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Whether it is a renovation or a new installation, with or without GTL sheath, in both cases, it is mandatory to separate the two types of current carrying networks.

Strong current and low current

Diagram of an electricity meter

Introduced by amendment 5 of standard NF C 15-100, the space ETEL (volume dedicated to the electrical installation) integrates the electrical panel and the housing housing (GTL). The latter ensures an organized installation of all the conductors (strong and weak currents) entering or leaving the electrical panel. This space includes:
  • the main breaker on the control panel (1);
  • the technical shelter housing (GTL) (2) ;
  • strong currents in the distribution table (3) ;
  • the weak currents in the communication board (4).

Strict rules for the strong current


The electrical panel groups all the networks known as "strong currents" which supply the electrical equipment of each room: switches, electrical outlets, lighting, heating, etc. All these circuits are protected by divisional circuit breakers (one per circuit) and differential circuit breakers (one per row on the board).
Example for a kitchen: according to standard NF C 15-100, the circuits must converge towards the electrical panel (from the bottom or the top) through a GTL (housing technical sheath) in the volume where the table is present. Beyond this volume, the networks circulate in slits, chutes or behind partitions, counter-partitions and false ceilings.
If the standard provides for a minimum of electrical outlets per room, it is also necessary to provide specialized circuits (rolling shutters, hobs, ovens, water heaters, radiators, etc.) that will supply only one appliance.
As for the power supplied by the energy distributor (6 kV, 9 kV...), it must be chosen according to the electrical equipment of the housing.

Differential and division circuit breaker

  • Two modules are important: the differential circuit breakerl (a) which continuously measures the difference between the value of the incoming current and that of the outgoing current, and the divisional circuit breaker (b), always after the differential, which detects overloads and short circuits.


  • All outlets must be earthed and must be equipped with child safety devices.
  • Their center, always shaped well, has a retractable shutter, which retracts only when you connect an electrical device.

A path dedicated to the weak current

VDI box

Installed closest to the electrical panel, the VDI communication box (voice, data, images) centralizes the weak current circuits that carry the information. These are networks dedicated to telephone, television, Internet, intercom, alarm...
In this box is the DTI (internal termination device), delivery point of the electrical operator through which the information arrives. Some boxes are also equipped with a housing to install the box. This box is the focal point of RJ45 networks (deployed in the home) through which all information (TV, telephone, web...).
As for the electric panel, better think about his installation before getting a VDI box, because not all of them have the same number of patch modules. The latter managing the infrastructure of the network, it is better to have a box to connect the number of RJ45 sockets required to the needs of the occupants. Finally, the cabinets also have the distinction of being distinguished by a classification of grades and type of brewing. Again, it is advisable to learn about these two points before choosing his box.

Communication box

  • VDI communication boxes are able to process three types of signals (telephone, computer and analog and digital terrestrial TV and / or cable) to redirect them, after mixing the data of the box, to the specific jacks that make up the communication network. of the dwelling.

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