Split load RCD woes

[chronyx]

The usual C.U. change problem.

All circuits working except one (Ostensibly a ring circuit, once upon a time. It 'end-to-end's at the board) which seems to have a neutral to earth fault.

I was methodical so I don't believe any neutral conductors were misplaced, but even putting the two neutral conductors concerned into the small pre-RCD neutral bar that the RCD tails go to, resulted in an RCD trip as soon as the circuit was loaded, although not from merely touching them on the bar as below.

There's no continuity between either of the Neutral conductors and the 2 split load neutral bars, yet touch one of them onto either neutral bar and the associated RCD will trip.

Did as much investigation as possible after C.U. change and changeover switch install for a small back up generator.

In my roundabout way I'm just wondering if anyone has seen this before or has any tips. The circuit has been modified over the years so I can't really vouch for its condition. Just thought it was worth asking the hive mind.

One other question - would removing the tails from the RCD neutral bars so that they are electrically separate, then checking for continuity help identify a misplaced neutral? I assume no continuity would be desired.

There's a PayPal drink on offer to anyone that gives a winning answer!

Cheers!

 

[LankyWill]

And a logical testing process will find it a damned sight faster and without making you look like you are just guessing at the fault in the eyes of the customer.

Top marks on being as condescending as ever david, If you split and then half and half a ring you will find the fault in no time, how are you going to find an open ring without dropping sockets? Speaking from experience it should only take 30-45mins to find with this technique. And as far as looking like your guessing, the customer knows nothing of the practices of an electrician so that comment is redundant.

 

[davesparks]

Top marks on being as condescending as ever david, If you split and then half and half a ring you will find the fault in no time, how are you going to find an open ring without dropping sockets? Speaking from experience it should only take 30-45mins to find with this technique. And as far as looking like your guessing, the customer knows nothing of the practices of an electrician so that comment is redundant.

Simple, short two conductors together at the CU, then test resistance at each socket (without removing it) and the readings will gradually increase towards the break and will be highest at the last socket each side of the break. So then you should only need to remove one or two sockets closest to the break.

 

[Octopus]

or: try a Zs at all the sockets and write down the readings, if you get 2 close together and the readings are quite different, start looking there!

 

[NDG Elecs]

half, then half, then half - should sort it quite quickly!

No no no Murdoch..... It's half then quarter then eighth!! :teeth_smile:

 

[GMES]

Top marks on being as condescending as ever david, If you split and then half and half a ring you will find the fault in no time, how are you going to find an open ring without dropping sockets? Speaking from experience it should only take 30-45mins to find with this technique. And as far as looking like your guessing, the customer knows nothing of the practices of an electrician so that comment is redundant.

To be fair Dave Helps a lot of members out with his knowledge and he knows his onions, yes his replies can sometimes appear a bit sharp but he always comes up with the goods.
If anyone takes a look at the top thanked,liked,poster, thread starters section you can clearly see that he is actually the top poster and also most thanked which for me is the important one because it proves he helps out a lot on the forum.
Just saying :wink_smile:

 

[sparksburnout]

I think Daves great he makes me laugh, is obviously a fantastic electrician, and just seems to shrug off any criticism without resort to personalities. It always fascinates me on how people would be if you met them, they very often are nothing like, I bet Daves a bit of a Dr Spock.

 

[telectrix]

second that comment. dave is very kbnowledgeable and helpful. so why does he drive a land rover?

 

[GMES]

I think Daves great he makes me laugh, is obviously a fantastic electrician, and just seems to shrug off any criticism without resort to personalities. It always fascinates me on how people would be if you met them, they very often are nothing like, I bet Daves a bit of a Dr Spock.

I just hope that's not cockney slang for something else. :smilielol5:

 

[telectrix]

dr. spock or mr. spock. ?

 

[sparksburnout]

I just hope that's not cockney slang for something else. :smilielol5:

Oeer I never thought of that, no it wasn't. but it might be used down in that neck of the woods eh? "That blokes a bit of a Dr Spock", very good.

 

[sparksburnout]

dr. spock or mr. spock. ?

Dunno can't remember. Anyway what about this Oven did anyone come up with a definite answer or are we sticking to a bit of 6 mil on a 32?

 

[LankyWill]

christ sounds like a circle jerk to me

 

[sparksburnout]

christ sounds like a circle jerk to me

Would you care to elaborate, we are all proper blokes up here.

 

[Deleted member 26818]

To be fair Dave Helps a lot of members out with his knowledge and he knows his onions, yes his replies can sometimes appear a bit sharp but he always comes up with the goods.
If anyone takes a look at the top thanked,liked,poster, thread starters section you can clearly see that he is actually the top poster and also most thanked which for me is the important one because it proves he helps out a lot on the forum.
Just saying :wink_smile:

???​...

 

[GMES]

???​...

????? What?????