Why Do You Need Such a Large Electrical Panel?

Who it’s for: Building owners preparing a construction or renovation project.

"Why is the electrical panel so big?"

This is a question we hear regularly when a project moves from a conventional electrical installation to one incorporating home automation, BMS or various technical systems.

And it's a perfectly legitimate question.

For a long time, the electrical panel was seen as equipment to be minimised as much as possible: a few rows, a few breakers, everything fitting into a discreet space.

But when designing an electrical installation for a modern building, the size of the panel becomes a consequence of the architecture, not simply a matter of space.

A Small Panel Is Not Necessarily a Good Panel

Two installations can power the same equipment and yet require very different panels.

Why?

Because the number of modules depends on how the circuits are organised, protected, distributed and prepared for future changes.

Let's take a simple example.

For a small residential installation, a relatively compact panel may be enough. Conversely, a heavily equipped villa or a commercial building incorporating numerous circuits, automation equipment, HVAC, communication interfaces and spare capacity for future changes can quickly require several extra rows.

There is obviously no universal size: the volume depends on the project, the circuits, the equipment and the applicable regulations.

But this helps us understand one thing:

It's not just home automation that makes the panel bigger. It's the entire technical architecture.

Automation Doesn't Just Fill the Panel

This is often the client's first surprise.

An installation incorporating home automation or BMS is not simply about adding a few smart devices.

Depending on the project, the panel may include:

• protection devices for the various circuits;
• power supplies;
• actuators;
• interfaces and gateways;
• communication equipment;
• contactors or relays;
• HVAC-related equipment;
• DALI, Modbus, BACnet or other system interfaces;
• and spare capacity for future changes.

But above all, this equipment must be organised and accessible.

A properly designed panel is not a box into which you try to cram the maximum number of modules.

It must make it possible to understand the installation, work on it and evolve it.

Let's Take a Kitchen

It's a simple but revealing example.

A kitchen can bring together several circuits: sockets, fridge, dishwasher, oven, hob, extractor hood, microwave or other specific appliances.

Depending on the power of the appliances, their use and the design chosen, these circuits may require tailored protection and organisation.

To this can be added the needs of the rest of the home: lighting, sockets in other rooms, air conditioning, water heater, gate, outdoor areas, technical equipment or the automation system.

It quickly becomes clear why trying to fit the whole installation into the smallest possible panel can become a constraint.

The number of modules is not an end in itself. It is the consequence of how the installation was designed.

And Home Automation Adds Another Dimension

In a traditional installation, the panel is mainly dedicated to electrical distribution and protection.

In an automated installation, it also becomes a convergence point for some control, communication and technical management functions.

An actuator can control several circuits. An interface can handle communication with another system. A gateway can link different pieces of technical equipment.

The panel then becomes part of the building's technical infrastructure.

It's no longer simply an electrical panel.

It's a convergence point between power, protection, automation and communication.

But Why Leave Empty Space?

This is probably one of the hardest ideas to get accepted.

A panel filled to 100% gives the impression of having been perfectly optimised.

And yet:

Empty space is not wasted space.

Imagine a client adding, a few years later:

• an EV charging point;
• solar panels;
• new air conditioning;
• an extension to the automation system;
• an energy management system;
• or simply new circuits.

If no spare capacity was planned, a relatively simple change can become a much bigger modification.

Space then has to be found, equipment moved, an additional panel added, or part of the installation redone.

A few spare modules left available from the start can therefore avoid much more work later on.

Spare capacity is not waste. It's the ability to evolve.

And Yes, It Comes at a Cost

This is also a question worth asking honestly.

A larger panel can mean more hardware, more space, more cabling and sometimes more installation time.

But reducing the size of the panel purely to cut the initial cost can be a false economy.

The real cost of an installation is not limited to the price of the equipment.

It is also necessary to consider:

installation + commissioning + maintenance + upgrades + intervention time.

A slightly larger panel, properly organised and scalable, can therefore cost more upfront while reducing future costs.

The right choice is not necessarily the one that minimises the number of modules.

It's the one that optimises the overall cost of the installation.

The Problem Often Starts Before the Panel

And this is where the role of the architect and the design office becomes essential.

The electrical panel should not be a decision made at the end of the project:

"We’ve got this space left in this cupboard. The panel will fit here."

Its location should be anticipated from the design stage, taking into account its accessibility, its surroundings and future needs.

In a house, this may mean favouring a garage, a utility room or a technical room rather than a living space or an overly cramped cupboard.

In a commercial building, this thinking can extend to planning a genuine electrical or technical room allowing access, maintenance and the evolution of the equipment.

The panel needs a space planned for it, not a leftover space.

The thinking should therefore start much earlier:

needs → uses → circuits → protection → automation → technical equipment → location → panel sizing.

Because the panel's location also influences its accessibility, its maintenance and the possibilities for future changes.

Do You Always Need a Large Panel?

No.

And that matters.

Bigger doesn't automatically mean better.

A simple, well-designed installation can perfectly well have a compact panel.

The problem arises when you try to impose a small panel before even defining the needs and the architecture.

A villa, a flat, a hotel or a commercial building will obviously not have the same constraints.

And even two similar buildings may require different panels depending on their equipment, their level of automation and their outlook for future changes.

An Electrical Panel Is Sized for Today, But Also for Tomorrow

So, at its core, the question is not:

"What is the smallest possible panel?"

But:

"Which panel genuinely matches the building's needs, its architecture and its foreseeable development?"

A good panel should properly protect the installation, organise the equipment, allow easy intervention and plan for reasonably foreseeable changes.

A small panel is not necessarily a good panel.

And a large panel is not necessarily a better panel.

The right panel is the one that matches the project.

At ExaBuilding, we see the electrical panel as an integral part of the Smart Building's architecture, not as a space that is simply filled once the rest of the project is finished.

Because a building evolves.

Its infrastructure must be able to evolve with it.