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My ELECSA assessor, told me to test at a socket or light even on a DB change where you might not be 100% certain of having everyting unplugged or disconnected.

I couldnt give a rats --- what your assessor says lol.
And if all the mcbs are turned off it doesnt matter whats plugged in or not ???

:41:
 
I made the suggestion about equipment perhaps being the problem because,I trust Mark has carried out all the usual tests we would normally do,he has happened upon an unusual problem that requires an unusual cause

I made the reference to the no trip test of a loop tester to give comparison to what I was dreaming about

Dreaming,because I have no technical know how whatsoever, regards the intricacies or the workings of the rcd tester

I did however find this bit of information from a study into the effects

DC in Residual Current Devices
The widespread use of semi-conductor
devices in domestic, commercial and industrial equipment may result in the
flow of non-sinusoidal earth fault currents in the event of equipment insulation
failure. This can occur in certain circumstances where the waveform may be
rectified or chopped and these waveforms are said to contain a pulsating d.c.
component which may desensitise a standard Type AC RCD.

The above is somewhere along the lines of what I was thinking,it may be utter bullcarp and the problem will likely be standard, but its certainly an unusual cause


Some of the equipoment listed includes Phone chargers invertors,transformers etc
 
I made the suggestion about equipment perhaps being the problem because,I trust Mark has carried out all the usual tests we would normally do,he has happened upon an unusual problem that requires an unusual cause

I made the reference to the no trip test of a loop tester to give comparison to what I was dreaming about

Dreaming,because I have no technical know how whatsoever, regards the intricacies or the workings of the rcd tester

I did however find this bit of information from a study into the effects

DC in Residual Current Devices
The widespread use of semi-conductor
devices in domestic, commercial and industrial equipment may result in the
flow of non-sinusoidal earth fault currents in the event of equipment insulation
failure. This can occur in certain circumstances where the waveform may be
rectified or chopped and these waveforms are said to contain a pulsating d.c.
component which may desensitise a standard Type AC RCD.

The above is somewhere along the lines of what I was thinking,it may be utter bullcarp and the problem will likely be standard, but its certainly an unusual cause


Some of the equipoment listed includes Phone chargers invertors,transformers etc
hey no probs Des...i wasn`t having a go mate....it was just a bit of info i picked up some time ago about the old robin D-loc...thats all mate...
 
The OSG does advise testing as near as practicable to it's point of installation, and load supplied should be disconnected, but struggling to find that in the BGB
J
 
just to clarify as of now the board has 4 circuits on one rcd and these all test and behave normaly

3 circuits on the other rcd and they also test and behave normally

the problem circuit is just on mcb at mo but would effect either rcd if connected

have just had text to say nothing has tripped since i left at 1pm and on the old board it was going upto 10 times a day

so i am wondering if i have a transformer or something that tested ok cold after cu change but is stopping rcd tripping and also when it gets hot causes insulation fault remember l-e 299 n-e 100
 
The OSG does advise testing as near as practicable to it's point of installation, and load supplied should be disconnected, but struggling to find that in the BGB
J

It should be in GN3 , gives more detail on the nuts and bolts of testing.
 
11.1 osg p 106...so yes..i was wrong Biff on the testing too close thing...although some devices (MEMs) dont like it...
 
I remember going to a job a collegue had been to..... Rcd main switch not tripping so he ordered a new one and i went to fit it on his day off.
When i went to test it, wouldnt trip either so i did my tests and found a low resistance fault between Neutral and earth which turned out to be a trapped neutral in the fused spur. So sorted that and then checked both rcds and both were fine.
Just an idea
 

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