power supply

[jacko50]

I recently had my house wiring changed around (plug sockets) now my fuse box keeps triping off sometimes just the sockets and other times everything goes off, i have had the sparky back but he says he can,t find anything wrong. I also spoke to another one and he said that without seeing it , it sounds to him like an earth leak, so it will stay on until the resistance builds up then it will trip off then i can put it back on until it builds up again and then it will go off again, has any kind soul got any advice thanks.

[beso]

The description of the electrician's explanation does not make sense at all. However it probably is an earth leakage. If it is an old house it may have just had the earth leakage system added during this work.

The most common earth leakage problems occur in refrigerators because the motor windings actually are immersed in the refrigerant fluid that runs in the earthed pipes. The problem can also be intermittent but you might check to see if it trips when the thermostat cuts on on the fridge.

Otherwise if you can get hold of a suitable safety isolation transformer try running the fridge through it and see if the problem stops.

Note if it is an earth leakage problem the breaker that trips must be and RCD type. Usually the main switch is not RCD with earth leakage protection done by the circuit breakers. If everything goes off it would have to be the main switch tripping.Check to see if the main switch has earth leakage facilities. If it doesn't then it won't be an earth leakage problem but a seriously big overcurrent.

Another problem can be the interference filter capacitors in appliances with switch mode power supplies such as computers, televisions and many other modern appliance. They actually have a small amount of earth leakage in normal operation. Indeed if you get enough onto one circuit they can trip the RCD breaker. This usually happens during voltage surges. I have seen it in a circuit that had eleven computers connected.

If there is a faulty component in a power supply there can also be a leak during surges. Try disconnecting appliances and work out which one cause the problem. If it is an earth leak problem my money is definitely on the fridge.

[Hymie]

I would add the central heating pump as a possible candidate - the seal on the pump goes, allowing water to reach the pump windings, causing an earth leakage trip.

But as the previous answer, it can be solved by a process of illimination, once you have isolated the electrical item causing the trips.

If the tripping becomes continuous, then detecting the faulty appliance becomes easier - you can isolate each circuit at the fuse/distribution box in turn, and then track down the faulty appliance in the circuit which is tripping.

As always - take care whenever working on mains circuits.

[jacko50]

thanks for your answers guys I will show this to the person i got the info off in the first place and see if this helps him.once again thank you very much.

[mike5281]

Whilst you do not say how often this occurs - I would suggest at the fuseboard, switching off the individual fuses in turn for a length of time and then back on. Do this for all the fuses to help you by a process of elimination identify which circuit is giving you the problem.(If the switch does not trip when a particular fuse is off / withdrawn - you've cracked it )Then when the offending circuit fuse is identified - then switch off /isolate all individual components on that circuit n a similar fashion to the fuses process to identify what appliance is giving the problem.Hope this helps.

[Mortartube]

It is possible that your fridge or freezer has a fault and causes a trip when the motor cuts in, otherwise, do you run any very old valve electric equipment? Radio, guitar amp etc as valves can cause modern rcd consumer units to trip.

[Disco Fever]

Well said Beso as I would of explained it the same way and to Mike5281 if you turn off the Miniture Circuit Breaker (MCB) the neutral and earth are still connected so if there is an earth fault to neutral the Residual Current Device (RCD) will still see the fault and trip out. I have come across this problem before and as i'm a sparky of over 20 years experience I will always endeavour to find the fault weather it's an appliance or faulty wiring with a piece of kit called an Insulation Resistance Tester or commonly known as a Megger, it puts out a voltage between 250 and 1000volts and can find 99% of faults including damp but you can't test stuff like computers as it blows em up I know this from experience.
I suggest you get another sparky in Jacko50 with years of experience as they can normally find faults within an hour.

[jacko50]

thanks for the answeres guys ,my leky went off aprox every six hours when it first started doing it but now it stays on for five or six days. it is usualy the same one wich is downstairs sockets mut sometimes the whole lot goes off .