Main fusebox problem

[stebrookfield]

Hi All,
In my home my mains fusebox trips on the RCD at 7.15am every morning. I have tested the system and found no obvious fault including electrical items that may require updates at a certain time etc. I have also PAT tested all electrical items.

Does anyone have any suggestions on what the problem could be?


Thanks for any help.
Ste

 

[alli]

As it is a very precise time, it sounds like something that is on a timer, maybe a immersion heater? Or similar.

 

[stebrookfield]

Thanks for the quick reply. There is no timer or immersion heaters. I also should have mentioned it is only the RCD that is tripping and not a particular breaker.

 

[Silly Sausage]

Thanks for the quick reply. There is no timer or immersion heaters. I also should have mentioned it is only the RCD that is tripping and not a particular breaker.

For each circuit that you have that is supplied from the RCD, each morning, say 7am, switch off the MCB and see if the RCD trips. That should help narrow the problem down to an individual circuit at least.

 

[alli]

As Archy Styrigg suggests. Also try and note all the appliances that are on at the same time in the morning e.g. washing machine, tumble dryer, electric shower, kettle computers etc. etc. Certain electrical equipment leak a little current to earth. Computers can leak upto 3.5mA. It sounds like there is a combination of electrical items on that are causing nuisance tripping.

Your RCD should be rated at 30mA so if you have a house full of electronic equipment it wouldn't take long to reach a point where nuisance tripping will occur. Also even though the RCD is rated at 30mA it may trip at a lower rate, if you have access to a RCD tester you may want to see at what point it trips.

 

[stebrookfield]

Cheers guys I'll give that a try.

 

[telectrix]

i'd go for the central heating boiler. does that kick in around that time?

edit: will the RCD reset immediately after tripping, and then stay in?

edit #2: is that time when somebody gets up and walks across the landing-- could be an intermittent fault under the floor, possible nail/screw, foot pressure triggering fault?

 

[lmdawson]

If the problem is nuisance tripping then I would suggest trying "high integrity" connections throughout the installation to discipate and earth leakage current, ie having two seperate connections for the earth in the back of sockets etc etc

Hope this helps mate...

 

[Simlec]

If the problem is nuisance tripping then I would suggest trying "high integrity" connections throughout the installation to discipate and earth leakage current, ie having two seperate connections for the earth in the back of sockets etc etc

Hope this helps mate...

Not sure how that would help !?!

My money is on heating system

 

[mogga]

5p says heating or Teles trapped cable

 

[c.boy]

Do you have an American type fridge freezer?? Or one that makes ice?? Came across a few that cause this problem even a normal fridge freezer can do this 2!! i would switch it off tonight and am pretty sure that this is the cause!!!

 

[telectrix]

Do you have an American type fridge freezer?? Or one that makes ice?? Came across a few that cause this problem even a normal fridge freezer can do this 2!! i would switch it off tonight and am pretty sure that this is the cause!!!

can't see the freezer kicking in at same time each morning, unless it's the auto defrost programmed for that time.

 

[c.boy]

Why not??? Most are designed to auto defrost 4 times every 24 hours!! dont know about you but a dont sit and time my freezer?as for the heating 10p it aint!! and the pressure fault is no way!!!! you would surely walk back to your bed the same way you get out??

 

[Big n Daft]

People that say "main fusebox", then mess, frighten the sh!te out of me.

 

[topquark]

Why not??? Most are designed to auto defrost 4 times every 24 hours!! dont know about you but a dont sit and time my freezer?as for the heating 10p it aint!! and the pressure fault is no way!!!! you would surely walk back to your bed the same way you get out??

Using that logic it would be tripping 4 times in a day, not just at 7:15am .... unless it's accumulated leakage with something else on the same schedule

 

[telectrix]

Why not??? Most are designed to auto defrost 4 times every 24 hours!! dont know about you but a dont sit and time my freezer?as for the heating 10p it aint!! and the pressure fault is no way!!!! you would surely walk back to your bed the same way you get out??

not necessarily. i might go from bedroom to bog, then down the stairs. and even walking back the same way might not tread in the same places. and i've known freezers defrost timing to be once a week, so the op's could be once every 24 hours.

 

[white armour]

Had a similar problem a while back; customer called saying that RCD had tripped every morning when she got up for work. After asking whether any electrical work, sockets or switches changed etc had been done recently she explained she had purchased an American style fridge/freezer (bells & whistles number), coincidentally that's when the problem started.

As board was 16th edition type and located in cupboard next to kitchen rigged up a surface mounted socket on the unprotected side for the appliance to be plugged into temporarily. Hey presto no more tripping RCD, customer phoned manufacturer and appliance was changed for a unit that did not trip RCD.

Hope that helps.

Regards wa

 

[claire_r]

Anyone have a shower before work? Seal perished around tray and a drip of water getting into a fitting or jb? Just another thought?!

 

[stebrookfield]

Had a similar problem a while back; customer called saying that RCD had tripped every morning when she got up for work. After asking whether any electrical work, sockets or switches changed etc had been done recently she explained she had purchased an American style fridge/freezer (bells & whistles number), coincidentally that's when the problem started.

As board was 16th edition type and located in cupboard next to kitchen rigged up a surface mounted socket on the unprotected side for the appliance to be plugged into temporarily. Hey presto no more tripping RCD, customer phoned manufacturer and appliance was changed for a unit that did not trip RCD.

As it happens I have got a massive fridge freezer, but I have had it for 5 years, so I would not think that was the problem. I will get up early and turn the fridge off and see whether that's the problem.

Thanks everyone for all your help it's really appreciated.
Cheers.
Ste

 

[jeremy]

For each circuit that you have that is supplied from the RCD, each morning, say 7am, switch off the MCB and see if the RCD trips. That should help narrow the problem down to an individual circuit at least.

If this doesn't isolate the circuit causing the trip it will be a n/e fault instead of a l/e fault which would probably remove the cause of something trying to switch on therefore I'd start looking at fixed wiring instead of appliances. I think this makes sense, it does to me, but it's been a very long day...