Split-load Dual RCD Board
Main switch feeding two 30 mA RCDs, each protecting a bank of MCBs.
● Line● Neutral● Earth
Tap any wire, switch or device to see what it is.
Useful Information
One fault trips a whole side. Toggle a trip to see which circuits go off.
Important to know
- Split lighting and sockets across both RCDs to avoid total loss of lighting (314.1).
- Consider cumulative earth leakage — max 30% of IΔn per RCD (531.3.2).
- Domestic CUs need a non-combustible enclosure (421.1.201).
BS 7671:2018+A4:2026 references
314.1421.1.201531.3.2
Study notes paraphrased — check against your copy of BS 7671.