20a rcbo testing strange results.

[krr4]

Hi Guys I have been testing 20a rcbos today on a 3phase tcns cables are all 4mm singles , the readings are all coming out as 19ms both on times 1 and 5 on 0 degress and 9ms on 180 both on times 1 and 5.
found it strange as I thought the time would be smaller on times 5 not exactly the same.
Done with two different testers

 

[trev]

It does sound odd but as long as they're testing out ok don't worry

 

[Guest112]

I've experienced this a lot in testing, also had boards full of RCBOs all the same make and age all give me the exact same readings on each one, it's just one of those things mate

 

[davesparks]

Same make model and age RCBOs should give all the same trip times! The tripping time is not a random thing, it is set in the factory.factory by the manufa

 

[SirKit Breaker]

Nowt wrong with those results.

 

[Engineer54]

Same make model and age RCBOs should give all the same trip times! The tripping time is not a random thing, it is set in the factory.factory by the manufa

I'd have to beg to differ there, you would in fact expect a test at 5 X, trip considerably faster than a test at 1 X. I would also expect a batch of RCD devices of the same make, type and rating, have trip times in a broadly speaking, similar time range, but not necessarily identical.

 

[Meggerman]

I have found same thing also particularly on Wylex RCBO's. You get almost identical trip times on both 1x and 5x test. Had one on Monday, 18ms on both. It is not what you expect and it does not happen with an RCD unit, but it is not a problem is it.