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RCD types and selection

Residual current devices: types A/AC/B, trip current (10/30/100/300 mA), choosing an RCD for a home, RCD vs RCBO.

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RCD types by leakage current waveform

TypeProtects againstApplication
ACAlternating (sinusoidal) leakageLighting, simple sockets (resistive load)
AAlternating + pulsating DCWashing machines, dishwashers, inverters
BAlternating, pulsating and smooth DCEV chargers, solar inverters

Rated residual current

Leakage currentApplication
10 mAWet rooms (bathroom), children rooms
30 mASockets, appliances (standard for homes)
100 mAGroup circuits, supply (with 30 mA on lines)
300 mASupply, fire protection

RCD or RCBO?

An RCD protects only against leakage; an RCBO protects against leakage and overcurrent/short-circuit. An RCBO saves panel space but costs more.

Rule: one RCD should cover at most 1–2 group breakers, so a trip cuts only part of the home.

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Data is for reference. Final design decisions must follow current regulations and a qualified engineer.