Why Does My Home Automation Installation Need So Many Cables?

“Why do you need all these cables?”

Who it’s for: Homeowners building or renovating, and their electricians.

It is a remark that comes up often, usually at the most concrete moment: during a site visit, when the conduits start running through the partitions and false ceilings.

The owner was expecting a smart home. They discover an electrical worksite that looks denser than they imagined. And the question naturally arises: “Why so many cables for a system that is supposed to make my daily life simpler?”

It is a legitimate question, and the answer deserves to be given clearly before the work continues, not after.

A home automation installation does not replace the electrics, it relies on them

The first misconception to correct: home automation is not an alternative to the electrical installation. It is added on top of it, and sometimes reorganises it.

A light point always needs to be powered. A motorised shutter always needs a power source. What home automation changes is not the existence of these electrical circuits, but the way they are controlled and made to communicate with each other. And that communication also needs to travel somewhere.

Why a simple switch can change the whole architecture

In a conventional electrical installation, a switch is wired directly into the circuit of the lamp it controls. The button and the load are one: cutting one cuts the other. This direct physical link imposes a simple limit: a button can only control what it is connected to, nothing more.

In a home automation architecture, this direct link can disappear, and it is this decoupling between the control and the load that changes everything. The button becomes an interface: it sends a piece of information, rather than breaking or making a circuit. The logic that decides what happens to the lamp is then handled elsewhere, often in a dedicated module, sometimes spread across several devices. It is precisely this decoupling that allows a single button to trigger, with one press, the lighting, the shutters, the air conditioning and a complete scene with a time delay, without being physically connected to each of these elements. But this freedom has a price: the information must now travel between the button, the logic that processes it and each device concerned, and that travel requires links that did not exist in a conventional installation.

We saw in our previous article that centralisation, scenes and automation do not refer to the same level of operation: My Apartment Is Sold as “Home Automation”: What Does That Really Mean?. It is exactly this distinction that explains, here, why the wiring changes in nature.

An example: lighting

Lighting is probably the simplest place to observe this evolution.

• Simple control: a switch turns a lamp on or off. The wiring connects the button directly to the load.
• Several controls: two or three switches can control the same light point, as in a corridor. Conventional wiring already becomes more complex for this simple need.
• Dimming: the light no longer just turns on at 100%, its intensity can be adjusted. This requires a module able to handle the dimming, no longer a simple contact.
• Scene: this same light becomes part of an ambience, with other light points, triggered by a single command.
• Automation: the light adjusts on its own, according to the time or the ambient light.
• Integration with presence: it takes into account the actual presence of a person in the room, detected by a sensor, to switch on, switch off or adjust its intensity without any human action.

At each step, the same bulb stays in place. What changes is the number of elements that must communicate to make it work: the button, the presence sensor, the light sensor, the dimming module, the scene logic. Each of these elements needs power, and the way they exchange information depends on the chosen architecture.

When functions multiply, the wiring has to follow

A single light point evolving in this way already represents several additional links. Multiply that by every room in a home, add the shutters, the air conditioning, the heating, the presence and light sensors, the alarm, access control, and sometimes energy management: each function adds its own linking needs, between powering the devices and carrying information between them.

This is when a home can give the impression of being “much more wired” than a conventional one. And that is often true. The question is not whether it is true, but understanding why.

More cables does not necessarily mean more complexity

This is where the perspective needs to change.

An installation with more cables is not necessarily harder to understand, maintain or develop. It is often the opposite: a well-designed architecture clearly separates functions, organises devices and their links around clearly identified points, and documents what connects each element to every other.

An installation with fewer cables, but poorly organised, can on the contrary become much harder to diagnose when something fails, or to extend when a new device is added. The number of cables is not in itself an indicator of quality. It is the way they are organised, grouped and documented that determines whether the installation will remain understandable over time.

The real issue: where do the cables run, and why?

That is the question that really matters, much more than the number of cables itself.

• The architecture: do the cables run back to one or more clearly identified points, or are they scattered according to successive needs?
• The electrical panel: is it sized to hold the modules needed today, and to take more tomorrow without starting over?
• Conduits and cable routes: are they laid so that an extra cable can be added in a few years, or are they full from the start of construction?
• Accessibility: will some connection points remain accessible once the finishes are in place, or will they be permanently buried in the partitions?
• Separation of functions: are power circuits, control circuits and communication networks clearly distinguished, or mixed up as the work progresses?
• Documentation: is there a plan showing where each cable goes and what it corresponds to, or does that information remain only in the installer's memory?

These questions are not about how many metres of cable are laid. They are about the home's ability to remain understandable, repairable and scalable, long after the work is finished.

And this scalability is not limited to the cables themselves. It also depends on the capacity available behind them: spare room in the electrical panel, spare space in the conduits, spare power where relevant, communication and expansion capacity suited to the chosen architecture, or simply a space left accessible for a device that does not exist yet. A scalable installation is not one that has everything from day one. It is one that has been prepared to welcome what is not there yet.

Questions to ask before the walls are closed

The moment the walls are closed is a point of no return. Here are the questions an owner can ask before that stage:

• Does the electrical panel have spare capacity for future modules or circuits?
• Are empty conduits or spare routes planned for later additions?
• Are control, power and communication cables clearly separated?
• Will some connection points remain accessible after the finishes?
• Will a wiring plan be handed over at the end of the work?
• Will this plan allow another professional, several years from now, to understand the installation without having been involved in the project?
• Have the needs of devices not yet installed, such as air conditioning or solar panels, been anticipated?

These questions need to be asked before the walls are closed, not after. Once the partitions are shut, correcting an oversight becomes much more expensive than an adjustment anticipated on paper.

How we approach this kind of project at ExaBuilding

Before talking about wiring, we seek to understand the overall architecture of the home: which functions are planned today, which are likely to be added tomorrow, and how these functions need to communicate with each other.

This thinking comes before the choice of the cables themselves. It determines where to place the reserves, how to organise the panel, which links to separate, and what documentation to hand over at the end of the work. It is this coordination between the electrics and the home automation logic, thought through upstream, that prevents a home from later being blocked by choices made without visibility on its future evolution.

Conclusion

So, why so many cables? Because a home automation installation does not just power devices: it organises the way they communicate, evolve and work together.

Two installations can appear to offer the same functions today while resting on very different architectures: one designed to last and evolve, the other simply assembled as needs arose. This difference is not always visible at handover. It reveals itself a few years later, when you want to add a device, or understand why two apparently similar quotes do not have the same price at all.