RCD Trip Time Check
Check measured ×1 and ×5 RCD trip times against the limits in BS EN 61008 / BS 7671 for general (instantaneous) and S-type (selective) RCDs.
Limit 300 ms
Limit 40 ms
Limits per BS 7671 / BS EN 61008-1.
Limits
For type AC and type A general (instantaneous) RCDs: ×1 I∆n must trip within 300 ms and ×5 I∆n within 40 ms. S-type (selective / time-delayed) RCDs are allowed longer: ×1 within 500 ms, ×5 within 150 ms.
Why it matters
An RCD that fails to trip within these times no longer provides additional protection against indirect contact (BS 7671 Reg 415). Record the measured times on every periodic inspection.
Used in
- EICR — recorded per RCD on Schedule of Test Results.
Reference
BS EN 61008-1; BS 7671:2018+A2:2022