The Content Of The Article:

Protection of electrical circuits

Any short circuit, or excessive power demand, causes a rise in the temperature of the conductors, which can trigger a fire. It is therefore essential to protect electrical circuits against this risk. This is the role of fuses and circuit breakers, especially in a pre-wired electrical panel.

Upstream protection

The distributor (EDF in France) places a series of breakers between theproduction unit (hydro or thermal power plant) and multiple points of use. For each subscriber, it requires the installation of a main breaker called "branch", or "subscriber", which protects the meter and prevents a multi-subscriber breaker from being triggered when an incident occurs in one of them.
It prevents the recovery of an incident occurring on an installation to the entire network.

Protection of electrical circuits

In theory, an installation could be satisfied with this simple protection device. In practice, it is not desirable that an incident, occurring on one of the circuits, results in a general "disjointing", thus in a total break, plunging the whole house in the darkness.
Each circuit must therefore be protected by a cut-off device, often placed on one of the two conductors only (single phase). The ideal is, however, a bipolar protectionthe neutral being also an active conductor.

Cartridge cutouts

A cartridge cut-out

A cartridge cut-out

The system is composed of a fuse holder which comprises a rocker device or an internally threaded well into which an internal fuse cartridge is inserted. This one "grid" when a overload or an incident occurs on the circuit, causing a rise in temperature. You must then replace the cartridge after eliminating the cause of the incident. It is practically impossible to cheat, the size (diameter and length) of the cartridge being a function of its level of protection (expressed in A), and the fuse holder can not receive an amperage cartridge higher than that of the circuit for which it is intended.
To easily identify the relevant cartridge, some models have we have seen a " seeing In fact a red pellet, which comes off when the cartridge is burned out.
The fault must be reduced and replaced.

Divisional circuit breaker

Divisional circuit breaker

None of the aforementioned systems provides a perfectly reliable protection or completely accurate. Only circuit breakers have this quality. Some of them also offer differential protection, essential to protect returns to the earth. Manufacturers have developed mini-breakers, often called " divisional Since they can replace fuses and protect each circuit, or even different parts of the same circuit. They integrate perfectly with contemporary subscriber tables, for which they were designed (reserve locations are often provided). They fulfill both the function of protection and manual control of the circuits.
Any installation creation, or any renovation is prioritized by the development of a distribution panel equipped with circuit breakers, the standard NF C 15-100 even imposing the adoption of 30 mA circuit breakers for a number of circuits:

  • power outlets intended for the power supply of mobile devices or switch-controlled power outlets;

  • the circuits planned for the washrooms;

  • the outlets of applied wires in the kitchen.

Pre-wired electrical cabinet

This pre-wired box of recent generation allows the protection of all the circuits of the electrical installation of a dwelling or a dwelling of average size: the protection of the goods is ensured by 8 circuit breakers division, the protection of the people by 1 differential switch 30 mA according to standard NF C 15-100. It is noted that 3 pre-wired locations are provided to allow a possible divisional, the protection of people by 1 differential switch 30 mA in accordance with standard NF C 15-100. We note that 3 pre-wired locations are planned to allow a possible extension of the installation by 3 new circuits.

Pre-wired electrical cabinet

Pre-wired electrical cabinet

(photos / visuals: © DIY-Prod, except special mention)

On the same topic

  • Questions answers
    • Can rigid cables be replaced by flexible cables?
    • ERDF box degraded: who is responsible?
    • Which electrical outlets should be connected to the earth?
  • products
    • Differential Switches and Circuit Breakers: Perfect Protection of the Electrical System (Debflex)
  • DIY tips
    • The different types of switches

This may interest you


Video Instruction: How to Protect an Electrical Circuit | Electricity