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Zs readings over limits
Former Community Member
Doing an EICR in a block of flats and quite a few of the lighting circuits have excessive Zs readings. All the circuits are on 60898 C10's without RCD protection with readings in the late 2 early 3 ohm range (max permitted 2.19). I know test result fails are generally a code 2 but these are LED panel downlighters with mostly class 2 drivers connected via choc boxes above the suspended ceiling so nothing really accessible. They would all comply with a C6 btw. Just wondered if you'd C2 this resulting in an unsatisfactory EICR
prob a c6 would be better than a b10 considering surge current nuisance tripping (60A vs 50A)
But MCBs are liable to instantaneously trip anywhere within their multiplier range - 3-5x for a B type or 5-10x for a C-type - thus you need to stay below the lower multiplier when you want an MCB not to trip - hence 30A for a B10 (10x3) or 30A for a C6 (6x5).
prob a c6 would be better than a b10 considering surge current nuisance tripping (60A vs 50A)
But MCBs are liable to instantaneously trip anywhere within their multiplier range - 3-5x for a B type or 5-10x for a C-type - thus you need to stay below the lower multiplier when you want an MCB not to trip - hence 30A for a B10 (10x3) or 30A for a C6 (6x5).
