RCD Tripping Intermittently

[Marvo]

The earth leakage tester I've found myself using the most is a very small, very light Chauvin Arnoux flexible clamp tester which isn't actually marketed as a leakage current clamp but it performs remarkably well with leakage currents as low as a couple of miliamps. Having a flexible clamp makes it very handy because it's easier to get it around multiple wires at once such as supply tails etc. It also has a remarkably good frequency range which means it's surprisingly accurate for most carrier frequencies of motors driven by a VFD and it would probably work will on lighting circuits supplied by a dimmer whereas many other clampmeters won't. A few other things in its favour are it's true RMS, it's got a high hold feature and you can switch off the auto power down so it can be left in a DB or panel overnight to record the maximum current event. Finally it was very cheap.

Here's the manual and data.
http://www.chauvin-arnoux.at/download/digiflex/ba_ma400d.pdf

Testmeter have it available on their website for 134 of you UK pounds (ex VAT) before forum discount. http://www.test-meter.co.uk/chauvin-arnoux-digiflex-ma400d-250mm-sensor/

 

[shanky887614]

The earth leakage tester I've found myself using the most is a very small, very light Chauvin Arnoux flexible clamp tester which isn't actually marketed as a leakage current clamp but it performs remarkably well with leakage currents as low as a couple of miliamps. Having a flexible clamp makes it very handy because it's easier to get it around multiple wires at once such as supply tails etc. It also has a remarkably good frequency range which means it's surprisingly accurate for most carrier frequencies of motors driven by a VFD and it would probably work will on lighting circuits supplied by a dimmer whereas many other clampmeters won't. A few other things in its favour are it's true RMS, it's got a high hold feature and you can switch off the auto power down so it can be left in a DB or panel overnight to record the maximum current event. Finally it was very cheap.

Here's the manual and data.
http://www.chauvin-arnoux.at/download/digiflex/ba_ma400d.pdf

Testmeter have it available on their website for 134 of you UK pounds before forum discount.

thanks marvo, ill buy it this month if i have missed out on the mft

(i haven't needed one yet cause we dont use rcd's day to day)

 

[Deleted member 9648]

Really?

I test the RCD to check its functionality, then the clamp to check the "back ground" leakage, then IR - unless its abundantly clear one specific circuit is to fault!

YES!! Really!
I've just seen so many jobs where a 'faulty' RCD has been changed only for the tripping to continue. I'm not knocking anyones approach just because it's different to mine,but one thing will never change....if I have a tripping RCD the first thing I will do is an IR test and eliminate that before any other tests. End of!

 

[telectrix]

YES!! Really!
I've just seen so many jobs where a 'faulty' RCD has been changed only for the tripping to continue. I'm not knocking anyones approach just because it's different to mine,but one thing will never change....if I have a tripping RCD the first thing I will do is an IR test and eliminate that before any other tests. End of!

NO, NO, NO !. that's the second thing. the first thing is to hit it with a hammer. :49:

 

[richard1972]

do you use IR test majority of time and only use ELCM on intermittent tripping ? or is it quicker to use ELCM on permanent tripped rcd sometimes ? i want to buy ELCM but trying to understand how often i will use versus how much to spend

anyone ?

 

[Deleted member 72666]

^^^^
Stop tormenting yourself , you'll never see this as a bad buy I guarantee it in fact you'll end up using it more than you think so go out and get yourself one you know it makes sense!

 

[Marvo]

anyone ?

I think your answers are already in this thread. The two methods of test are chalk and cheese really; IR is a dead test, ELCM is a live test. IR is measuring insulation values ELCM is measuring actual real-live leakage which is what the RCD is seeing. IR test uses a DC test signal so may not be an accurate reflection of leakage if there's appliances connected with internal surge arrestors. An ELCM can be used as a monitor over time whilst an appliance is running, an IR tester can't. An ELCM can monitor leakage across a live 3 phase supply, an IR tester can't. An global or single circuit ELCM test can often be made without interrupting the supply, an IR test can't.

There's also lots of advantages that an IR tester also has for certain tests but I'm sure you get my point which is that both testers have their place in your toolkit in my opinion although there are some people who maintain you can live without an ELCM if you have a megger tester and an RCD ramp tester. I'd concede you probably could live without one if you were stubborn as a mule and you're mind was made up but my argument would then be why risk making your life difficult when the cost of an ELCM is so low?

 

[Deleted member 9648]

I think your answers are already in this thread. The two methods of test are chalk and cheese really; IR is a dead test, ELCM is a live test. IR is measuring insulation values ELCM is measuring actual real-live leakage which is what the RCD is seeing. IR test uses a DC test signal so may not be an accurate reflection of leakage if there's appliances connected with internal surge arrestors. An ELCM can be used as a monitor over time whilst an appliance is running, an IR tester can't. An ELCM can monitor leakage across a live 3 phase supply, an IR tester can't. An global or single circuit ELCM test can often be made without interrupting the supply, an IR test can't.

There's also lots of advantages that an IR tester also has for certain tests but I'm sure you get my point which is that both testers have their place in your toolkit in my opinion although there are some people who maintain you can live without an ELCM if you have a megger tester and an RCD ramp tester. I'd concede you probably could live without one if you were stubborn as a mule and you're mind was made up but my argument would then be why risk making your life difficult when the cost of an ELCM is so low?

Lol....yes I'm as stubborn as a mule!
My first point here is that I've been fault finding RCD's for years quite alright thankyou very much without an ELCM,so they are hardly essential,useful I would concede and I should probably possess one,but essential no.
A second point is that from following these threads over the years it is apparent that many never even consider an IR test.I think thats a mistake. And I'll state again the numerous times I've gone to a replaced RCD still intermittently tripping and found a low IR.

 

[Marvo]

Lol....yes I'm as stubborn as a mule!

It was just a small dig

 

[richard1972]

I think your answers are already in this thread. The two methods of test are chalk and cheese really; IR is a dead test, ELCM is a live test. IR is measuring insulation values ELCM is measuring actual real-live leakage which is what the RCD is seeing. IR test uses a DC test signal so may not be an accurate reflection of leakage if there's appliances connected with internal surge arrestors. An ELCM can be used as a monitor over time whilst an appliance is running, an IR tester can't. An ELCM can monitor leakage across a live 3 phase supply, an IR tester can't. An global or single circuit ELCM test can often be made without interrupting the supply, an IR test can't.

There's also lots of advantages that an IR tester also has for certain tests but I'm sure you get my point which is that both testers have their place in your toolkit in my opinion although there are some people who maintain you can live without an ELCM if you have a megger tester and an RCD ramp tester. I'd concede you probably could live without one if you were stubborn as a mule and you're mind was made up but my argument would then be why risk making your life difficult when the cost of an ELCM is so low?

thanks marvo.

i understand they are different, and from reading the posts, it seems that on an intermittent trip scenario, they would be very useful. im just trying to understand when and how i/you would use ELCM and how it would speed up finding fault

on a permant fault rcd tripped, you can find fault using IR test ( how would/could a ELCM make things quicker )

sorry if im being particular, but im just trying to work out how much to spend versus how much would/could use

 

[shanky887614]

thanks marvo.

i understand they are different, and from reading the posts, it seems that on an intermittent trip scenario, they would be very useful. im just trying to understand when and how i/you would use ELCM and how it would speed up finding fault

on a permant fault rcd tripped, you can find fault using IR test ( how would/could a ELCM make things quicker )

sorry if im being particular, but im just trying to work out how much to spend versus how much would/could use

if you have got an intermitant fault it could be on say an element that only leaks enough when it gets upto temperature or on cheap electronics when its under load.
its one of those tools that most will only use once in a bluemoon but when in certain cases you will be glad you have it.

(i dont see the point in most people having them calibrated though)

 

[Octopus]

The "other" time the ECLM is useful, is when you are scoping a CU change - its useful to guage the leakage across the existing board!

 

[davesparks]

thanks marvo.

i understand they are different, and from reading the posts, it seems that on an intermittent trip scenario, they would be very useful. im just trying to understand when and how i/you would use ELCM and how it would speed up finding fault

on a permant fault rcd tripped, you can find fault using IR test ( how would/could a ELCM make things quicker )

sorry if im being particular, but im just trying to work out how much to spend versus how much would/could use

If the fault is permanent then an ELCM will be no use at all, the RCD won't stay on long enough to get a reading! This is when an IR test would be employed.
However an intermittent fault where tripping occurs at apparently random intervals will be easier to find with the help of an ELCM.

 

[Silly Sausage]

He doesn't need an earth leakage clamp...................

I think it shows your excellent fault finding skills myself.