Grimysparkette needs help with RCBO tripping

[grimysparks80]

Hi guys. Had a callout a couple of weeks ago. 32aRCBO trips every 6 to 7 days. After doing insulation resistance, R1 R2,earth loop ect, and not finding anything i decided it was faulty and replaced.

Its still tripping out. The customer has marked it on the calendar every time its gone. Usually goes on the thursday and a couple of times its held on untill friday. Always lasts 6 to 7 days after being reset.

Any Ideas?

Im posting this as Grimysparkette......

.... So am expecting at least 10 pages of answers from helpful sparks who`ll do anything for a lady.

And Widdler forfeits all bragging rights if he makes more than one post.lol

 

[jeremy]

What is the rcbo supplying? Sockets?

 

[grimysparks80]

Yep. Its a Ring circuit in a bungalow. Old couple so nothing much on it. Just the usual household appliances

 

[johnboy6083]

is there anything specific that they do on a thursday ect? for example is it takeaway night, and they use a microwave to heat it up? is there an sort of pond or swimming pool, that may have as filet on a 7 day timer? heating system?

 

[Lighthouse Phil]

Any timers on the circuit supplied from the RCBO?

 

[grimysparks80]

No timers. Asked all the usual qustions. It doesent go at the same time every thursday. Sometimes morning sometimes evening. twice on the calendar its waited till friday to trip. Generally seems to take 6 - 7 days to trip after being reset.

 

[telectrix]

ramp test with loads connected. there may be cumulative leakage.

 

[jeremy]

How many socket circuits are there? Would it be possible to supply equipment from another circuit to see if the rcbo still trips with no load? That would (probably) clear the appliances. Is this the only rcbo/ rcd on the db?

 

[Johnny-G]

Hi, A/S/L?

 

[Des 56]

Does it rain only on a Thursday in Lincoln

If it was on that circuit,my own feeling would be something amiss with the central heating system
The freezer/fridge/washer,anything motor driven

Have the appliances been tested ?
An insulation resistance test with those appliances in circuit
Are the sockets double pole and the appliances left plugged in when not in use ? if so get them in the habbit of removing them

A fault on a circuit or appliance that does the buisness continually is always easy, but intermittent tripping is probably the worst pain in the neck faults to pin down,good luck
The customer usually doesn't appreciate this fact

 

[grimysparks80]

Thanks for the suggestions.

Just the one socket circuit so no chance of plugging stuff in elswhere. Not really practicle to set up anything temporary as its taking so long to trip.

The cooker is also on an rcbo. other circuit are on breakers.

Not heard the term A/S/L before. Can anyone explain it?

It usually rains in Lincoln on thursdays Des but never on fridays, and the jobs in mablethorpe so no help there.

Im thinking it must be one or more of the appliances as all the tests ive done so far have been focused on the circuit with everything unplugged.

Cheers Tel. Will be goung back at some point to do ramp test and look at appliances.
The customers a friend and doesnt want anything doing at any expense if its not dangerous. Its more for my own curiosity (and a few beers) at this point.

 

[dasrik]

Intermittent faults are a real pain in the backside - you can only fix something that's broke!

As mentioned before look for something they do every Thursday (or wed night) like the washing etc, if possible get them to unplug all non essential appliances on wednesday night to see if this has any affect, you may be able to pin point an appliance or rule them out this way.

Also what time of day does it mainly go?

can't think of anything else right now

 

[JD6400]

Could it be from a neighbouring property , had this once on a farm that ended up being a total rewire i am convinced to this day that the neighbouring farm was the cause .
It is bloody rare but have heard of it a couple of times ?
Got Friends up this week and of to the beach at Sutton on Sea tomorrow morn , will take me spotting glasses and try to see you !

 

[grimysparks80]

Ill be the guy in the cowboy hat on the broken down nag.

I heard about one where there was earth leakage from next doors earth rod, but this is tncs.

 

[gnselectricals]

Have u tried replacing the RCBO to see if it's faulty ?


Sent from my iPhone using Tapatalk

 

[malcolmsanford]

Check your Zs values and replace the RCBO for temp with a MCB and monitor that.

If the MCB doesn't trip then as Tel said do a ramp test though you have said you have replaced the RCBO, and also check to see if there are any High Protective Conductor currents on the circuit.

 

[Paul.M]

Is Thursdays bath night in this house hold? Do they have an immersion heater and the element is on the way out?

 

[richy3333]

I have no idea what the answer is, but having seen your photo, you're gorgeous Are you free Friday night for a donkey ride along the front at Mabbles'

On 2nd thought, isn't that the cause of the fault: Mabblethorpe?

 

[BillyTheSparks]

My parents had a similar problem once. The main switch 30ma RCD would trip for no reason whatsoever, and it would be an iregular event. This happened until they had a power cut and the suppliers cable (to their property) had broken in the ground, once repaired no problems at all.

I know this probably wont help too much, but could it be an external influence insted of an internal fault?

 

[BlueToBits]

I know it's unlikely but FWIW; A few years ago I found a self defrosting fridge that worked by sending water from the ice build-up onto an open tray sitting on top of the warm compressor so that the water would evaporate. Because the fridge door seals had gone, the ice build up was excessive and the tray overflowed and ran along a cable into a compressor connector box. This would cycle each time the fridge decided it was time for a defrost.