Random Rcd Fault

[Steve3948]

Not necessarily. But at least it will narrow it down to one circuit!

From the testing done it does not seem to me that any one circuit is the issue but possibly accumlative over several, leakage tester would possibly give a better idea which circuits are the culprits.

 

[OnOff]

Haven't got loose neutral(s) somewhere? 

 

[MeFil]

I have seen similar faults on the past.

One turned out to be a capping nail through that nicked a live core of a T&e. Caused nuisance tripping when it rained.

And I have seen a neutral on an rcd ring circuit cross connected to the neutral on a non rcd lighting circuit. That also caused nuisance trips.

I would suggest doing an ir test on the installation as a whole and seeing what value you have. If all the appliance are testing out ok, then the earth leakage causing the rcd to trip must be coming from the wiring.

If that all test out fine then I'd be testing for continuity between the neutrals of all the circuits...see if you have a random cross connect somewhere.

 

[chris_k]

A bit of an update.

I left the installation with cir 4 on an rcbo as it seemed this was the circuit pushing the RCD to its limit. I asked the client to monitor any further tripping and i`ll give them a bell after the weekend.

Up till tonight there has been no tripping of either RCD or RCBO. Happy days!!

It must have been a cumulative leakage tipping the RCD over the edge. Even when the client plugs in his Tesla Roadster it doesnt trip (used to trip immediately) I should really drop by and do some more testing to find the real problem. At the moment im happy ive narrowed down the problem.

Be it luck or whatever its took 2 visits from British Gas home care thingy and 2 visits from other sparks then me to stop the tripping.

Happy Customer!

Thanks for your views and help.

 

[eleccourses]

that's not a solution

 

[Murdoch]

that's not a solution

Quite. Thats a bodge

 

[Steve3948]

so if you have 10 circuits and 4 circuits have small leakage most likely due to old appliances and accumlatively they total 20mA, what do you do, individual RCBO's would not present an issue.

 

[maddfridge]

hi there

you say the house is in the middle of no where and is a tncs system out of interest is the house an over head supply which has been pme by the dns ?

have had issues with this in the past due to a parallel earth problem 

i would check for old bonding if the house is old the old twisted wire stuff had a load of the stuff once removed problem was resolved 

hope that helped 

cheers mf