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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

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  • #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
 
1

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
 
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