The installation line on a solar quote is a scope statement, not a price. It is the only part of the document that describes your building rather than your equipment — the roof, the height, the cable route, the board at the end of the run — and until two quotes describe the same physical works, the totals at the bottom are measuring two different jobs. Read that line first, and treat everything above it as a list of hardware that any competent supplier can match.
I want you standing next to me in the driveway rather than reading this at a desk, because the line only makes sense when you can see what it is pricing. Two-storey face-brick house, concrete tiles, a north roof that looks flat and friendly from the road, and a distribution board tucked behind a passage cupboard door that opens ninety degrees and stops.
On the kitchen table inside are two quotes. The numbers here are illustrative, not a market survey: one puts installation and commissioning at R14 800, the other at R21 500. Panels, inverter and battery are close enough to the same category that the difference sits almost entirely in the installation line. Read only the totals and I bin the more expensive one.
So we walk it. Down the side of the house, past the geyser, along the boundary wall, in through the passage to the board. The installer taps the quote against his thigh and counts the bends out loud. I look at where the wall meets the paving and ask whether the cable goes over the top or gets chased in. I stand under the roof sheet and look at the purlins. Fifteen minutes of walking tells me more than two pages of specification.
That is when R6 700 stops being a price and becomes a scope. The higher quote assumed scaffolding at the roof edge, a second body on site for the height, a longer cable run than the other one allowed for, and a new distribution board. The lower quote assumed none of it. Same house, same sun, two different buildings described in the two documents.
Counting the bends, not the panels
I don't size cable. That's the electrician's job and the certificate depends on it. What I do is ask a simpler question: what route did you size it for?
The cable run between the array, the inverter and the main board is the quiet driver of the installation line. Labour and materials both scale with it. An inverter hung in a hot garage adds a run back to the house and a ventilation problem. An inverter on the north wall of a bedroom passage adds trunking and a low hum nobody warned you about. That position is usually chosen during a phone call, and it decides more of the installation line than the brand of the inverter does.
Most quotes carry an assumption somewhere — something like "up to 15 metres of cable included" — or they carry nothing at all. If the real route is 35 metres with a wall in the middle, one of two things happens: the installer eats the difference and starts looking for corners to cut, or you get a variation order a week in. I ask for the assumed length and the rate per additional metre in writing, before I sign anything. If the answer is vague, that vagueness is the product.
Height, anchors and a roof nobody walked on
Scaffolding, edge protection, roof anchors and harnesses are not accessories. They are the priced answer to two questions: how high, and how pitchy? A single-storey pitched roof might need no more than a ladder and a harness. A double storey with a steep pitch is a different job on a different day rate, and the panels still have to get up there — sometimes by hand up a narrow side passage, which is labour nobody quotes for until they're standing in it.
Then the roof itself. Concrete tile, clay tile, fibre cement, IBR sheeting, slate, flat concrete with torch-on — each changes the mounting method and whether the surface is walkable at all. Rusted sheets and perished waterproofing change it again. Asbestos roofing, still common on older South African houses, isn't a mounting decision; it's a handling and disposal decision, and a quote written as if the roof were cement tile is wrong on method, not just on price.
Which is why I treat any quote issued without a site visit as provisional, and I want it to say so on the paper. If the installation line was priced off a satellite photo, then the roof type, the roof condition and the cable route are all assumptions, and the polite version of an assumption is a proviso in writing.
Where the cable ends: the board, the earth and the old wiring
The inverter circuit has to land somewhere. In a newer house there may be spare ways in the distribution board. In an older one there may be none, or no surge protection, or an earth continuity problem that predates the solar by twenty years. Replacing or upgrading that board is a real line item, and in an old house it can rival the inverter itself. Sometimes it is priced separately. Often it isn't mentioned at all.
Earthing and bonding sit in the same place. They are checks first — the main earth conductor, the earth electrode, the bonding on the geyser and the water pipes — and work second, if the check fails. A quote that says "earthing included" tells me nothing. A quote that says the earthing and bonding will be tested and remedied as required tells me the person has opened a board in an old house before.
There's a limitation worth stating plainly: the electrician signs the Certificate of Compliance for the work done, but he cannot certify a board with pre-existing faults. So remedial work is the cost nobody predicts. The only thing you can do about it is ask upfront how it will be handled and who carries it.
Trunking, making good, and the words that must be in writing
Cable on an outside wall needs protection from the sun. Cable inside a house either goes into the plaster or into surface trunking. Then someone has to fill the chase, plaster it, paint it, and seal the hole through the wall so that a Cape winter doesn't leave you with a damp patch on the ceiling. Solar installers rarely have a painter on staff.
So I look for three things in the installation line: trunking (or conduit), making good, and the word excluded. If none of the three appear, I assume the answer is "excluded" and I get it confirmed by email. It costs nothing to ask, and it's the difference between a tidy job and a wall you'll be staring at for the next fifteen years.
Reading two quotes as one job
Here is the habit that changed how I read quotes. Fold the equipment list back. Write the installation assumptions side by side and mark each one Included, Excluded, or Silent. Silent is the dangerous one, because silent items are where the arguments live.
The list I send, in identical wording to both installers:
- Cable route assumed, and the rate per metre beyond it
- Inverter position assumed, and who chose it
- Height and access provisions — scaffolding, anchors, edge protection, extra labour
- Distribution board work, and the scope of any remedial work
- Earthing and bonding — tested and remedied, or not touched
- Trunking, making good, and sealing of wall penetrations
- Certificate of Compliance, and the municipal SSEG application with its NRS 097-2-1 requirements
That's seven, and the paperwork is the seventh. Someone has to compile the SSEG application, line it up with the municipality's approved inverter list, and be available for any inspection. That is hours of work sitting inside the installation line — or hours you'll be doing yourself in three months.
Two more things I read now that I didn't used to. Where the money sits, because a low installation line with high hardware prices isn't cheaper; it's the same total with the labour loaded into the panels, which changes what happens when something goes wrong later. And the payment schedule, because milestones tell you what the installer has actually planned for. If nothing in that schedule covers scaffolding or a second body on site, he isn't planning to hire either.
When the line stays silent, I don't argue on the phone. I send one email with the same seven questions to both installers and wait. Whoever answers in writing, in scope, gets taken seriously. Whoever says "ja, we'll make a plan" is telling me exactly what the plan will look like once they're on my roof.
The cheapest installation line I've ever seen wasn't cheap. It was incomplete. And the number worth comparing was never the one on that line — it was the scope standing behind it.
