Electrical equipment

The differential switch only detects current leakage (difference between phase and neutral) and protects against electrocution. It does not protect against overloads or short circuits. The differential circuit breaker combines both functions: it detects current leaks AND protects against overloads/short circuits. A differential circuit breaker therefore replaces a differential switch + a conventional circuit breaker. It's more compact, but also more expensive.

The cable cross-section depends on several factors: the power of the devices to be supplied, the length of the circuit, and the type of protection (circuit breaker). For a lighting circuit (10A), use 1.5 mm². For 16A sockets, 2.5 mm² is mandatory. For powerful appliances (32A hob), use 6 mm². For longer lengths (>30m), increase the cross-section to compensate for voltage drops. Always comply with the NF C 15-100 standard, which precisely defines these dimensions.

The AC type differential detects sinusoidal alternating fault currents (the most common). The differential type A also detects fault currents with a DC component (produced by induction hobs, washing machines, electric vehicle chargers). Standard NF C 15-100 requires at least a type A differential to protect stove and washing machine circuits. For optimum protection, choose type A, or even type F (even more sensitive) for recent installations.

The general rule is the upstream/downstream rule: the total current rating of downstream circuit breakers must not exceed the current rating of the earth leakage switch. For a 40A differential, you can install up to 8 circuit-breakers (without exceeding 40A in total). However, according to the standard, the number of circuits per differential must not exceed 8 in residential applications. In practice, we generally install 5 to 8 circuits per 40A differential.

A modular lightning arrester protects your installation against power surges caused by lightning or switching on the electrical network. It is mandatory in departments where the keraunic level (lightning density) exceeds 25 days of thunderstorms per year, and in all areas where the power supply is partially or totally overhead. Although not mandatory, it is strongly recommended to protect your sensitive electronic equipment (computers, household appliances). The surge arrester is installed at the top of the panel after the service circuit breaker.

Yes, it's perfectly possible to mix brands in an electrical panel, provided all devices are in standard modular format (module width = 17.5 mm). Brands such as Legrand, Schneider, Hager, ABB and Siemens all comply with this standard. You can therefore combine a Schneider circuit-breaker with a Hager earth leakage switch without any problem. Please note, however, that feeder combs are sometimes brand-specific and may not be compatible with each other.

A properly sized electrical table can last 25 to 30 years without any problems. Circuit-breakers and differential switches have a service life of 10,000 to 20,000 operations, depending on the model. We recommend that you test your differentials every month using the test button, and check that the connections have not overheated. Wall sockets and switches generally last 15 to 20 years under normal domestic use. Replace any device that shows signs of wear (hard mechanism, overheating, burn marks).

The circuit-breaker rating must be matched to the cable cross-section, not to the power rating of the device. The standard requires: 1.5 mm² cable = maximum 16A circuit breaker (for lighting, 10A is sufficient), 2.5 mm² cable = maximum 20A circuit breaker (for sockets, 16A in general), 6 mm² cable = 32A circuit breaker, 10 mm² cable = 40A circuit breaker. Never oversize the circuit-breaker in relation to the cable, otherwise the cable is no longer protected against overheating and the risk of fire.

The va-et-vient is a classic wired solution for controlling lighting from two different points. It requires 3 wires between the two switches (shuttles). The dimmer switch is an electromechanical relay that controls lighting from several points (3, 4, 10...) with simplified wiring: each push-button requires only 2 wires. The remote switch is mounted in the electrical panel or in a junction box. This is the preferred solution when you have more than 2 control points.

An installation is considered up to standard if it complies with the norme NF C 15-100 in force at the time of installation (no retro-compliance required). Main checkpoints: presence of 30mA differentials on all circuits, circuit breakers adapted to cable cross-sections, earthing of all circuits, specific protection in bathrooms (safety volumes), presence of a lightning arrester if mandatory in your area. For property sales, an electrical diagnosis is mandatory for installations over 15 years old. For complete compliance, call in a qualified electrician.