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B----r :| I knew that the phase issue would have got me in the end. Should have gone with my original thought about it which I immediately dismissed/retracted. Theres no substitute for sketching things out is there! But I still think there is still an open issue with TN-S/TT in a no load...

I don't think so. I think they will balance. keep in mind that the N-E 5Volts (and the subsequent 5mA that you mention) is not from the phase. It is from the Neutral via the sub-transformer so it passes through the Neutral side of the toroid (to earth) just as the phase current (5mA that you...

Yes I think it is. But that is not what I was trying to describe. Admittedly I could have described it better but my thoughts on it were evolving at the same time. What I am saying is that on a TN-S or TT supply the small N-E current that could exist can slightly modify the trip threshold...

I think it is an excellent idea John. As we have discussed in the past there is great confusion/disinformation (amongst electricians as well) about what RCDs do and do not do. I think what you have written already plus the discussions that have taken place in this thread just about covers it as...

Exactly, it will depend upon the circumstances you describe above. But what is interesting is that I have only started thinking about this in the past two days since this thread. I have never actually seen the scenario I described in the field (or perhaps not noticed it) I think I'm going to...

8)

We are only using the terms L, E, N etc for the sake of clarity. I see your point in terms of what is essentially a voltage divider analogy but my scenario is different (though as I accept I may be wrong) What I described is a current actually flowing "out of" the Neutral output of an RCD...

I completely understand why you are asking about testers and that is the right thing to do. My point is that you have only just completed your course, you don't yet have a tester. That is clear evidence that you don't have enough test experience. It's not just test experience anyway, with C&G...

But are you sure it won't? because that is the source of my confusion, it's just taken me a while to get there :roll: If there is a 5V PD between N and E from the supply (TN-S system) as I described why won't the current flow between N and E? Again, I'm not saying that I am right but it...

Correct, we are not talking highly inductive circuits here, the current will rise as fast as the resistance drops. If a human body completes a circuit between L and E then the maximum current will flow almost instantaneously. As you say in these circumstances no later then quarter of a cycle.

I'm sorry I am going to sound rude but I don't actually mean to be rude. You may feel comfortable in doing domestic electrics but that is completely different to selling your services to clients who expect an experienced expert. I both applaud and support anyone who wants to improve themselves...

Yes that is all true and that I understand, where there is a load current between L & N then say placing a resistor (to cause a 30mA current) between the output of N to E will cause N to be less than L by 30mA ------ but that is under load conditions. My thoughts (and I am still sure I am...

No, I'm familiar with those scenarios. I think I need to sleep on this one which usually works. I often wake up in the middle of the night in a moment of complete clarity. At this particular moment "wrong" has got me in a headlock :lol:

You are right. I am literally committing my confused thoughts to writing as I think of them. As soon I had hit submit I realised I was wrong on that. But I am still thinking about this N-E current. It is still not that clear to me.

It does and thank you but there is something about the no load situation I described which is confusing me to the point where I can't quite think through the logic clearly. One of those situations where I feel sure that I am wrong but I'm wrestling with wrong and it's got me in a Boston crab...

EDIT, dam - they would be 180 deg out of phase which I had not initially considered. Argh