Hager ASD420U 20A D Curve 30mA RCBO
Built for selected three-phase loads with demanding switch-on characteristics, the Hager ASD420U 20A D Curve 30mA RCBO brings Type A earth-leakage monitoring and thermal-magnetic protection together. The neutral is switched rather than protected by an additional overcurrent pole.
Designed for Higher Starting Currents
D-curve protection is generally considered for equipment with high starting or magnetising currents; the instantaneous magnetic operating band is typically 10–20 × In. At 20A this corresponds to approximately 200–400A for the magnetic band, not a permissible continuous load. Panel designers should check available fault current, cable sizing and prospective earth-fault loop impedance before specifying this rating.
Key Product Details
This is a D-curve product; it should not be used as a C-curve replacement without checking fault-current and disconnection calculations. A 30mA residual-current threshold may be used for additional protection where the circuit design and regulations require it.
Technical Specifications – Hager ASD420U 20A D Curve 30mA RCBO
| Manufacturer | Hager |
|---|---|
| Part number | ASD420U |
| Device | Electronic three-phase RCBO with switched neutral |
| Poles | 3P+N; 3 overcurrent-protected phases |
| Rated current | 20A |
| Trip characteristic | D curve |
| Residual-current sensitivity | 30mA |
| Residual-current class | Type A |
| Rated breaking capacity | 10kA |
| Module width | 3 modules |
| Mounting | DIN rail; compatible Hager Invicta distribution arrangement (verify board model) |
Understanding B, C and D Trip Curves
B curve: typically 3–5 times rated current for instantaneous magnetic tripping, used for suitable low-inrush circuits. C curve: typically 5–10 times rated current, commonly specified for moderate inrush. D curve: typically 10–20 times rated current, considered for high-inrush loads such as some motors or transformers. Selected model: D curve. These bands describe magnetic tripping, not permissible continuous loading; the installed fault level and disconnection requirements must be verified.
The specific three-phase Hager range in this listing contains C- and D-curve models; no B-curve SKUs are included here.
Related Hager Three-Phase RCBOs
Compare ASD425U (25A, 30mA) or ASX432U (C curve, 30mA) for a different rating or sensitivity.
Browse Hager Protection
Explore the Hager 3 phase RCBO range, Hager three-phase distribution boards and Hager shop.
Install and test in accordance with the Hager instructions and applicable wiring regulations. Verify the product-specific datasheet and board compatibility before ordering.
