Ramp test

[Engineer54]

Give me a leakage clamp meter every time, over a MFT ramp test. Far too many variables regarding the accuracy of a ramp test. It's only been relevantly recently, that MFT's ramped up in 1mA steps, on earlier models, it could be anything between 3 to 5mA steps, not exactly very beneficial when fault finding.

Not sure why anyone would find it remotely necessary to ramp test an RCD device after it had passed all it's standard obligatory tests eg X 0.5, X1, X5, ...seems a pointless exercise to me!!

 

[telectrix]

Yes as Richard points out and I touched on too your looking to comply with a trip 'time' when your meter give out 0.5, 1, and x5 rated tripping current. The ramp test is for diagnostic purposes and subject to many factors like existing leakage etc... but dropping all the load off would not have decreased this value as any mA leakage on appliances would be an addition to the result on your meter.

Tripping occurs at 24mA on ramp with loads connected
Tripping occurs at 20mA on ramp without loads connected therefore background leakage due to appliances is 4mA

Im confused why your expressing a value that is not part of the test procedure, if you pass the .5/1/x5 test then the meter has created the correct leakage and the trip times are shown.

is it not the other way round?

 

[Darkwood]

is it not the other way round?

Must have been tired tel.... I knew the right way round in my head my fingers just typed it wrong