Panel Commissioning Checklist: Step-by-Step Verification on Site
Panel commissioning: Commissioning is the final verification that brings factory testing together with real site conditions.
ContentsPanel commissioning is the stage where the routine verification carried out in the works is re-tested against site conditions: installation, cabling and supply. An assembly that left the factory flawless can still cause trouble on site because of a connection loosened in transport or a wrongly landed neutral.
The five stages of commissioning
The order matters: each step assumes the previous one has been verified. If checks that belong before energisation are skipped, the results of later tests cannot be trusted.
1. De-energised visual inspection
The first task once the assembly arrives is to look for transport damage and loosened connections. Busbar bolts are checked with a torque wrench and marked; terminal tightness is reviewed in full rather than by sampling. This stage also confirms that labels match the diagram, that compartment covers are in place, and that cable entries are sealed correctly. For label content, see the panel technical file.
2. Insulation resistance and continuity
Insulation resistance is measured with electronic devices disconnected; otherwise both the reading and the equipment suffer. The measurement is repeated phase to phase, phase to neutral and between all conductors and earth. Continuity of the protective conductor and the bonding of every metal part to the main earth bar are then verified with a low-resistance measurement.
| Test | Purpose | Typical acceptance |
|---|---|---|
| Torque check | Keep contact resistance low | Value stated by the manufacturer |
| Insulation resistance | Integrity of insulation | Commonly above 1 MΩ |
| Protective conductor continuity | Touch safety | Very low resistance |
| Phase sequence | Motor direction of rotation | Sequence as per diagram |
| Functional test | Interlocks and signals | Logic as per diagram |
3. Functional and interlock testing
With control voltage applied, the logic of each circuit is exercised separately: open and close commands, auxiliary contact feedback, interlocking arrangements, the emergency stop chain and alarm outputs. On transfer panels the mechanical interlock must be shown to work with the control supply removed; the interlocking logic is covered in automatic transfer switch. Protection settings are entered at this stage and recorded individually.
4. Energisation and verification under load
Power is applied in steps: the incomer first, then distribution levels, and finally outgoing circuits. Phase sequence and voltages are measured and imbalance is checked. Once load has been applied for at least an hour, a thermographic survey provides a valuable baseline. How that measurement is interpreted is covered in thermographic inspection.
What the commissioning file should contain
Tests are only worth as much as the records they leave behind:
- As-built single-line diagram and terminal schedule
- Calibration details of the instruments used
- Insulation resistance and continuity readings
- Table of protection settings
- Functional test record with signatures
- The first thermographic report and the load at the time
- Maintenance instructions handed to the user
Key takeaways: panel commissioning
- The five stages of commissioning — The order matters: each step assumes the previous one has been verified.
- 1. De-energised visual inspection — The first task once the assembly arrives is to look for transport damage and loosened connections.
- 2. Insulation resistance and continuity — Insulation resistance is measured with electronic devices disconnected; otherwise both the reading and the equipment suffer.
- 3. Functional and interlock testing — With control voltage applied, the logic of each circuit is exercised separately: open and close commands, auxiliary contact feedback, interlocking arrangements, the emergency stop…
- Standard source — IEC publication catalogue: iec.ch.
Frequently asked questions
Why test on site when factory tests exist?
Factory testing verifies the assembly itself. Site testing verifies transport, installation, cabling and supply conditions. Neither replaces the other.
What voltage is applied for insulation testing?
500 V DC is common practice for low-voltage assemblies. Where sensitive electronics are present, the manufacturer’s limit must be respected and the circuit isolated if necessary.
When should the first maintenance take place?
A common approach is to repeat torque checks and thermography at the end of the first year, since connections can settle and loosen during the early months.
Related articles
- Switchboard Technical File, Rating Label and CE Conformity
- Busbar Current Carrying Capacity and Derating Calculation
- What is the IEC 61439 Standard? Type Testing and Conformity in Low Voltage Switchgear.
- All technical articles
Devpan supplies a commissioning checklist and test records together with the technical file for every assembly it delivers. Share your site programme and we will plan the commissioning process with you.
