RCD test button

[PB1]

If an RCD passes the manual push button test, is this any indication that it will disconnect in the required time under actual fault conditions?

 

[ringer]

Not an indication that it will disconnect in the required time, only an indication that it can disconnect.

 

[Guest112]

that only proves that it functions but doesnt prove it will disconnect in the required time

 

[MarkieSparkie]

It only proves the RCD is functional, but not to what degree.

 

[funkeyfarmer]

As said above it only proves that it fuctions and it is free to trip. the rcd should be tested before the test button is pushed to make sure it can trip under fault conditions

 

[GLENNSPARK]

yes and after doing the 6 tests for RCDs...that is x1/2..x1..and x5 and again at 180 always do the manual test by depressing the test button....if the RCD fails to operate 1st time by manual test then it should be condemned.....by the way.....failure to do the manual test after the 6 tests above when being assessed on the 2392 and 2391 will be marked against you......

 

[clicon357]

If I can add my tuppence worth.........some of the 3 phase RCD's won't trip on the test button if there is no neutral (some will of course, depends on the make). It can make you think the RCD is faulty. For the ones that don't you can usually add a big resistor from the unused neutral terminal to one of the phases and then the trip button works. It is as others have said just an indicator that the "mechanics" of the RCD work not that the tripping times are in fact OK, for that its a proper RCD tester job

 

[Rob Smith 643]

yes and after doing the 6 tests for RCDs...that is x1/2..x1..and x5 and again at 180 always do the manual test by depressing the test button....if the RCD fails to operate 1st time by manual test then it should be condemned.....by the way.....failure to do the manual test after the 6 tests above when being assessed on the 2392 and 2391 will be marked against you......

What's the theory behind this Glennspark, I.e. why the test button last. I have been told this before but can't recall the answer and now its doing my head in!

Cheers,

Rob

 

[Rob Smith 643]

Error.

 

[bartkusal]

What's the theory behind this Glennspark, I.e. why the test button last. I have been told this before but can't recall the answer and now its doing my head in!

Cheers,

Rob

You doing it the last, because in real life the rcd is not pressed quarterly as it should to move mechanical parts inside it as they can stick, and by pressing it before time tests, you loosen the mechanical parts and time tests after that is not credible, as in real fault situation there will be no one to press the button before the fault.

 

[GLENNSPARK]

What's the theory behind this Glennspark, I.e. why the test button last. I have been told this before but can't recall the answer and now its doing my head in!

Cheers,

Rob

its functional testing....
functional testing is the last testing undertaken before handover....
it should be remembered that the person to whoom it may concern...such as a tennant/occupier, homeowner, the person ordering the work ect should be shown how to perform a `manual/functional test` of an RCD/RCBO and how to reset ect. A test quarterly sticker should be placed on enclosures where RCDs are present and the person ordering the work made aware of the importance of testing quarterly to keep the mechanism free.