... and, as I recently wrote, no clamp meter would be any use if (as would commonly be the case in the heating context) the earth leakage was directly to 'earthed metal', rather than through CPC.
Kind Regards, John
RCBO tripping.
- Thread starter Burnerman
- Start date
Kind Regards, John
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There seems to be some confusion.
An Insulation tester will only tell you if there are any permanent faults on the dead circuit - if not, that's it.
An earth-leakage meter, the clamp of which is placed around the live Line and Neutral conductors (not any of the CPCs - it is itself really a live RCD) will instantly tell you if there is NO leakage, in which case it might be laborious to determine the cause by operating the various stages of the equipment and viewing the readings.
OR
Either meter might tell you that there is a permanent leakage of, say ~22mA, (although I would say the ELCM will be more accurate) in which case it will take very little more to trip the RCD. This 22mA leakage can then be found and removed/repaired and then all should be well.
An Insulation tester will only tell you if there are any permanent faults on the dead circuit - if not, that's it.
An earth-leakage meter, the clamp of which is placed around the live Line and Neutral conductors (not any of the CPCs - it is itself really a live RCD) will instantly tell you if there is NO leakage, in which case it might be laborious to determine the cause by operating the various stages of the equipment and viewing the readings.
OR
Either meter might tell you that there is a permanent leakage of, say ~22mA, (although I would say the ELCM will be more accurate) in which case it will take very little more to trip the RCD. This 22mA leakage can then be found and removed/repaired and then all should be well.
True. I must admit that (probably because I have never owned or used a "mA" clamp meter, I'd overlooked the ('obvious') approach of clamping it around L+N. Apologies for that oversight.
Yes - or, more precisely, "if there is NO permanent leakage".
As with any fault finding, no matter what means of testing one is adopting, the potential nightmare arises if the fault (at least, the majority of the fault current which is resulting the the tripping) is intermittent in its existence.
Kind Regards, John
Just around those two wires the L and N leaving out the E, would work - assuming he could get his hands on a suitably sensitive instrument, which seems highly unlikely. Hence why I have twice suggested that a common or garden insulation tester is the way forward. His electrician guy should certainly have readily one to hand and it might prove quick way forward..
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Of course it would work; that's how it is done.
As I said, once I realised my oversight, it was 'obvious' that such was the thing to do...
Although, as I said, I have never owned, nor even used, a "mA clamp meter", they have been widely available (and not necessarily as expensive as one might expect - although some {e.g. Fluke} are!) for years.
It might, but as i have also 'suggested' (probably more than 'twice'
) IR testing would only be useful if most of the earth leakage were present 'permanently', with just a little extra leakage from something added to it occasionally, to take the RCBO ('intermittently') over its trip threshold.However, as I keep saying, if all (or most) of the leakage which causes the trips is, itself, 'intermittent' (which I suspect is quite probably the case), then IR testing would be of no help (unless one were exceptionally 'lucky'!!).
Kind Regards, John
Once again, I appreciate your comments gents and thanks for sharing them with me.
I don't feel I can trouble the electrician to hang around and test the burner etc just now - he is rushed off his feet anyway.
I think I'll rewire the boiler internals just in case the original cables are starting to fail due to the considerable heat that's within the boiler housing and take it from there.
Cheers
John
I don't feel I can trouble the electrician to hang around and test the burner etc just now - he is rushed off his feet anyway.
I think I'll rewire the boiler internals just in case the original cables are starting to fail due to the considerable heat that's within the boiler housing and take it from there.
Cheers
John
This is at least the second time you've mentioned the burner (which you may soon be replacing) but, in the context of this discussion (and although I agree that 'anything is possible'), I would think that it's very unlikley to be the cause of your RCBO trips.
There's nothing to be lost by doing that (if its done properly), but unless the wiring show signs of thermal damage, I again think it unlikley that that would solve your problem.
Anyway, good luck!
Kind Regards, John
I wouldn't be as sure - I'm not familiar with them nor what parts they might include.
I’m only going for the burner because my system is very basic with a room stat controlling the circulating pump.....the boiler has only a knackered time clock and off/on switch.
The burner consists of a 70w motor, control box and transformer igniter plus an oil supply solenoid so maybe there’s potential issues to look at, at least.
I’m able to swap the burner over with my spare in an hour.
If the boiler is unplugged, the supply remains on.
Thanks!
John
I’m only going for the burner because my system is very basic with a room stat controlling the circulating pump.....the boiler has only a knackered time clock and off/on switch.
The burner consists of a 70w motor, control box and transformer igniter plus an oil supply solenoid so maybe there’s potential issues to look at, at least.
I’m able to swap the burner over with my spare in an hour.
If the boiler is unplugged, the supply remains on.
Thanks!
John
With so many likely parts to suffer earth leakage, classed as 'the burner', the burner would be my prime suspect without any doubt and that despite John's opinion to the contrary.
Oh, I thought you meant literally just the 'burner' - what you are now talking about offers a significant amount of scope for electrical issues - so it will be interesting to hear what happens if/when you replace it.
Kind Regards, John
As you will presumably understand, my "opinion to the contrary" was expressed when I was assuming that "the burner" was just the burner (as it would be in my ancient gas boiler). We have now been told that "the burner" includes most of the electrical parts of the boiler, and so my opinion has obviously changed!
Kind Regards, John
https://www.google.com/search?q=Int...A&biw=1366&bih=657&dpr=1#imgrc=u9Vboeydufe0HM
The burner in question!
Basically you see the motor and cap bottom left, control box top left, igniter transformer top right and the oil pump with solenoid bottom right.
Well obsolete now but parts are available and it's simple enough.
John
The burner in question!
Basically you see the motor and cap bottom left, control box top left, igniter transformer top right and the oil pump with solenoid bottom right.
Well obsolete now but parts are available and it's simple enough.
John
I hope to be back living in the house in early February so it's on hold until then.
Thanks for the interest!
John
Thanks for the interest!
John
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