Properly coordinating electrical protections
According to EN 60204-1 and EN 61131-1 and -2, overcurrent protection on SELV/PELV lines must be capable of isolating short-circuits within 10 ms and hazardous overcurrent within 5 s.
Fuses and magnetic circuit breakers, inserted on 24 Vdc lines, have characteristic intervention times that are not suitable for isolating faults with the required speed and accuracy. In addition, the fuses may be replaced with different types, affecting the behaviour of the protection and the safety of the system.
The proper coordination of the circuit in which the overcurrent protection is inserted is very critical, because it must consider the total resistance of the line (connections + wires + protection etc.). For this reason, it is suggested to use power supplies with high overcurrent capability.
The risks are the under-sizing that can cause unexpected switches off in case of load peaks, or over-sizing that can cause the switch off of the power supply and the entire DC line.

CEP the smart current control system
Compared to other electronic protection systems, CEP recognizes and distinguishes the overload from the short circuit, cutting off the faulty circuit in the fastest possible time

The main features are:
• Single-channel modularity avoids waste of space
• Maximum flexibility: it allows setting up to 10 trigger nominal currents from 1 A to 10 A
• Three selectable characteristics curves (Fast, medium slow)
• Settings protected by a tamper-resistant door
• LED for status indication and remote alarm (transistor)
• The load can be activated/deactivated by front push button or by remote control
• The remote control feature can be used to gradually activate the various loads, preventing multiple simultaneous overloads at system start-up
• The manual disconnection, which maintain the load inactive even if the protection is remotely re-activated, prevents from hazardous operating conditions