What is the biggest benefit of pre-installation for PV on a new build home?

That you avoid future excavations, external channels and aesthetic interventions, with minimal additional costs at the construction stage.

Why do we ask for long and separate pipes from the roof to the inverter?

To pass DC cables, grounding and communication without difficulty, but also to reduce the risk of interference and blocking of passages.

Pre-installation of Photovoltaics in New Construction: How to correctly run the pipes from the roof to the basement

If you are in the phase of building a new home or doing a radical renovation ("in beta"), you have a golden opportunity in your hands that should not be missed. Pre-installation for PV is probably the most "value for money" move you can make.

The cost for the electrician to run a few empty pipes through the walls while the house is being built is literally zero. But if you decide to put photovoltaics on a finished house 5 years later, you will be faced with a dilemma: Either you will have to dig up freshly painted walls, or you will fill the facades of your house with ugly, exterior plastic channels that will descend from the roof to the ground floor.

As engineers, we've put together a handy guide on exactly what to ask your electrician at the pre-installation stage to make your home 100% "Solar Ready".

1. The Routing Problem (The Route)

A PV system requires the connection of three different "hubs" in your home:

The Panels (Located on the roof or roof).
The Inverter & Battery (Usually located in a basement, warehouse or garage).
The Central Electrical Panel (Usually located on the ground floor or at the entrance).

The challenge is to create "avenues" (empty pipes) that connect these three points, allowing the cables to pass comfortably.

Illustration for 1. The Routing Problem (The Route)

2. The Golden Rule of Pipes (No "straws")

The biggest mistake contractors make is that they leave a simple, thin electrician's pipe (eg Φ16 or Φ20) thinking it will suffice. PV cables (DC cables, communication cables, thick grounding) are many and rigid.

The Right Size: Have the electrician run two (2) separate, straight pipes at least Φ40 or Φ50 in diameter (Heliflex type or heavy duty thick spiral) from the roof to the Inverter area.
Why two? One pipe will house the power cables (carrying the current) and the second the ground wire and the data/internet cable. If you put them all in one pipe, the current can interfere with the communication of the Inverter with the internet.
The Rule of Straightness: These pipes must descend as vertically as possible. Avoid sharp 90 degree corners. If there are corners, when the time comes to pass the "steel" with the thick cables, it will stick.

3. The Choice of Space for the Inverter & Battery

The Inverter is not a decorative element that enters the living room. It is a power machine that has specific requirements:

Weight: Lithium batteries are extremely heavy (a 10kWh battery can weigh over 100kg). The wall you choose must be load-bearing (concrete) or built with solid bricks. It is prohibited to hang large systems on simple plasterboard.
Temperature & Ventilation: Inverters get hot and heat is a batteries worst enemy. Choose a cool, ventilated area (eg basement, northern garage). Do not place them in narrow, closed cupboards under stairs without ventilation.
Noise: Hybrid Inverters have fans and internal relays that make a characteristic "click". Do not install them on walls adjoining bedrooms.

Illustration for 3. The Choice of Space for the Inverter & Battery

4. The Connection to the Central Board

After determining where the Inverter will go in the basement, you must take care of its connection to the central electrical panel of the house.

The Supply Pipe (AC)

Pass a pipe (at least Φ32) that connects the Inverter space with the central panel. From there will pass the thick supply cable (eg 3x6mm² or 5x6mm² for three-phase).

The Data Pipeline

You definitely need a second, thinner tube for the Communication Cable (UTP/CAT6). This cable will connect the Inverter to the "Smart Meter" we mentioned in the previous chapter, which will be placed inside the central panel.

5. Roof / Roof Preparation

Finally, where the pipes end on the roof, make sure:

The pipes "go out" into a watertight well or have a turned "neck" (like a cane) downwards, so that rainwater does not enter the house.
Provision should be made for central grounding. The PV base (the aluminum frame) must be connected to your home's foundation ground for ultimate lightning protection.

Summarizing

Pre-installation for PV in a newly built home is mainly a matter of proper piping design and space planning. Ask your mechanic and electrician to work together to leave you large diameter "empty roads". This move will cost you less than €100 in plastic pipes today, but will save you thousands of euros in digging and unsightly interventions tomorrow.

Next Step: All this is great if you have your own rooftop or roof. But what if you live in an apartment building? Is there hope for you? We answer the most "hot" question of the time: Balcony Photovoltaics (Plug & Play): Are they legal? How they are connected to the socket and what you should pay attention to.

Electrical Panel Requirements for Rooftop PV: What Your Electrician Should Add Hybrid Inverters: What they are and why they are the heart of every modern system Interfacing Batteries to the House Panel: AC Coupling vs. DC Coupling – Simplified guide Balcony Photovoltaics (Plug & Play): Are they legal? How they are connected to the socket and what you should pay attention to

Electrical Supply, Power & Autonomy

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