Will solar inverter repairs require electrical certification?
Not every solar inverter repair requires electrical certification. If the work alters the fixed wiring, protection or inverter installation, we’ll confirm what certification is required and provide the relevant paperwork; a like-for-like repair may only need a service record.
The paperwork depends on whether we are repairing the existing electrical installation or changing it. A service record may be enough for an internal inverter repair. Work that changes the inverter, cabling, isolation or protective devices needs documented inspection and testing, with the appropriate certificate for the work completed.
A diagnostic visit does not usually create a certification requirement by itself. We can inspect the fault codes, check the DC and AC sides, test the isolators and confirm whether the problem sits in the inverter or elsewhere in the system. If the inverter remains connected as it was and no electrical alterations are made, we record the findings and the repair rather than issuing a new installation certificate.
Internal component work is different from work on the fixed wiring. A manufacturer-approved repair, firmware update or replacement of an internal part may leave the installation unchanged. The inverter still needs to be safe to return to service, so we check its operation and record what was done. Some manufacturers require their own authorised repair process, particularly where the inverter remains under warranty.
Replacing the complete inverter normally involves more than removing one box and fitting another. We check the replacement unit’s electrical characteristics, connector arrangement, earthing, isolation and protection. We then test the DC and AC circuits before commissioning it. The certificate may be a Minor Works Certificate or an Electrical Installation Certificate, depending on how much of the installation has changed. We choose the correct document rather than issuing a generic certificate for every job.
Some changes need additional records or approval beyond the electrical certificate:
- Different inverter output: if the replacement can export more power, the distribution network operator may need to be notified or approve the connection under the relevant G98 or G99 process.
- Altered cabling or protection: changes to cable sizes, isolators, consumer-unit connections, earthing, RCDs or surge protection need testing and recording.
- Changes to the wider system: adding battery storage, changing the export arrangement or reconfiguring the PV array can create further design, commissioning and notification requirements.
- Export records: if the installation is registered for the Smart Export Guarantee, changes to the system may need to be reflected in the documentation held by the supplier or scheme administrator. MCS certification supports the documentation needed for an eligible installation.
An inverter replacement certificate does not replace the original solar paperwork. We keep the existing design information, commissioning figures and previous certificates in view, then record the new equipment and test results alongside them. That gives you a clearer record for future fault finding, warranty discussions, an export tariff application or a property sale.
The tests normally include continuity and polarity checks, insulation resistance where appropriate, earthing arrangements, protective-device operation and inverter commissioning. We also confirm that the inverter starts correctly, shuts down when the relevant isolator operates and displays the expected generation information. The exact tests depend on the equipment and the alteration.
If the original documents are missing, that does not automatically prevent a repair. We can assess the installation as it stands, identify any safety issues and explain which records can be recreated and which cannot. An inspection report may be more appropriate than treating an old system as a new installation, particularly where the array, cabling and consumer-unit arrangement have not been fully documented.
After the work, ask for the service report, test results and any certificate or network notification that applies. We explain what was changed and give you copies of the paperwork. As NICEIC- and ECA-registered electrical contractors, we can deal with the electrical testing and the associated certification when the inverter repair involves fixed wiring or protective equipment.
The certificate’s scope matters. It records the electrical work we carried out, not a blanket approval of every panel, cable and component installed years ago.
If we alter only the inverter connection, the paperwork should identify that circuit and the tests completed. If we find wider defects, we explain them separately rather than making an older array appear newly certified. You’re left with an accurate record of what we inspected, changed and commissioned.
