How to read and understand an electrical panel ?

The electrical panel plays an essential role in the heart of your home. In a box, it centralizes all the electrical circuits, distributes the electricity as needed, protects the installation, the equipment and the inhabitants against any electrical anomaly. You don’t understand anything about it? Rest assured, an electrical panel is not very complicated. We explain the different elements that make it up and their role in the house…

The electrical panel: presentation

The electrical panel is generally installed near the electricity meter. It comes in the form of a plastic box. Inside are rows of metal rails that support the various distribution and protection devices, circuit breakers and switches. Thanks to these small rails, your installation is perfectly organized. Places are provided to add additional modules, depending on the needs of your installation.

For your protection: the 30 mA differential device

The NFC 15-100 electrical standard requires the electrical panel to be equipped with a personal protection system.

The differential switch protects people

The differential switch is mandatory. Your electrical panel must have at least two, one of which must be type A (for washing machine and hob). Their role is to identify abnormal voltage differences. Each differential switch is located on a rail, at the beginning of a row which has a maximum of 8 divisional circuit breakers, which complete its action. As soon as it detects an electrical leak, the differential switch puts the installation in safety to avoid any accident. It trips and cuts the current of a whole row of the board. In the event of an electrical leak, you are thus protected from the worst: electrification or even electrocution!

There are three types of differential switches:

  • Type A for powerful appliances (washing machine, hob, electric vehicle charging socket, etc.);
  • Type AC for sockets and lights;
  • Type Hi (high immunity) for sensitive equipment to be protected from cuts (freezer, computer equipment, alarm, etc.).

Branch circuit breakers monitor circuits

Installed on the row of a differential switch, branch circuit breakers have an additional circuit protection function. Each is connected to a single circuit, which it monitors for any anomalies. At the slightest short-circuit or in the event of an overvoltage, the branch circuit breaker cuts off the current in its circuit; his joystick lowers. This allows you to easily find the cause of a problem. After having thus located the device in question, you just have to go up the joystick to restore the current.

There are several powers of branch circuit breakers:

  • in 16 A (8 sockets) for lighting, electric shutters;
  • in 20 A for electrical outlets (6 outlets), household appliances, heating (4500 W circuit);
  • in 32 A for the hob.

NB : branch circuit breakers have become mandatory: they replace fuses, or circuit breakers, which are now prohibited in both new builds and renovations.

The differential circuit breaker secures the equipment

Its presence is not systematic. But it has the advantage of providing more complete safety than the differential switch, since it protects both people and equipment. The differential circuit breaker is essential for very sensitive equipment. Like the differential switch, it cuts the current when an anomaly exceeds a threshold of 30 mA, beyond which human health is in danger. It not only detects current leakage, but also overloads and short circuits. According to its power in amperes, the circuit breaker is dedicated to different types of circuits:

  • 2 A circuit breaker: VMC (controlled mechanical ventilation), bell, off-peak contactor;
  • 10 A circuit breaker: lighting, boiler, heated towel rail, rolling shutters, etc.;
  • 16 A circuit breaker: power sockets…;
  • 20 A circuit breaker: household appliances (washing machine, oven, dishwasher, freezer, etc.);
  • 32 A circuit breaker: kitchen hobs, cooker, etc.

NB : This equipment being more expensive than a differential switch, it is reserved for more sensitive equipment, such as a chest freezer.

The surge arrester protects the electronics

This module protects your electrical installation, in particular telecommunications and electronic devices, in the event of overvoltage linked to lightning. A storm can indeed cause an electrical overload of several thousand volts in the space of a flash! It sits close to the main circuit breaker and is grounded to safely discharge surges. If your area is prone to thunderstorms, an electrician can tell you the recommended wattage based on their wattage.

electric combs

No, you are not in the hairdressing section… Electric combs are an element that is easy to spot in the electrical panel. With their small teeth, they connect the different elements of the painting. They are also called electrical connectors. Their mission: to “bridge” the elements of the painting by connecting them with small copper wires. Identify their color: blue for neutral, black for phase.

The vertical combs

These vertical connectors are in phase and neutral connection. At each row of the switchboard, they distribute the power supply to differential devices (mandatory placed at the start of the row). If your electrical panel has a single row, no vertical comb is needed.

The horizontal combs

Horizontal connectors are placed above other elements. They are two on each row. Their role is to connect the differential switch with the branch circuit breakers of their line. In a single-phase installation, the electrical panel has two horizontal combs, either in a single block or in two rows: a neutral (blue) and a phase (black).

Attention : In combs, some slots are sometimes left free; in these locations, do not leave the teeth bare, this can present a danger for you and your board. It is necessary to protect them with an electric comb shutter.

The ground connection terminal

The earth terminal is a very useful element of your electrical panel: it is what evacuates any current leaks to earth. With the earth connection terminal block, it generally makes the connection between the outdoor part and the underground part of the earthing installation. This terminal block centralizes all the circuits of the installation requiring earthing.

Distribution terminals for phase and neutralmeanwhile, connect the differential devices to the phase and neutral wiring that come from your general circuit breaker.

Conductors: cables and electrical wires

The switchboard centralizes all the wiring and electrical wires in your home, which carry electricity. These conductive elements are organized by the combs of the board. They do not appear directly on the electrical panel, but all are connected to it.

Additional modules

In addition to the mandatory elements already covered, you can add modules to the table that correspond to specific needs.

  • We have already mentioned the lightning arrester, which protects your installation from overvoltages caused by lightning. It is compulsory in certain more vulnerable regions.
  • The day/night switch : if you have the peak hours/off-peak hours option. It is he who triggers the hot water tank during off-peak hours… and saves you money.
  • The load shedder : thanks to it, you can exceed the electrical power of your subscription without risking a power cut. To succeed in this effort, the load shedder manages the circuits itself, cutting some of them so that you can use others, according to your needs… On the panel, it is installed after the main circuit breaker and after the differential devices.
  • The contactor : it allows you to control the same lighting circuit from different points in your home.
  • The modular dimmer : it works like the remote switch and also manages light intensity dimmers. Some models have a timer or memory dimmer…
  • The timer relay, or timer: with this system, your lights turn off automatically after a programmed period of time. In certain passageways where you forget to turn off the light, this allows you to save some electricity.

Keep in mind that it is best to entrust the installation of an electrical panel to a professional. But if you understand your board, it will be easier to fix some problems, safely.

Leave a Comment