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!

 

[Darkwood]

Have you done a full dead circuit test while fully disconnecting the ring from the board or are your globally testing them, also was the main switch on when you found your N/E issue?

 

[chronyx]

As time was short I ended up looking for likely areas where a cable could have been damaged and I.R testing, but not the whole circuit yet. Found one that was very tightly packed against a stud, but it tested out OK and my eureka moment was lost.

Good point about the main switch, I see where you're going with that. It was on.

A 10pm reply is appreciated too!

 

[davesparks]

Disconnect the circuit, test it in a logical manner, find the fault, fix the fault, test, fill in the certificate, job done.
It's as simple as that!

And it might be an idea to not waste your time touching conductors to different neutral bars to see what happens, it won't achieve much and makes you sound like your not a competent electrician.

 

[chronyx]

Can't argue with that. It had been a long day.

 

[davesparks]

Can't argue with that. It had been a long day.

That all depends on your definition of a long day really

 

[DPG]

That all depends on your definition of a long day really

"Longer than a short one". Daz

 

[Integrity]

I've had similar recently, and it took me hours to sort, I eventually fixed all 7 seperate issues. But Davesparks and Darkwwod are right, follow your dead testing fully and in the prescribed order and you will get there. You may find like me, that there are multiple faults and as you find and fix one, you start back at the begining at work your way through. There is little point in going for best guess when you already have the tools, be methodical and logical and you will prevail.

 

[LankyWill]

start dropping sockets shag

 

[davesparks]

start dropping sockets shag

Do what?

 

[DPG]

Do what?

He means "commence removing sockets dear". Daz

 

[davesparks]

He means "commence removing sockets dear". Daz

I got that, I was more interested in why a random removal of sockets would be a sensible approach?

 

[LankyWill]

I got that, I was more interested in why a random removal of sockets would be a sensible approach?

no end to end results usually happens with a loose connection David, so as to drop sockets you could find the loose neutral....

 

[davesparks]

no end to end results usually happens with a loose connection David, so as to drop sockets you could find the loose neutral....

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.

 

[Octopus]

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

 

[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?????

 

[Deleted member 26818]

Where's the stats for top thanked poster, and how is Dave the most thanked?

 

[GMES]

Where's the stats for top thanked poster, and how is Dave the most thanked?

It's at the bottom of the home page and if you click on it it shows all the stats like top thread starter in the last 60 days, top pster, most thanked etc.

I'm off to work now so you're on your own

 

[Leesparkykent]

 

[chronyx]

Neutral to earth reversed in a choc box hidden in a stud wall.

The homeowner had done it themselves a few years ago. Got the 4 inch hole saw out, access hole cut, cables sorted, job jobbed.

 

[Paul.M]

@ GMES. You are not in the top ten for "Thanks"!!! You should be after all the hard work you put into this place.

Just a hint to members GMES puts a lot of hours into the forum (same as all of the staff) and he should be in the top ten. Here you go mate, I've just put a Thanks on your last 3 posts to push you up the list (and me off it lol). Luv you Silver-back, my turn for the breakfast next time.