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dayrider3883

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I have a neutral to earth fault that trips my main switch RCD disconnected neutral to bathroom lights and trip is ok is neatral to earth a problem on TT systems
 
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1shortcircuit

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  • #3
Neutral to earth will create any RCD an issue as this is where it is doing it's job:thumbsup
 
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dayrider3883

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  • #4
yes but i have the live circuit beaker switched off to the bathroom
 
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dayrider3883

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  • #6
no i have the fan disconnected with the bathroom circuit breakes off the main switch operates until i disconnect the bathroom neutral at the cu
 
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1shortcircuit

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  • #7
no i have the fan disconnected with the bathroom circuit breakes off the main switch operates until i disconnect the bathroom neutral at the cu
Was this fault present before you started the work?
 
But I assume you have other circuits still live and switched on ...................think neutrals and think commoned up at the board ..........and now think why the RCD is still tripping
 
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dayrider3883

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  • #9
No Lightings been ion abuot 1 year 4 spot lights
 
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dayrider3883

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  • #10
Yes but with live off on lighting circuit i cant see how its nuetral can effect the other circuits
 
Line and neutral in a single phase installation ................................if you have a load (amps) going down the line they return on the neutral ......ok

You have a Ring final circuit with a load on it ..........so we flow down the Line and back through the neutral ....................still ok

You have a faulty light circuit which is tripping the RCD ..................isolating the breaker still trips the RCD, but when you disconnect the neutral it says in .................... still there

Now because your neutrals are commended at the board your getting the returns from your other circuits back to the neutral bar ...........remember the RFC. well when you connect your neutral from that light circuit into that bar .........you back feeding from the neutral bar into that light circuit, where there is a fault and causing the inbalance, that is causing the RCD to trip ......
 
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StuSpiers

  • Thread Starter Thread Starter
  • #12
Draw an RCD out.

then think how the circuits are connected.

Your RCD sounds like it is working perfectly.

You have A neutral to earth fault on your bathroom circuit, switching the mcb off does not isolate the bathroom neutral.

Neutral current from other circuits is flowing up the bathroom neutral towards the fault therefore causing an imbalance of phase - neutral currents.
 
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dayrider3883

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  • #13
but with the switch off to bathroom what is supplying the in balance
 
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1shortcircuit

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  • #15
I think this thread may be stepping on the toes of "Questionable Competence" so I am out as they say in the Den.

Good Luck, I hope you resolve the issue:thumbsup
 
Malcolm tells you in post 11 mate. Your lines go into the top end of your MCB, your neutrals go in the neutral bar. Turn off the MCB and line is isolated, the neutral is not as it is connected to all the other neutrals in the installation. Current flows from line through appliance then back down neutral. Obviously some of this is flowing down the neutral where the problem exists thus tripping the RCD.
 
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Amp David

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Mentor
Arms
Why do people insist on messing about in consumer units trying to fix things when they don't know what they're doing?
 

Amp David

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Mentor
Arms
The things that I find interesting is that with a tiny bit of testing/fault finding, you'd have the answer in not a very long time. Since it appears the OP has actually completed the 2391, then I am now beginning to worry a little.
 
Don't see any evidence of 2391 mate, I'd hope that someone with that would be able to figure out why the RCD is tripping. Maybe I expect too much though
I stand corrected, OP claims a 2391 pass in 2007 on another thread. Now I'm really scared
 
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1shortcircuit

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  • #22
OP claims a 2391 pass in 2007 on another thread. Now I'm really scared
After reading this thread I decided to take a look at previous posts by the OP and I'm sorry to say that I personally believe this to be a load of BS. I do not have 2392 or 2391 and I would put money on the fact that I could quickly identify and remedy the fault. I'm absolutely shocked to learn that someone with such a qualification (that requires a vast amount of knowledge and in the field experience) could be posting such amateur questions.

UNBELIEVABLE!
 
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Octopus

  • Thread Starter Thread Starter
  • #23
After reading this thread I decided to take a look at previous posts by the OP and I'm sorry to say that I personally believe this to be a load of BS. I do not have 2392 or 2391 and I would put money on the fact that I could quickly identify and remedy the fault. I'm absolutely shocked to learn that someone with such a qualification (that requires a vast amount of knowledge and in the field experience) could be posting such amateur questions.

UNBELIEVABLE!
Yes, its possible to pass the 2391 without hardly lifting up a tester, screwdriver or even getting your hands dirty!
 

DNS1

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Arms
I was putting off my 2391 for a while until I get a bit more experience, but if the OP has it without understanding the fundamentals of RCD protection then I'm going to enroll tomorrow...
 
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SPARTYKUS

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  • #25
I doubt he has the 2391.

If you need convincing of this, read this thread :thinking2:
 
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sedgy34

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  • #26
Yes but with live off on lighting circuit i cant see how its nuetral can effect the other circuits

mate get a sparky in diyers dont understand the theory of neutral earth faults but why should you need to when you can hire a sparky
 

plugsandsparks

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Arms
Esteemed
Easy way to demonstrate this. Find a house with upfront rcd, choose a circuit, switch said breaker off at board, open up a switch or socket or FSU on said circuit whatever (make sure the house is nicely loaded up with other stuff like tele, lights, immersion heater etc) - then with a pair of insulated pliers remove the neutral wire from the scoket or switch or fsu and touch it against the metal of the backbox or earth terminal ANNNDDD oh go and get a torch.....

This is standard operating procedure for any spark working on multiple ccts with rcd up front, i.e. trying to work on one circuit without tripping the rcd. LOL
 
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sparks1973

  • Thread Starter Thread Starter
  • #28
Easy way to demonstrate this. Find a house with upfront rcd, choose a circuit, switch said breaker off at board, open up a switch or socket or FSU on said circuit whatever (make sure the house is nicely loaded up with other stuff like tele, lights, immersion heater etc) - then with a pair of insulated pliers remove the neutral wire from the scoket or switch or fsu and touch it against the metal of the backbox or earth terminal ANNNDDD oh go and get a torch.....

This is standard operating procedure for any spark working on multiple ccts with rcd up front, i.e. trying to work on one circuit without tripping the rcd. LOL
beggers belief dunnit...lol..
 
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dayrider3883

  • Thread Starter Thread Starter
  • #31
found problem when removed one off the spotlight cable had melted together also found what looks like bite marks on cable could have been a mouse
 

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