rcd tripping

[matt12321]

ive got an rcd that keeps tripping on a split load board. circuits 3 ring mains, 3 lighting circuits and 2 boilers. insulation tests come back greater than 1M on all circuits, what else could it be, faulty appliance, rcd? what else could i look for

 

[GLENNSPARK]

either a faulty appliance or one (or more) of the neutrals are in the wrong neutral bars......could be a loose connection n all.....

 

[Octopus]

How long has the board been installed?

 

[GLENNSPARK]

ramp test the RCD....that will provide you with the level of fault current that the RCD actually trips at.....

 

[GLENNSPARK]

does this happen either....

a) when walking around the house....such as in the hallway?
b)when the boiler starts up?
c)after having a shower?

 

[GLENNSPARK]

has there been any work carried out at this property recently?

 

[matt12321]

about 7 years the board has been in. there are a fair few appliances in the house to determine, which it could be. ill try the rcd thanks.

 

[matt12321]

no work carried out recently, happened late last night and about 5 in the morning and about the same time a week earlier

 

[GLENNSPARK]

why not try isolating all final circuits at the C/U....then reset the RCD.....make sure that all connected loads on final circuits are on....then reinstate supply on each circuit in turn....until the rcd lets go......that will give you a start......oh and by the way...did you test strappers for 2 way lighting in BOTH directions when conducting an IR test?....

 

[matt12321]

thats the first thing i tried thanks glennnspark and yeh strappers tested. intermittent fault as all circuits turned back on individually and no individual circuit trips the rcd, it will trip at random times

 

[Octopus]

Sounds like a ramp test is in order.

Good luck and do let us know what you find.

 

[GLENNSPARK]

you say random times....but is this fairly regular though.....like something timed perhaps?....

 

[matt12321]

yeh will do thanks for the added advice

 

[Octopus]

yeh will do thanks for the added advice

You can use the "thanks" button

 

[Edd]

insulation tests come back greater than 1M on all circuits,

If I were getting multible circuits with reading around 1M or only slightly greater then I would be concerned. 2 circuits at 1M drops that too half straight away.. and with that nuesance tripping begins...
you say split load. If you cant narrow it down with testing I would be tempted to jump one circuit across and leave it a few days and see if it continues.. keep doing that till the circuit that trips has been swoped and the tripping stops... a cheat way out and takes time, but will help narrow it down

edit to say I dont mean leave it on the non rcd side forever just use that to find the fault