Solar Panel Installation — the Electrical Side — in Odemira and the Costa Vicentina

What the Electrical Part Actually Covers

A domestic solar system has three parts, and only one of them is "panels". There are the modules on the roof, the inverter that converts the DC the panels produce into usable AC, and the connection into the house consumer unit — which is where the system stops being equipment and becomes part of the electrical installation.

That third part is ours: dedicated circuit from inverter to consumer unit, protection on both the DC and AC sides, isolation, earthing of the array and its frame, and integration with the protection already in place. It is also the part most often done badly when a system is sold as a sealed package and fitted in a hurry.

Earthing the modules and the mounting frame is not a formality. A roof array is the highest point of the house, and without proper bonding and a surge protective device it becomes the preferred entry point for a surge. In this area, where much of the grid is overhead and late-summer storms are frequent, that matters considerably more than it would in a city.

Sizing: the Calculation Almost Nobody Does

What decides your saving is not installed capacity — it is how much of what you generate you can use at the moment you generate it. That is your self-consumption rate, and it determines the real return far more than the number of panels.

In a house that is empty during the day, a large system produces when nobody is consuming, and the exported surplus is worth much less than the energy you avoid buying. In that situation more panels do not improve the numbers. What improves them is shifting consumption into daylight hours — washing machine, water heater, pool pump, car charging.

This is why sizing a system by available roof area is the most expensive mistake in the sector. Correct sizing comes from your actual consumption pattern, which you read off your bills and your habits, not off the roof.

Batteries: When They Make Sense and When They Do Not

A battery stores the day's surplus for use at night. It makes sense when your self-consumption rate is low because of your hours and you cannot shift consumption, or when there are frequent grid outages and you want autonomy — a more common situation in the outlying parts of this municipality than in town.

It makes less sense when consumption is already daytime-heavy, because the battery ends up doing a job the house was already doing for free. In that case the money returns more if it is spent elsewhere in the installation.

What you need to know beforehand is that a battery changes the protection and the operating mode of the whole system, particularly if it is to run in island mode when the grid fails. It is not an accessory you bolt on without touching the rest.

Our Scope, Stated Plainly

We carry out the interior electrical work and its certification: inverter connection, consumer unit, protection, earthing and the documentation the installation requires. We work on systems we supply and on systems bought elsewhere, including kits bought online.

What is not in our scope is the physical grid connection in cases that require a medium-voltage responsible engineer. For grid-export installations that fall into that category we coordinate with an external engineer, and we say so before there is any commitment.

We also do the part that tends to be forgotten: preparing the house for solar before it exists. If you are renovating, leaving conduit and a cable route from roof to consumer unit costs very little now and saves a full job in two years' time.

I bought the panels elsewhere. Will you do just the electrical work?

Yes, and it is a frequent request. We ask to see the datasheets for the inverter and the modules first, so we can confirm protection ratings and cable sizes. We do not connect equipment we cannot verify technically.

How many panels do I need?

That comes from your actual consumption and your hours, not from the roof area. With a year of bills and a conversation about habits it can be sized quite accurately. Installing more than you can consume is the most common way to spend money that does not come back.

What if the roof is old tile, or has asbestos cement?

The mounting system changes, and there are cases where it is not advisable. On an old fibre-cement roof you do not drill or fix anything without resolving that first, and that is not an electrical question. We say so at the site visit rather than leaving it for installation day.

Can you prepare the house now and install solar later?

Yes, and it is one of the most worthwhile things to do during a renovation. Leaving conduit and a cable route from roof to consumer unit costs very little at that moment and avoids a full intervention when you decide to go ahead.

Do you work on systems for holiday lets?

Yes. There the interesting question is usually consumption pattern rather than capacity: guest occupancy is concentrated in summer, which is also when production peaks, so self-consumption tends to be unusually high.