RCD Tripping

[lisac]

Hi, I have a real problem which I have posed on here some time ago and was given lots of good advice. However I still have same prob and have more info so am asking for any advice again.

I will try to make this as short as possible!

I had new electrics installed nearly a year ago, we have a consumer unit with rcd. All tests carried out at time of install were fine.

When we moved into property we had a new washing machine installed which tripped the rcd, had that machine swapped out and the same thing happened.

We then had an engineer out and he tested the machine said it was fine.

The next thing to trip the rcd was the computer (I understand this is common) then the printer, then the LCD tv.

All of these things have been tripping the rcd since first bringing them into the property, however we can use each of them with no problem, infact we can use all at the same time with no problem but out of the blue it will trip, or when you plug in and switch on or off the socket it sometimes trips.

Just a couple of weeks ago our main tv in the living room started to trip the rcd and only last night the tumble dryer did it both have not done it before.

Now we have had our electrician back and he is baffled, he has done an R1R2 test, mega tested all downstairs sockets, he has put 500v through the system and found no faults, he has changed the rcd and the same happens.

Sorry if I'm using the wrong words but not up on electrician jargon!

He said the machine he used is showing 2.99 reading and that is what it should be.

So of course he thinks it is the appliances, unfortunately he does not have a PAT tester so we took our printer to a friends house last night, he has a 2 year old consumer unit with an rcd at 30 m/a.

We spent some time trying to make his rcd trip but it just wouldn't, as soon as we got the printer back home we took out every socket in the house and plugged the printer in, it tripped!

Took the printer out and plugged the lcd tv in same again, so the final thing we did was take the tv out so no plugs in and switched off all rcd switches, with the main rcd switch on we started to switch on the switches 1 to 5, a couple of times nothing but then it tripped on number 2 which is downstairs sockets, then number 4 which is kitchen sockets and then number 3 upstairs sockets, remember nothing is plugged in!

Sorry this is so long but I thought you would need all of the info I have, we are now looking at having to pay someone to come out and do a PAT test but I'm worried about where we go if the tests are fine!

 

[ricicle]

I think you have a frequent, but intermittent fault on the cabling somewhere.You say you had wiring done recently - what was the extent of this?

2.99M ohms would be a bit low on a completely new circuit even if it is a year or so old.Were all accessories physically checked and as much cabling as possible.Do you have any evidence of rodents or water leaks of any sort?

 

[lisac]

Was just trying to get everything out in one breath!!

 

[JohnD]

If you are paying an electrician to come in and do tests, you might consider having RCBOs fitted. they work out more expensive that a single RCD, but you have one fitted to each circuit (they replace the MCBs which you currently have). I understand you to say that tripping does not occur when you turn off the MCBs, so you probably have one or more Live/Earth leakages, and an RCBO will isolate these faults.

This brings two advantages:

1) If your problem is due to an accumulation of small leakages which vary, and together add up to enough to trip an RCD; by protecting each circuit individually, each of them may stay below the tripping threshold

2) A fault on one circuit will not cause all the other circuits to go off. this is a lot more convenient

3) If you still get trips on one of the circuits, you do at least know where to look for the problem. If all else fails it is possible to rewire the problem circuit.

I am inclined to suspect a damp-related or rodent problem.

p.s. I happen to be very fond of RCBOs, but it is true that they should be helpful in your situation

 

[lisac]

We had the whole house and new extension wired so complete rewire.

He got the 2.99 reading from the kitchen sockets, he used the same machine for all downstairs sockets but I only looked at it once. We have no evidence of rodents or water leaks that I know of, think we might have a wasp nest under the house, seen them come and go through the air brick, but the problem was here before the wasps!

Thanks

 

[JohnD]

I think I remember Secure telling us about a problem like this on a TNC-S installation where the Neutral had a poor connection? And the RCD tripped when the N tail was wiggled? But surely the electrician would have spotted it? Might be worth mentioning it to him though.

 

[canonc]

I have today had my RCD tested and it was tripping at 2.41 and was told that the reading was too high, and would need a new RCD

 

[ricicle]

Any water possibly leaking in small amounts from pipework behind an appliance such as washing m/c or dishwasher onto the socket that supplies it?
You might not notice this from the front of the appliance.

 

[lisac]

If you are paying an electrician to come in and do tests, you might consider having RCBOs fitted. they work out more expensive that a single RCD, but you have one fitted to each circuit (they replace the MCBs which you currently have). I understand you to say that tripping does not occur when you turn off the MCBs, so you probably have one or more Live/Earth leakages, and an RCBO will isolate these faults.

This brings two advantages:

1) If your problem is due to an accumulation of small leakages which vary, and together add up to enough to trip an RCD; by protecting each circuit individually, each of them may stay below the tripping threshold

2) A fault on one circuit will not cause all the other circuits to go off. this is a lot more convenient

3) If you still get trips on one of the circuits, you do at least know where to look for the problem. If all else fails it is possible to rewire the problem circuit.

I am inclined to suspect a damp-related or rodent problem.

p.s. I happen to be very fond of RCBOs, but it is true that they should be helpful in your situation

Hi JohnD, I think you gave me lots of advice last time!

When you say damp, are we talking leaking water or for example rising damp in the walls?

Also is it possible for the printer to trip out our rcd with nothing else plugged in but not trip our friends? Would this not mean the printer has a leak of 30 m/a, I really don't get it!

Thanks

 

[delmel]

Hi, I have a real problem which I have posed on here some time ago and was given lots of good advice. However I still have same prob and have more info so am asking for any advice again.

I will try to make this as short as possible!

I had new electrics installed nearly a year ago, we have a consumer unit with rcd. All tests carried out at time of install were fine.

When we moved into property we had a new washing machine installed which tripped the rcd, had that machine swapped out and the same thing happened.

We then had an engineer out and he tested the machine said it was fine.

The next thing to trip the rcd was the computer (I understand this is common) then the printer, then the LCD tv.

All of these things have been tripping the rcd since first bringing them into the property, however we can use each of them with no problem, infact we can use all at the same time with no problem but out of the blue it will trip, or when you plug in and switch on or off the socket it sometimes trips.

Just a couple of weeks ago our main tv in the living room started to trip the rcd and only last night the tumble dryer did it both have not done it before.

Now we have had our electrician back and he is baffled, he has done an R1R2 test, mega tested all downstairs sockets, he has put 500v through the system and found no faults, he has changed the rcd and the same happens.

Sorry if I'm using the wrong words but not up on electrician jargon!

He said the machine he used is showing 2.99 reading and that is what it should be.

So of course he thinks it is the appliances, unfortunately he does not have a PAT tester so we took our printer to a friends house last night, he has a 2 year old consumer unit with an rcd at 30 m/a.

We spent some time trying to make his rcd trip but it just wouldn't, as soon as we got the printer back home we took out every socket in the house and plugged the printer in, it tripped!

Took the printer out and plugged the lcd tv in same again, so the final thing we did was take the tv out so no plugs in and switched off all rcd switches, with the main rcd switch on we started to switch on the switches 1 to 5, a couple of times nothing but then it tripped on number 2 which is downstairs sockets, then number 4 which is kitchen sockets and then number 3 upstairs sockets, remember nothing is plugged in!

Sorry this is so long but I thought you would need all of the info I have, we are now looking at having to pay someone to come out and do a PAT test but I'm worried about where we go if the tests are fine!

Is it the same electrician who installed doing the tests, interested to see what make of CU has been used, as there is some complete crap out there. Certainly sounds like a fault somewhere, have you done any decorating and pulling around socket fronts.

 

[ricicle]

I have today had my RCD tested and it was tripping at 2.41 and was told that the reading was too high, and would need a new RCD

You have either mis-heard the information given or your electrician does not know what he is on about.

Try not to hi-jack posts (although you may have been trying to help)

 

[lisac]

Any water possibly leaking in small amounts from pipework behind an appliance such as washing m/c or dishwasher onto the socket that supplies it?
You might not notice this from the front of the appliance.

Hi, no I don't think so we have had the washing machine out and the dishwasher is intergrated but the socket is not close to it.

 

[JohnD]

Also is it possible for the printer to trip out our rcd with nothing else plugged in but not trip our friends? Would this not mean the printer has a leak of 30 m/a, I really don't get it!

No, you more likely have an accumulation of earth leaks.

Say, 10ma from the immersion heater, 6mA from cables installed in a damp place, 8mA from the washing machine, 5mA from the dishwasher, 8mA from the sockets in the garage which is a bit damp, 10mA from the electric shower, 12mA from the boiler and pump which have water in them, 2mA from the outside socket, 2 mA from the computer, 2mA from the printer, 3mA from the TV (and all these leakages vary up and down a bit from minute to minute)

add them all together and you trip the 30mA RCD

This is why RCBOs are handy, they allow you to have up to 30mA leakage on each protected circuit. An ordinary split-load CU allows you a TOTAL of 30mA

What make is your CU?

Can you post some pics?

 

[lisac]

[
My hubby took advise from another electrician today over the phone, and he did suggest checking for a fault between the neutral to earth and disconnect the neutrals and try them one at a time, but for him to be careful as they become live! However I'm not sure if he did try this as he is convinced it is the appliances.

 

[lisac]

Yes it is the same electrician, the make of CU is M2 which we have been told it is the same as MK?!?! Yes we have done decorating but like I said he has tested the sockets, but only downstairs so far.