£340.95
The ABB DSE203NMB20A30 is a compact and reliable three-phase plus neutral electronic residual current circuit breaker with overcurrent protection (eRCBO). It combines overload, short-circuit and earth leakage protection within one device, helping improve electrical safety while reducing the number of separate protective components required inside a distribution board.
As part of the ABB DSE203N electronic RCBO series, this protective device is designed for commercial, industrial and building-services electrical installations. Its combined protection functions simplify panel design, installation, testing and fault diagnosis while providing dedicated protection for the connected circuit.
The DSE203NMB20A30 has a rated current of 20 A, a Type B tripping characteristic and a rated residual operating current of 30 mA. Its Type A residual current detection responds to sinusoidal AC and pulsating DC residual currents, making it suitable for lighting, heating, electronic equipment, control systems and other loads with relatively low starting currents.
An electronic RCBO protects an electrical circuit against several common fault conditions. Its thermal protection responds to sustained overloads, while its magnetic mechanism provides rapid disconnection during short-circuit events. The electronic residual current system also monitors the current balance between the live conductors and neutral.
When leakage current flows to earth and reaches the specified operating threshold, the ABB DSE203NMB20A30 disconnects the protected circuit. Combining these functions in one device provides individual residual current protection and can reduce the likelihood of a fault unnecessarily interrupting unrelated circuits.
Type A residual current protection detects both sinusoidal alternating residual currents and pulsating direct residual currents. This makes the DSE203NMB20A30 suitable for circuits containing electronic controls, switch-mode power supplies and other equipment that may generate pulsating DC leakage currents.
The Type B tripping characteristic is designed for circuits where high starting currents are not normally expected. It is commonly applied to lighting, resistive heating, socket circuits, electronic equipment and control systems, subject to the requirements of the electrical installation design.
| Current | 20 A |
|---|---|
| Phase | Three Phase |
| Function | 3P+N electronic residual current circuit breaker with overcurrent protection (eRCBO). |
| Residual Current Type | Type A. |
| Protected Poles | 3 poles plus neutral (neutral unswitched). |
| Operating Characteristic | Instantaneous trip. |
| Connection Type | Bottom power supply connection, neutral terminals on left. |
| Terminal Capacity | Busbar 10 mm²; Rigid conductors 1–25 mm²; Flexible conductors 1–16 mm². |
| Rated Cross-Section | Solid-core 1–25 mm², multi-wired 1–16 mm². |
| Electrical Endurance | 10,000 cycles. |
| Mechanical Endurance | 20,000 cycles. |
The ABB DSE203NMB20A30 protects three-phase plus neutral electrical circuits against overloads, short circuits and earth leakage faults.
The DSE203NMB20A30 has a rated current of 20 A and a Type B overcurrent tripping characteristic.
The 30 mA value is the rated residual operating current. The RCBO disconnects the protected circuit when earth leakage reaches its operating threshold, providing additional protection against electric shock.
This RCBO uses Type A residual current protection, which detects sinusoidal AC and pulsating DC residual fault currents.
A Type B tripping characteristic is intended for circuits with relatively low inrush currents, including lighting, resistive heating, electronic equipment and control circuits.
ABB DSE203N electronic RCBOs are widely selected by electrical contractors, panel builders and industrial engineers for dependable circuit protection, efficient installation and reliable operation in modern low-voltage distribution systems.
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LED Controls is a specialist distributor of factory automation and industrial controls, supplying OEMs, machine builders, panel builders and end users throughout the UK and worldwide. As a trusted UK distributor for many of the world’s leading automation manufacturers, we provide industrial control products, technical expertise and bespoke automation solutions backed by outstanding customer service.
2025 has been a big year for LED Controls, and our blog has expanded accordingly. We've covered a wide range of topics across industrial control and factory automation this year. From core technology explainers and new product releases to panel building best practice...
2025 has been a big year for LED Controls, and our blog has expanded accordingly. We've covered a wide range of topics across industrial control and factory automation this year. From core technology explainers and new product releases to panel building best practice...