Switchgear Testing and Commissioning Checklist
Switchgear is energised only after a sequence of checks, from how it is built to how its protection behaves. This checklist follows the usual order.
1. Before testing
- Approved drawings, protection settings and test procedures issued.
- Factory test records reviewed. See FAT, SAT and IST.
- Safety procedures, permits and isolation arrangements agreed.
2. Visual and mechanical
- Nameplate and ratings match the design; no transit damage.
- Busbar joints, torque marks, earthing connections and labelling checked.
- Breaker racking, shutters and mechanisms operate smoothly.
3. Electrical tests
| Test | What it shows |
|---|---|
| Insulation resistance | Insulation condition between phases and to earth |
| Contact resistance | Quality of joints and breaker contacts |
| Voltage withstand (MV) | Insulation can withstand the required voltage; method per manufacturer |
| CT and VT checks | Ratio, polarity and burden. See CT selection |
| Relay tests | Settings loaded and operation proven. See relay settings |
| Primary injection | The whole protection chain operates from real current |
4. Functional checks
- Breaker open, close and trip operation, including remote and local.
- Interlocks and transfer schemes operated in every sequence.
- Alarms, indications and communications reach the monitoring system.
5. Energisation
- Final permit and a checked sequence.
- Phase rotation and voltage verified at first energisation.
- Load checks and thermal scan under load when available.
This is a general checklist. The manufacturer's procedures, the project specification and the commissioning plan decide the actual tests, values and acceptance criteria.
See also MV switchgear, LV switchgear and the commissioning and handover checklist.
Written by the Vision Matrix Institute editorial team. Worked examples use stated, illustrative assumptions; check them against your project data, the applicable standards and manufacturer datasheets before use.
Frequently Asked Questions
What tests are done on switchgear before energising?
Visual and mechanical inspection, insulation resistance, contact resistance, protection relay tests, interlock and operation checks, and for MV equipment typically a voltage withstand test, all per the manufacturer and specification.
What is primary injection testing?
Passing a real current through the primary circuit to verify the CT ratio, polarity and the operation of the relay and breaker as a complete chain.
Why test interlocks?
Interlocks prevent unsafe or out-of-sequence operation, such as closing two sources in parallel. They must be proven by operating them, not assumed from the design.
Who signs off?
The commissioning engineer or authority with the contractor and client representatives, as defined in the commissioning plan.
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