The 5 times RCD test was never part of BS 7671 — yet it became one of the most repeated habits in our industry. This article explains where the test really came from, why it caused so much confusion, and how electricians should verify RCD and RCBO performance correctly under the latest wiring regulations.

An RCBO is a Residual Current Breaker with Overcurrent protection. In simple terms, it combines the function of an MCB and an RCD in a single device. That means it protects against two things: