Note
Taking On a Site You Didn't Install: Pre-Maintenance Survey
When a factory contacts you about maintaining a system you did not install, the instinct is to quote from the specification: system size, visit frequency, response time. That approach works when you can assume the installation is sound. A pre-maintenance survey changes the process: it is the site visit you conduct before signing an agreement, not after, to understand what the real condition of the system is before you commit to it.
What Are You Actually Agreeing to Maintain?
The answer is rarely obvious when you arrive at a site someone else installed.
C&I solar and industrial LED lighting installations leave documentation that ranges from complete and well-organized to nearly nonexistent. The original contractor may be unavailable, may have closed, or may have moved on without producing final records. The factory’s engineering department may have the commissioning report filed somewhere accessible, or may not be able to find it at all.
Before the site visit, request the following documents:
- As-built drawings. Not the design drawings submitted for the permit, but the drawings updated to show what was physically installed.
- Commissioning report. The test results from the date the system was signed off: insulation resistance values, earth fault loop impedance, protection relay settings, or for solar, the initial string current and voltage measurements by array.
- Equipment warranty documents. Serial numbers, purchase dates, and warranty expiry dates for inverters, protection relays, switchgear, luminaires, and other major components.
- Previous service and fault records. Anything the factory has kept since commissioning, including informal maintenance logs or fault call notes.
You will often receive less than you asked for. Note what is missing. A site with no commissioning report is one where you cannot verify the baseline condition, and that uncertainty belongs in your scope terms, not absorbed silently into the rate.
What Does the Physical Walk-Through Tell You?
Documents tell you what should be there. The site visit tells you what is.
For industrial LED lighting, check:
- Driver condition in high-heat zones: near furnaces, process machinery, and poorly ventilated ceiling areas where ambient temperatures remain elevated for long periods.
- Evidence of lamp or driver replacements since installation, and whether the replacement parts match the original specification.
- Earthing continuity on metal fittings and cable trunking.
- Cable condition in areas with mechanical traffic: forklift routes, overhead handling equipment, and areas with sustained vibration from production machinery.
For C&I rooftop solar:
- DC combiner box condition: signs of discoloration, corrosion, or loose terminations at string connections.
- Inverter display status and any fault codes showing at the time of the visit.
- AC protection equipment: is the switchgear the original specification, or has it been modified since commissioning?
- Mounting structure: loose fixings, corrosion at mounting points, or physical damage to panels.
The condition you find tells you whether the original installation was completed to a reasonable standard and what the first year of maintenance will actually involve.
What Red Flags Should Change Your Terms?
Some findings warrant scope adjustment before you sign. Others warrant pausing before you proceed.
Findings that typically require scope adjustment:
A partial earthing installation is a major corrective job, not a routine check. Name it separately with its own schedule rather than absorbing it into the maintenance rate.
Equipment with expired warranties that the factory expects you to cover: a protection relay whose two-year warranty expired in month fourteen becomes your parts-and-labor cost if the scope includes repairs. Review every warranty expiry date before you sign.
No record of the statutory annual electrical inspection. Include a clause requiring the factory to bring inspections current before the agreement begins, or accept the compliance gap consciously and price it into your rate.
How Do You Create Your Own Baseline Record?
When you accept the maintenance of a site you did not install, the first visit’s output is a baseline record: a documented snapshot of the system’s condition at the date you took it over.
The baseline record should contain:
- Equipment inventory with make, model, serial number, and location for each major component.
- Visual inspection findings with photographs, organized by section of the installation.
- Each defect observed that falls outside this visit’s scope to resolve, with the remediation action required and the party responsible for it.
- Warranty status for each major component at the date of takeover.
- Outstanding items from the most recent statutory inspection, if any exist.
This record establishes what the system looked like the day your involvement started. Without it, any defect found in the first year is potentially yours to explain, even if it predates your involvement by several years. With a co-signed baseline, you and the factory have agreed on the starting condition.
A worked example: a contractor taking over a 250 kW rooftop solar installation in Rayong finds three string connections in a DC combiner box showing discoloration consistent with arcing, and no commissioning report. The baseline record photographs each connection and names them as pre-existing defects requiring remediation within the first 60 days, priced separately from the maintenance scope. When the remediation is completed and signed off, that record enters the site’s service history and the ongoing maintenance starts from a clean baseline.
How Does a Baseline Feed Your Ongoing Records?
Each subsequent visit, fault call, and part replacement adds to the baseline. By the time year one’s agreement comes up for renewal, you have a real service record for a site you inherited with no documentation. The warranty clocks flag when components leave coverage. The inspection date carries forward. A documented baseline lets you manage an inherited site the same way you manage the ones you installed yourself.
FAQ
What if the factory has no as-built drawings and cannot find them?
Proceed based on the physical installation. Create a simplified inventory document recording what is there, where it is, and its observed condition. State in the maintenance agreement that the scope is based on the as-found condition at the survey date and that discrepancies identified later will be priced separately. Not a perfect starting point, but an honest one.
Should pre-existing defects be in the same agreement as ongoing maintenance?
Keep them separate. Write a one-time remediation scope with its own schedule, and a standard maintenance scope for ongoing work once the system is at an agreed baseline. Combining them makes the recurring maintenance cost impossible to read and creates a dispute when the pre-existing work takes longer than expected.
Should the factory representative sign the baseline record?
Yes. A co-signed baseline establishes the system’s condition at takeover as agreed by both parties. Ask the most senior engineering contact present to sign. That signature is the record that matters if the installation’s condition becomes a dispute later.
If you are adding inherited sites to a maintenance portfolio alongside the ones your team installed, Field Operation System includes a site register that builds from closed jobs, including baseline surveys. The warranty clocks, inspection calendar, and maintenance history work the same way whether the site was commissioned by your crew or recorded at takeover. See how the program works at /program/.