Intermittent RCD tripping can be a frustrating puzzle, as I recently found out on a call-out where a split-load board protected by two RCDs was constantly tripping at random times. Using an earth leakage clamp meter, I discovered a collective background leakage of 20mA on each RCD, bringing the total system earth leakage to 40mA. Because standard 30mA RCDs can become sensitive and trip once background leakage from everyday appliances pools together, any minor surge was pushing them past their tipping point. To provide a permanent fix, I upgraded the consumer unit to individual RCBOs on every circuit, which stopped the leakage pooling, isolated each circuit independently, and completely resolved the nuisance tripping for a stable, future-proof installation.
