In article .com,
writes:
Testing an RCD (part of a split-load CU) I found that at the rated
current (30mA) it would trip anywhere between 16-17ms to not at all
(even with the meter set to the 2s range). Suspecting the RCD I swapped
in another from a spare box (same make - Clipsal - but almost certainly
different batch as I bought them at different times from different
suppliers). However the other RCD showed much the same behaviour. Both
tripped reliably at 50mA.
Is this typical, or are both faulty? (Is Clipsal crap? :-)

It's not typical -- I normally find they trip within
20ms at the rated trip current (not used Clipsal though).

Is your RCD tester calibration out of spec?

--
Andrew Gabriel