Hager ASZ420U 20A C Curve 300mA RCBO
The Hager ASZ420U 20A C Curve 300mA RCBO is a 10kA three-phase RCBO with C-curve magnetic response and 300mA Type A sensing. Its role should be assessed in the context of the whole installation, including fault protection and any downstream 30mA devices.
Understanding the 300mA Rating
This 20A / 300mA combination is for protection designs where a 300mA residual threshold is appropriate. It must not be described or relied on as the same level of additional shock protection as a 30mA RCBO. A 300mA rating is not a substitute for 30mA additional protection on circuits where that is required.
Distribution-Circuit Selection
Type A sensitivity does not by itself establish suitability for every EV charger or power-electronic load; follow equipment instructions. This is a C-curve product; substituting D curve changes the instantaneous-trip band and requires design verification.
Technical Specifications – ASZ420U
| Manufacturer | Hager |
|---|---|
| Part number | ASZ420U |
| Device | Electronic three-phase RCBO with switched neutral |
| Poles | 3P+N; 3 overcurrent-protected phases |
| Rated current | 20A |
| Trip characteristic | C curve |
| Residual-current sensitivity | 300mA |
| 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: C 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 ASZ425U (25A, 300mA) or ASD416U (D curve, 30mA) for a different rating or sensitivity.
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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.
