Time delayed RCD

Carlosfandango · Sep 10, 2019

My guys were testing a 500ma time delayed RCD today with our Fluke tester, can’t remember the model, 1556???
I had a go and couldn’t get it to trip either. The tester was set to time delayed setting, 500mA, did the 30s countdown but didn’t trip. Am I doing something wrong?? And yes I was definetly testing the load side of the RCD!?

buzzlightyear · Sep 10, 2019

the question how was you testing it ,with 3 probes or two ?

Carlosfandango · Sep 10, 2019

buzzlightyear said:
the question how was you testing it ,with 3 probes or two ?

Tried 2 and 3, no avail!
The RCD is a TP 100amp mccb, 2 years old so doubtful that it’s faulty.

Risteard · Sep 10, 2019

Carlosfandango said:
My guys were testing a 500ma time delayed RCD today with our Fluke tester, can’t remember the model, 1556???
I had a go and couldn’t get it to trip either. The tester was set to time delayed setting, 500mA, did the 30s countdown but didn’t trip. Am I doing something wrong?? And yes I was definetly testing the load side of the RCD!?

Had you it set to the correct type of RCD, i.e. you weren't DC saturating an AC RCD or something like that?

Leesparkykent · Sep 10, 2019

Try it on the circuit not at the terminals. I can’t remember but there was one or two brands that don’t like being tested at the terminals...I don’t know the reasoning behind it, but worth a try.

westward10 · Sep 10, 2019

Did it have a 30s delay.

davesparks · Sep 11, 2019

Leesparkykent said:
Try it on the circuit not at the terminals. I can’t remember but there was one or two brands that don’t like being tested at the terminals...I don’t know the reasoning behind it, but worth a try.

It's memshield 2 MR30 RCBO pods which can't be tested from the terminal screws because the live sensing coil is on the pod which clips on above the terminal.