RCD (30 mA)
2-pole residual-current device (RCCB) · 40 A · trips when 30 mA leaks to earth, within 40 ms · press T to test it monthly · it does not protect against overload: a breaker still has to
Try it on the benchThe lab drops it on an empty bench and opens its datasheet card.
Typical part: RCCB 2P 40 A 30 mA, type AC (e.g. Schneider Acti9 iID, ABB F202)
Pins
- L in
- L out
- N in
- N out
Ratings and limits
| Rated current | 40 A (25 / 63 A versions) |
|---|---|
| Rated residual current IΔn | 30 mA for people; 100–300 mA for fire protection |
| Trip time | ≤ 300 ms at IΔn, ≤ 40 ms at 5 × IΔn |
| Overcurrent | none: put a breaker in series, or use an RCBO |
How to use it
Both L and N go through it. Everything after it must take its neutral from its N out: a neutral borrowed from another circuit makes it trip, or never trip. Press T monthly.
Lessons and builds that use it
- RCD protection: someone touches a live wire (build)
- Real device: water heater, 220 V AC to hot water (build)