RCD not tripping at 0 Degrees

[MarkieSparkie]

explain ramp test for me please

RCD's generally trip anywhere between 50% and 100% of their nominal rated current it is common and perfectly normal for a 30mA RCD to trip between 15mA and 30mA but on average in the low twenties of mA.

On most RCD testers with a ramp function, when you press the test button, the tester progressively increases (ramps up) the circuit leakage current in 1mA steps, until such time as the RCD trips, you can then read the display which gives the value of current in mA at which the trip occurred.

When ramp testing, if there is already an existing leak on the circuit this can reduce the reading further as the existing leak will just add to the meter ramp effect giving a false early trip value.

If their is no existing leakage on the circuit, then a reading less than 15mA is likely to be prone to nuisance tripping and you should consider replacing the RCD.

This test, like all RCD tests, should be carried out directly at the RCD load side (output) terminals with the final circuit disconnected or at least with all loads removed.



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[Farmelectrics]

thanks markie so the rcd test is measured in mili seconds and the ramp test in mili amps but why and when are you asked to do a ramp test been testing for good while now allways just done x1/2 x1 x5 tests never been asked to do a ramp test could you explain when a ramp test would be required

 

[dagrat]

A ramp test is used in fault finding to ascertain whether it is the rcd that is over sensitive or an actual fault is present.
There is no requirement to enter this finding on any test certificate, just another tool to be used in testing and fault finding.

 

[Farmelectrics]

thanks dagrat never come across it before

 

[Farmelectrics]

dagrat does this problem expose the theory of nusiansce tripping or is there such a thing of nusiance tripping

 

[dagrat]

Nuisance tripping is a general term that refers to many causes, but that would definitely include the tripping of an over sensitive red, so yes really.

 

[moddeydhoo]

test a range from below ma trip is, to above could be a 30 ma trip trips at 40 ramp test will tell you if it works or not

 

[Farmelectrics]

moddey dont understand can you explain more clearly

 

[dagrat]

Must admit that confused me too..

 

[MarkieSparkie]

test a range from below ma trip is, to above could be a 30 ma trip trips at 40 ramp test will tell you if it works or not

Gosh! Where is i=p/u we need him as an interpreter. LOL

 

[moddeydhoo]

i just do it, do not need to think it is so easy i do not know the exact range in which individual meters work, if a trip does not work on a standard test or trips at 50%, i would do a ramp test on 30ma trip set at 30 on ramp test , meter will then start at 0ma and rise to maybe 50 or 60 ma. If it trips at 50ma, you can say it is tripping out of range and is faulty, if trips at 20ma, it is under range and faulty, if it does not trip at this setting, i would turn it up to 100ma if trips , still over range and faulty, if does not trip, trip is more than likely ffffeeeddd. so you know what to write on the ecr