Note
When the Customer Asks for More After Handover
The customer signed the acceptance certificate eight months ago. The 320 kWp solar system is running, the site record is complete, and the annual inspection is already scheduled. Then the call comes: the factory has taken on a new production line, the electricity load has increased, and they want to add another 80 kWp on the roof of Building B.
Good news. The relationship held, the customer is expanding, and the work is already scoped in your head. The risk is treating this post-handover scope addition as a continuation of the original job rather than what it actually is: a new installation that happens to sit beside an existing one.
Why Is a Post-Handover Addition a Separate Job?
The original installation has a signed acceptance certificate with a specific date. Everything it covers falls under a warranty clock that started on that date. The customer, the original equipment suppliers, and your own workmanship obligations all reference that document.
A second installation on the same roof carries its own:
- Warranty start date. The new panels, inverters, and wiring have their own warranty periods starting from their own commissioning date, not the original.
- Acceptance certificate. The customer’s engineering team needs to inspect and sign off on the new work before you can close it. That sign-off should not be tacked onto the original document.
- Commissioning record. String voltages, protection settings, and output measurements for the new system form a separate baseline. Mixing them into the original commissioning record makes it impossible to distinguish what the system could do before and after the expansion.
- As-built drawings. The single-line diagram and cable schedule for the expanded system need to show both what existed and what was added, with the junction point clearly marked.
What Does the Integration Point Require?
When a new system connects to an existing solar installation, the integration point requires documentation that references both:
- Which protection devices isolate the new addition from the original system and from the grid
- How the combined system output was measured after integration (a new commissioning test, not just the addition in isolation)
- Whether the inverter configuration was adjusted to account for the higher combined output
- Whether the original string fusing, cable ratings, or DB space was adequate for the expanded load, or required upgrading as part of the project
That last point matters for both performance and warranty. If adding the new capacity required upgrading a component on the original side, that component now carries the new installation’s warranty date, not the original one. The handover documentation needs to reflect this.
The Informal Request Problem
This problem usually does not arrive as a formal project. It arrives as a conversation.
The factory engineer walks you around Building B while you are on-site for the annual inspection. They point at the roof: “As long as you are here, can you price adding panels on that section? We have budget approved.” The project gets quoted, accepted, and scheduled. Forty additional panels get installed over two days.
When a project starts informally, the documentation often matches: no separate scope document, no acceptance certificate, no commissioning record. The addition ends up as a note in the existing site file, or nowhere.
Six months later:
- An inverter fault appears and it is unclear whether it predates the addition or was caused by the load change.
- The customer asks for an updated system overview and you are working from memory about what was added and when.
- The new panels are inside manufacturer warranty but nobody can confirm the installation date without digging.
How to Handle the Discovery That an Informal Addition Already Happened
Some contractors will read this post because an informal addition already happened and they are now working out what documentation is missing.
The practical steps:
Reconstruct the commissioning record. Use photograph metadata for the date. If the team has notes, those become the record. Acknowledge gaps rather than fill them: “Installed approximately Q4 2025, commissioning measurements unavailable” is more defensible than a fabricated test result.
Update the site record. Correct panel count, inverter configuration, and warranty expiry dates for replaced or added components.
Produce a retrospective acceptance document. A simple document recording what was added, the approximate date, and the customer’s acknowledgment. Getting a signature closes the gap between what the site register shows and what is physically on the roof.
Note what cannot be confirmed. If the integration point was not tested after the addition, say so. An honest record with stated gaps is more useful than one with undocumented assumptions.
What the Site Register Needs to Show
A site that has had a post-handover addition is not the same site it was at original handover. The site register entry needs to reflect the current state of the installation, not only its original state.
The minimum update:
- Original system: capacity, commissioning date, warranty expiry for each major component
- Addition: capacity, installation date, warranty expiry, the name of who supervised the installation
- Integration note: what was changed on the original system (if anything) and the date
This is the record the annual inspector will work from when they return in twelve months. If the site register shows a 320 kWp system and the roof has 400 kWp on it, the first thing the technician will do is call the office and ask what is actually there.
FAQ
Does adding capacity affect the warranty on the original installation?
It depends on whether anything in the original installation was modified to accommodate the addition. If a circuit breaker was upgraded, a cable replaced, or an inverter reconfigured, those changed components carry the new installation’s warranty dates. Everything else on the original system is unaffected. The site record should distinguish clearly between original components and replaced or upgraded ones.
Do we need a full new acceptance process for a small addition?
The scale of the acceptance process should match the scale of the work. A small addition (10 to 20 panels on an existing inverter string) does not need the same walk-through as a new 80 kWp system. But it does need a signed document from someone at the factory acknowledging what was added and the date. That signature is the close of the job. Without it, the addition sits in an open state with no formal endpoint.
How do we present this to the customer without making it feel like unnecessary bureaucracy?
Frame it as protection for both parties. The customer benefits from a clear record of what was added and when, which they will need if they ever claim on the manufacturer’s warranty for the new equipment. The contractor benefits from a clear boundary between the original work and the new work. The additional paperwork is not overhead. It is the documentation that makes the warranty conversation simple rather than complicated when something eventually needs attention.
If you want to see how TRACE 30 handles new job orders alongside an existing site record, the overview is at /program/. To talk through how this applies to your current site list, book a short call at /schedule-a-call/.