Residual current circuit breaker - selective EFI-4 A S 40/0.3 002064753

Residual Current Circuit Breakers (RCCBs) are a key element of any electrical installation, ensuring the safety of users and protecting equipment. This four-pole model EFI-4 A S 40/0.3 from ETI Polam is a reliable solution designed for selective circuit protection. Its function is to quickly detect and disconnect the power supply in the event of leakage currents, minimizing the risk of electric shock and preventing fires caused by insulation damage.

This circuit breaker is used in a variety of installations – both in residential, commercial and industrial buildings. It will work in TN-S, TN-C-S, TT and IT networks, where effective protection against the effects of short circuits and overloads is important. Thanks to its A S characteristic, this circuit breaker provides not only basic protection but also selective operation, which means that in the event of a failure, only the circuit breaker closest to the fault location will operate – minimizing the scope of power outages.

Construction and mounting

Mounting is done on a standard DIN rail, which simplifies integration with the existing electrical infrastructure. Compact dimensions – width of 4 modules and depth of 68 mm – allow installation even in limited space of the switchboard. Connection terminals allow connection of wires with a cross-section from 1 to 25 mm², both solid and stranded. Additionally secured terminals minimize the risk of accidental contact with live parts during installation and operation.

Technical parameters and application

The circuit breaker is characterized by a rated current of 40 A and a rated differential current of 300 mA. The rated insulation voltage Ui is 500 V, and the rated impulse withstand voltage Uimp is 4 kV – which guarantees high resistance to overvoltage. Short-circuit withstand (Icw) at 10 kA and surge current withstand 5 kA ensure reliable operation even in difficult operating conditions. Operation in ambient temperature from -25°C to +55°C allows its use in a wide range of climatic conditions.

It is worth noting the function of selective protection – thanks to it, the circuit breaker reacts with a delay to short-term current surges, which helps to avoid unnecessary power outages when starting devices with motors or other pulse loads. The test button allows regular checking of the circuit breaker's functionality, and the contact position indicator makes it easy to identify the device's status (on/off). Complies with IEC/EN 61008, which confirms its compliance with European safety standards.