Rcd faulty ?

[huntos33]

Hi all

Been to a house today to carry out a PIR mem split load board 100amp ms / 30ma rcd on a tt system , when carrying out no trip earth loops the rcd trips. I ramp tested the rcd and its tripping in 18ms, anyway i bridged out the rcd all e loops are fine. however the client would like a shed supply installed obviously on the rcd side would this be a faulty rcd ? hence tripping on e loop ?

If so i have to change the board as the trip is now discontinued

 

[Strima]

What meter are you using? I know there are problems with some Megger 1700 range tripping on the no trip setting.

 

[telectrix]

test the RCDvfor trip times at x1 and x5. if within limits, ( 200mS) then OK.

 

[huntos33]

What meter are you using? I know there are problems with some Megger 1700 range tripping on the no trip setting.

Using a robin kts 1625

 

[SparkyBrad]

If it's a 30mA RCD it has to not trip at half the current ie 15mA for a period of 2 seconds. if it doesn't trip then it is not a failure. I suspect it won't trip. It passes by the skin of it's teeth!!

 

[huntos33]

Cheers guys never had one trip on no trip before , well not that i can remember all is well then so it would seem.

 

[huntos33]

Reading that it should trip on ramp near its fault current so would 18ms on ramp be to low ie possible future nussence tripping ?