Fault finding help

Cirrus · Aug 26, 2008

Ok chaps, a customer calls you saying he has a 'tripping problem' on his CU. Apparently it is totally random and no rhyme nor reason to it. No work done recently etc etc but the RCCB trips every now and then and the guy is worried as he is going on hols soon and naturally doesn't want fish to die etc should the power go off.
Now, where would YOU start? I reckon best way is to change RCCB for a new one and then go from there but what are your thoughts chaps?

wattsup · Aug 29, 2008

Does he live near a power station? sometimes crazy peaks, I've measured 270v next to ferrybridge, client always said lamps always blowing, now with rcd safety police on patrol it knocks all the friggin lot off when peak flow and a lamp 'pop's (well that bank)..the leccy company, errr what err not us. Oh yes it is. Now one rcd for shower, one rcd for kitchen ring. All other on cartridge fuses, no probs the lamps still pop but it don't knock the friggin lot off.

jonboy1 · Aug 29, 2008

If the RCD is a wylex I would change for another. There was a spate of dodgy RCD's from Wylex that tripped for no reason. Apparently from a supplier in China> Had a recurrent problem with this and I changed RCD to Hager. No problemo!

Cirrus · Sep 1, 2008

Well, been to the clients tonight and they had a 'sparky' fit a small adaptable box outside for and o/s light. No drip loop and no rubber glands used. Opened box up and 200 litres of water fell out. "Oops" said the client - "won't be using them anymore, would you like the job of putting it right??"

DIY SOS!!!

tony.towa · Sep 2, 2008

Well done Cirrus. Glad you found the fault. Was just about to suggest you recommend the customer to "the cook book" and modify one of the trout recipes for his fish!!!!

old dog · Sep 2, 2008

all of the above ir test all circuits get customer to isolate i circuit at a time this may take some time depending on what random tripping time scale is sort out a circuit non rcd
for fish tank fridge freezer get back to him/her after hols good luck intermittent faults
are the worsed kind
goodluck

madeinengland · May 20, 2009

you'll probably find that they've got an old fridge or fridge feezer and there is a fault on it which is gradually building up.so sometimes the fridge is fine and other days it is not.you'll probably find that you don't pick up the fault even on a pat test. when the thermostat kicks in and then the motor or whatever starts to cool the fridge back down it draws more current and therefore trips the rcd/rccb.change the fridge is the best way.

Spudnik · May 20, 2009

As this thread is over 8 months old, i would hope the problem is sorted now

8181piv · Aug 18, 2009

i have a problem with regular random RCD operation found this to be the under floor heating, this has been disconnected with the intenton of reconnecting on seperate RCD supply, circuits fed via split load CU with 80A 30mA RCD, RCD feeds kitchen ring, oven, microwave, garage and utility circuits, main switch suppling all lighting and first floor sockets. RCD has not operated for the last 3 days, but customer has just called to say it has tripped when a lamp blew in the kitchen, now as far as i am aware this should have know bearing on the RCD operation as it is is fed via main switch, can someone advise.