Guys,

Whats the max disconection time, I've got a brandnew MK 30mA RCD which is tripping at 71mS but I thought the max was 41?

Thanks.

200ms at rated trip current
40ms at 500%

For BSEN 61008

1/2 In - No trip
100% In - 300ms
500% In - 40ms

What are you testing it at?

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"Take nothing but a picture,
leave nothing but footprints!"
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"Oh! The drama of it all."
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"You can throw all the philosophy you like at the problem, but at the end of the day it's just basic electrical theory!"
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Rock,
Don`t forget the old BS was 200mS and then there`s delayed RCDs to consider as well

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Regards,
Ebee (M I S P N)

Knotted cables cause Lumpy Lektrik

OP says he just purchased it new so its unlikely to be BS 4293

regards

-------------------------
"Take nothing but a picture,
leave nothing but footprints!"
-------------------------
"Oh! The drama of it all."
-------------------------
"You can throw all the philosophy you like at the problem, but at the end of the day it's just basic electrical theory!"
-------------------------

Good point Rock.

-------------------------
Regards,
Ebee (M I S P N)

Knotted cables cause Lumpy Lektrik

What was the reason for increasing the trip time from 200ms to 300ms. Is to do with nuisance tripping? I don't know the answer but there must be some logical reason.

deapea
The tripping time didn't increase! different standards BS-EN shutting the shop off home

MrP

Thanks Mr.P.
If a an rcd is used as supplimentary protection against indirect contact it must trip in 40ms at 500% of rated trip current(150mA). Now I always found this pretty straight fwd to remember because if 30mA is 200ms then x5 of rated current would be a fith of the trip time, hence the 40ms.
Now this logic doesn't follow for a 300ms rcd. Am I being too simplistic?

And the daft thing is that as BS7671 moves closer to Harmonized standards, some disconnection times (if the DPC is to be believed) are going to change from 0.4s to 0.2s (i.e. 200ms) (e.g. for TT final circuits) - thus an BS EN RCD as 1x rated current will no longer be sufficient, whereas a good old BS one would have been fine!
- Andy.