# Rcd tripping



## brianearnsh (Dec 15, 2013)

Hi guys
I've recently competed an installation on a large domestic property

I've now found that one of the Rcds is tripping every 2 or 3 days 
I've isolated a ring main circuit and the rcd is fine.
I've carried out insulation test on circuit L-N L-E N-e all clear
But when I test between cpc of the disconnected circuit and neutral bar at cu I get a reading of 4-5MOhm on both outgoing legs
I've split the ring into to 2 radials,but still get this reading on both halves 
I've also got 50V between disconnected earth and neutral bar
Any ideas guys
Cheers brian


----------



## ibuzzard (Dec 28, 2008)

Hi, Brian. You might want to ask this question in the U.K. Forum of ET. We don't use RCD mains here, or ring circuits, like you guys do. Good luck.


----------



## Dennis Alwon (May 9, 2009)

I moved it to the UK forum


----------



## WarrenG (Apr 25, 2012)

brianearnsh said:


> Hi guys
> I've recently competed an installation on a large domestic property
> 
> I've now found that one of the Rcds is tripping every 2 or 3 days
> ...


Brian could you give some more info?

i.e 

Have you totally rewired the property or is the work you carried out an additional installation?

Have you determined that the ring final circuit is the only circuit causing the nuisance tripping?

Have you ramp tested the RCD? If so, what level is it at? 

Generally a 30mA will be around the 22-26mA mark.

Have you tested for earth leakage of the connected loads?

Remember Fridge freezers, ovens, electronic equipment with mains input filters, grills and immersion heaters etc all can have typical high leakages.

Have you checked for faulty appliances? A faulty appliance could be present in use with a high leakage and still within the RCD limit.

As soon as a fridge stat drops and the motor kicks in this could send the RCD level overboard. 

Are your neutrals where they should be and in the correct bus bar for a split load board? 

If your disconnecting your neutrals at the CU and are getting a voltage, then its clear there is an interconnection somewhere between the CU and your circuit(s).

Have you tested for a clear seperation of circuits? Especially if the work was additional.

Sounds to me you need to investigate further. Don't forget things like outside lights (often spurred from the ring final) or hidden equipment in loft spaces.

Good luck. 

WarrenG


----------



## septiclecky (Oct 17, 2008)

ibuzzard said:


> Hi, Brian. You might want to ask this question in the U.K. Forum of ET. *We don't use RCD mains here*, or ring circuits, like you guys do. Good luck.


You do you call them GFI in the USA


----------



## dmxtothemax (Jun 15, 2010)

Tell us more about this 50v your measuring between earth and neutral?
This should not be !
Exactly where are you measuring this ?
And with what are you measurimg ?


----------



## 8V71 (Dec 23, 2011)

dmxtothemax said:


> Tell us more about this 50v your measuring between earth and neutral?
> This should not be !
> Exactly where are you measuring this ?
> And with what are you measurimg ?



Sounds like someone is bored. :whistling2:


*brianearnsh *

*Junior Member*

Last Activity: 12-16-2013 07:42 AM


----------



## ibuzzard (Dec 28, 2008)

dmxtothemax said:


> Tell us more about this 50v your measuring between earth and neutral?
> This should not be !
> Exactly where are you measuring this ?
> And with what are you measurimg ?


Did you just awake from a three-month nap down there?


----------



## dmxtothemax (Jun 15, 2010)

ibuzzard said:


> Did you just awake from a three-month nap down there?


 
Haven't you heard of island time ?

Or T I time ?

Where in no hurry here.


----------



## bennysecond (Jan 18, 2013)

hmm...inducted voltage


----------

