ADB3-125-3P Miniature Circuit Breaker

The ADB3-125-3P Miniature Circuit Breaker (MCB) is a robust, high-performance electrical safety device designed for reliable protection in three-phase alternating current (AC) distribution systems. The designation “-3P” (Three-Pole) means it simultaneously isolates and protects all three live phase conductors in a circuit. Belonging to the ADB3-125 series, it has a frame size of up to 125 Amperes, offering thermal-magnetic protection against both overload (due to excessive, long-term current) and short-circuit faults (due to sudden, massive current spikes). It is typically installed on a DIN rail and is suitable for demanding applications in commercial, light industrial, and high-load residential environments where a three-phase power supply requires simultaneous interruption of all phases for safety.

Technical Specification

Feature	Typical Specification	Notes
Poles	3P (Three-Pole)	Protects all three phase conductors (L1, L2, L3).
Rated Current ( $I_{n}$ )	Varies: 80A, 100A, 125A	The specific maximum continuous current rating for the breaker.
Rated Voltage ( $U_{e}$ )	400V AC / 415V AC	Standard three-phase system voltage.
Rated Frequency	50/60 Hz	Suitable for global power systems.
Rated Ultimate Short-Circuit Breaking Capacity ( $I_{cu}$ )	6 kA or 10 kA	The maximum fault current the breaker can safely interrupt once.
Rated Service Short-Circuit Breaking Capacity ( $I_{cs}$ )	$I_{cs}$ is typically 75%-100% of $I_{cu}$ .	The maximum fault current the breaker can safely interrupt multiple times.
Tripping Characteristic (Curve)	Type C (Most Common) or Type D	Defines the instantaneous magnetic trip point:
	– Type C: $5 to 10$ times $I_{n}$	Standard for general inductive loads (motors, fluorescent lighting).
	– Type D: $10 to 20$ times $I_{n}$	Used for high inrush loads (transformers, X-ray machines).
Protection Type	Thermal-Magnetic	Provides overload (thermal) and short-circuit (magnetic) protection.
Standard Compliance	IEC/EN 60898-1 (or similar national standards)	Ensures performance and safety compliance.
Installation	DIN Rail Mount	Standard mounting method for distribution boards.
Terminal Capacity	Designed to accept large conductor cross-sections (e.g., up to $35 mm^{2}$ or $50 mm^{2}$ ).	The size of the wire that can be safely connected.