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Rcd tripping

3425 Views 9 Replies 8 Participants Last post by  bennysecond
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
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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
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
 
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