A disconnector is a device that allows you to separate circuits but does not allow you to switch and protect them. The circuit breaker, on the other hand, can protect, switch, and separate circuits. In other words, the circuit breaker is a safety device that protects the circuit and people through automatic operation, while the disconnector is a switching device that allows a circuit to be opened or closed without an automatic protection function, for example, during maintenance or modification operations within the electrical installation.
What is the difference between a circuit breaker and a disconnector?
Circuit breakers and disconnectors have many differences that will help you compare them and choose which one is most appropriate for your needs. In summary, here are the specific characteristics of each of these two electrical devices:
The function of the circuit breaker is to:
- Protect against overloads and short circuits
- It can be equipped with a differential part to protect against leakage currents
- It cuts power automatically in case of a problem, such as a short circuit or overcurrent
- It can be reset and reused after the power has been cut
The disconnector has the following functions:
- It allows an electrical circuit to be separated from its power supply
- It has no breaking capacity; it cannot cut power in case of a fault
- It must be used when not under load, i.e., when the downstream devices are not operating
- It is used to isolate part of the electrical circuit so work can be carried out safely
How do I choose between a circuit breaker and a switch-disconnector for my electrical installation?
A switch-disconnector is generally installed at the head of the electrical panel. It isolates a circuit when not under load, enabling the circuit to be locked out and work to be carried out downstream of this device in complete safety.
The interruption function allows a live circuit to be opened. On the other hand, a magnetothermal device like the circuit breaker protects a circuit against overcurrents, overloads (thermal part), and/or short circuits (magnetic part).
The choice between these two devices primarily depends on your priority need: automatic protection or manual isolation. For a domestic installation, combining both often provides an optimal level of safety.
The voltage category and nominal current also influence your selection. Always check compatibility with your existing electrical panel before purchase.
The disconnector function is also associated with other products, for example:
- The iSW, INS, Vario, and Mini-Vario range switch disconnectors for commercial and industrial applications.
- Switch disconnectors in enclosures for proximity switching near machines in industrial environments but also near outdoor air conditioning units.
What about the trip circuit breaker ?
The trip circuit breaker combines the advantages of several electrical devices. Its role is to ensure both the functions of a switch and a conventional disconnector. Its particularity lies in its integrated tripping mechanism. The basic role of the switch disconnector is thus extended thanks to this additional functionality. This mechanism allows automatic opening of the circuit in case of detected anomaly.
Unlike circuit breakers, trip circuit breakers do not offer complete protection against overloads. They intervene only on external command or specific signal. Electricians often use them in industrial installations requiring enhanced security. Installing a trip circuit breaker requires good knowledge of current electrical standards.
The main difference from a standard circuit breaker is its ability to react remotely. This feature is very valuable in environments that are difficult to access. For electricity professionals, this type of electrical device represents an excellent compromise between safety and flexibility of use. In addition, newer models incorporate very practical visual position indicators: green for open circuit and red for closed circuit.
When choosing your electrical equipment, precisely evaluate your protection needs. A trip circuit breaker is perfectly suited for applications requiring a controlled cut-off. Its slightly higher cost is justified by its increased versatility in complex installations.
