Differential (Residual Current) Circuit Breaker EFI-P4 40A 4P 30mA Type A 10kA

The Differential (Residual Current) Circuit Breaker EFI-P4 40A 4P 30mA Type A 10kA combines residual-current detection with overcurrent protection in a single four-pole device. It is rated for 40 A nominal current and provides 30 mA residual sensitivity with Type A detection, which covers alternating current leakage and pulsating direct current faults. The unit features a breaking capacity of 10 kA and is designed for installation in household and light-commercial distribution boards to reduce risk of electric shock and fire due to earth-leakage currents.

Advantages

The device integrates residual-current monitoring and short-circuit/overcurrent protection, reducing component count in a distribution board and simplifying wiring. Type A sensitivity improves detection of AC and pulsating DC leakage that can occur with modern electronic loads and appliances. A 4-pole design enables simultaneous disconnection of all conductors in three-phase or three-phase-with-neutral systems, improving safety during fault conditions. The 10 kA breaking capacity ensures the device can interrupt typical fault currents found in domestic and small commercial installations.

Suitable for

• Three-phase or single-phase household electrical distribution with neutral
• Small commercial premises and light industrial installations
• Circuits with electronic equipment that may produce pulsating DC leakage
• Protection of socket outlets, lighting circuits and small motor loads

When it may not be suitable

This unit is intended for installations where a 40 A nominal rating and 30 mA residual sensitivity are appropriate; it is not suitable where higher continuous currents or different sensitivity levels are required. It also does not provide selective discrimination with upstream protection unless coordination is verified; in larger installations additional protective coordination may be necessary.

Key specifications

• Rated current: 40 A
• Pole configuration: 4 poles (4P)
• Residual sensitivity: 30 mA
• Residual current type: Type A (AC and pulsating DC detection)
• Breaking capacity: 10 kA

How to use

Install the device on a standard DIN rail inside the distribution board according to local wiring regulations. Connect line and neutral conductors to the labeled terminals, ensuring correct phase sequence for three-phase circuits. Verify that upstream and downstream protection devices are compatible and that the device is mounted where tripping is accessible for maintenance. Test the residual-current function after installation and at regular intervals using a test button or an appropriate test instrument following local safety standards.

What to consider before purchase

• Confirm that 40 A rated current matches the intended circuit load and that upstream breakers provide proper coordination
• Ensure Type A residual detection is required for connected electronic equipment
• Verify that a 4-pole device is suitable for your distribution layout (three-phase with neutral)
• Check available panel space and DIN-rail capacity for a 4P device

Usage recommendations

For safe operation, combine the differential circuit breaker with correctly rated upstream overcurrent protection and follow local electrical codes. Perform functional tests after installation and during regular maintenance, and replace the device if it shows signs of mechanical or electrical failure.