DORMAN 40 AMP CURVE B 10kA 30mA RCBO TYPE AC KR1PB4030

This Dorman Smith RCBO (Residual Current Breaker with Overcurrent protection) is a high-performance safety device that combines the functions of two separate components—an MCB and an RCD—into one compact unit.

Its primary job is to protect people from electric shock and protect the building from electrical fires caused by overloads or short circuits.

Breakdown of the Technical Specs:

• 40A (Current Rating): This is the maximum continuous current the device can handle.
• Curve B (Tripping Characteristic): This defines how much "surge" current the device allows before tripping.
• 10kA (Breaking Capacity): This measures the maximum "fault current" the device can safely interrupt without being destroyed.
• 30mA (Trip Sensitivity): This is the "life-saving" part. If the device detects more than 30mA of electricity "leaking" out of the circuit, it will shut off the power in milliseconds.
• Type AC (Standard AC): Only detects smooth AC leakage.

Why use an RCBO instead of an MCB?

If you have a fault on one circuit, only that circuit trips. In older boards, using a single RCD for the whole house, a faulty toaster could trip the whole board. An RCBO is an RCD and MCB in one unit, making for a more protected and sleeker board. Unlike the MCB, an RCBO provides shock protection.