Solar panel installation: what happens from site visit to switch-on

Solar installation isn’t a single visit and done. It’s a process with a paperwork stage and a physical stage, and knowing what happens at each point makes it easier to tell whether an installer is moving things along properly or leaving you in the dark. If you’re still comparing providers, our directory of solar panel installers is a good place to start once you know roughly what to expect.

The stages, in order

Stage	What happens	Rough timing
Site visit and assessment	Roof condition, orientation, shading, and existing wiring are checked; usage reviewed	Single visit
Quote and system design	Panel count, wattage, inverter capacity, and mounting plan finalised	A few days to a week
Paperwork submission	Application to TNB and SEDA under the Net Energy Metering scheme	Several weeks, varies by provider
Physical installation	Panels mounted, wired to inverter, connected and tested	One to three days
Inspection and commissioning	System tested, inspected, and formally approved for grid connection	Days to a few weeks after installation
Switch-on and handover	System goes live, monitoring set up, warranty documents provided	Same day as final approval

The site visit is where the real quote starts

A phone estimate for solar is close to meaningless, because so much depends on your roof. The site visit is where an installer checks your roof’s structural condition, which direction it faces, whether nearby trees or buildings cause shading during parts of the day, and how your existing consumer unit is set up. They should also ask about your actual electricity usage rather than just going off your roof’s maximum capacity, since a system sized to your usage pays back faster than one sized purely to fill available roof space.

If an installer skips this step and gives you a firm quote over the phone, treat that as a sign to look elsewhere, not a convenience.

Paperwork runs in parallel with, not after, physical work

One of the more common points of confusion is assuming installation happens first and paperwork follows. In practice, TNB and SEDA submission under the Net Energy Metering scheme usually needs to happen before or alongside the physical install, since the system isn’t legally allowed to connect to the grid until it clears. A properly registered installer manages this as part of the job. If a provider is vague about who’s handling the TNB and SEDA submission, or seems unfamiliar with the process, that’s a real red flag, not a minor gap.

What the installation days actually look like

Once materials are on site, mounting the panels, running the wiring to the inverter, and connecting everything typically takes one to three days for a residential system, depending on size and roof complexity. During this stage, a good installer keeps cable runs tidy, uses corrosion-resistant mounting brackets, and places the inverter somewhere ventilated and out of direct sun rather than wherever’s most convenient. Ask to see this before they leave, since a rushed installation often shows up as messy cabling or a poorly placed inverter, even if the panels themselves look fine from the ground.

Testing before switch-on

Before the system goes live, it should be tested for proper earthing, correct wiring, and safe operation. This isn’t a step to skip regardless of how eager everyone is to see it switched on. A competent installer walks you through what was tested and what the results mean, rather than just flipping a switch and calling it done.

After switch-on

Once commissioned, most systems come with a monitoring app so you can track output and confirm the system is performing as expected. It’s worth asking your installer to walk you through this at handover, along with what warranty covers the panels versus the inverter, since these commonly carry different warranty lengths. Panels themselves need little upkeep beyond occasional cleaning if dust or bird activity builds up, but it’s worth having the system checked every year or two to confirm connections are tight and the inverter is still performing as it should.

For more on how we score solar installers on licensing and workmanship, see our methodology, and visit the homepage to compare providers across all electrical categories.