbar differential schemes
Directional overcurrent and earth fault proving
Primary injection on CT circuits
Settings submissions aligned with DNO protection policy

66kV

Sub-transmission networks

Less common but increasingly relevant on large industrial and renewable schemes. Testing at 66kV brings longer circuits, teleprotection and communications-dependent schemes into scope alongside conventional protection.

Line and transformer differential with pilot / fibre channels
Teleprotection and intertripping verification
Distance protection zone checks
Extended commissioning documentation and witness support

132kV

Bay commissioning & energisation

At 132kV every activity is planned, witnessed and controlled. We commission complete bays — circuit breakers, disconnectors, CTs and VTs, protection and control panels, SCADA — through to energisation under a formal switching programme.

Full bay commissioning including CB timing and analysis
Main 1 / Main 2 protection and duplicated tripping
Busbar protection and check zone verification
SCADA point-to-point and remote control proving

Disciplines we cover on every voltage

Whatever the voltage, the same technical disciplines decide whether an installation is genuinely proven or merely energised.

Primary and secondary injection testing
Protection, control and SCADA integration
Interlocking, trip circuit supervision and DC systems
CT and VT ratio, polarity and burden verification
Circuit breaker timing and mechanism analysis
Earthing and bonding verification
Switching programmes and SAP-controlled energisation
Commissioning documentation and O&M handover packs

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HV commissioning engineers working on switchgear protection panels

Why voltage band changes the commissioning approach

At 11kV, protection is typically non-directional overcurrent and earth fault, and a competent engineer can prove a substation in a day or two. By 33kV, differential and directional schemes appear, CT circuits become critical, and the network operator's grading requirements constrain the settings you are allowed to apply. At 132kV, duplicated protection, teleprotection, busbar schemes and formal switching control mean commissioning is as much a documentation and coordination exercise as a technical one.

That progression is why we scope by voltage band rather than by day rate. The test set is different, the safety controls are different, and the evidence the client and DNO need at handover is different.

Voltage capability — questions we get asked

What is the highest voltage you commission?: 132kV. We carry out full bay commissioning at 132kV including protection, control, SCADA and energisation under a formal switching programme.
Do you commission private networks as well as adoptable ones?: Yes. We work on private HV networks for data centres, industrial estates and campuses, and on adoptable networks delivered by independent connection providers.
Do you hold senior authorised person authorisations?: Yes. Our engineers hold SAP authorisation up to 132kV, allowing us to take control of HV systems, issue safety documentation and carry out switching and isolation.
Can you provide the test equipment for site?: Yes. We mobilise with calibrated primary and secondary injection sets, VLF test equipment, transformer test sets, insulation testers and breaker analysers, with traceable calibration certification.

Need a specialist HV commissioning partner?

Tell us the voltage range, scope and programme dates. A commissioning engineer will come back to you — not a call centre.

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