RCBO trip testing

[polo1]

It's been a seven day (working) week, and it's all about to start again tomorrow....so apologies if the answer is obvious:dunce2:. I know there are supposed to be no loads connected when testing for trip times, but what impact on readings would there be if loads are connected? I feel as if I should know the answer and I think I may, but my gray matter is so tired, I'm not sure I even remember my name anymore.

Cheers.

 

[Deleted member 9648]

Loads may slow tripping times...remember you are testing the RCD,not the circuit...so test as close as possible to the RCD or even the RCD load terminals with no loads connected...(some RCBO's apparently dont like testing at their terminals and will not trip..MEM i believe,there was a recent thread)
Capacitive loads are especially troublesome,as the capacitor holds a charge when the power is disconnected and fools the tester into thinking the power remains energised after the RCD has disconnected.

 

[Sparky Ninja]

To support wirepuller's post, the additional loads will create "noise" for the tester, giving an inaccurate value (similar to a no-trip setting). You should also consider the risk to the loads themselves when applying the RCD test.

 

[polo1]

Thanks guys. I think I instinctively knew the tripping times might be slower, but it's good to see it confirmed. Hadn't thought about either the noise or capacitive loads - every day's a school day!
Thanks again.