RCD vs RCBO: difference and which to choose — GorkyCAD Pro Blog
An RCD protects against leakage current, a breaker protects against overload and short circuit, and an RCBO combines both. Which to install?
What is an RCD
An RCD (residual current device) disconnects on leakage current — damaged insulation or contact. 30 mA for outlets and wet zones.
- An RCD does NOT protect against overload and short circuit — it needs a separate breaker.
What is an RCBO
An RCBO = RCD + breaker in one unit. Protects against leakage and overload/SC. Takes 2 modules instead of 2–3.
Comparison
The choice depends on budget and panel space.
- RCD + breaker: cheaper, more space, easier diagnostics
- RCBO: pricier, compact, harder to tell the trip cause
- One group → RCBO; 3–5 groups → one RCD + breakers
What to choose
Typical apartment: 40A main breaker, 30 mA RCD on outlets and wet zones, separate breakers for lighting and stove. GorkyCAD Pro picks the scheme automatically.
FAQ
RCD trips without reason — what to do?
Check for leakage on old wiring; old outlets or appliances are often the cause.
What RCD rating to choose?
30 mA for outlets and wet zones, 100–300 mA at the input for fire protection.
Can I put one RCBO for the whole apartment?
Not recommended: a trip would cut power everywhere. Split into groups.
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