Trip switch problems - any ideas?

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Hello - Over the past month or so we have experienced several power cuts, and during one cut, my main trip switch went. It was early in the morning while I was still in bed, and I was concerned as had I been away from home for any period, the contents of my freezer would have been lost.

I contacted Western power, who told me that the power cut would not cause the switch to trip, and indeed, during a second power cut the same day, it did not! However, because I was told that sometimes a power cut, or more correctly, the attempts to re-connect, can highlight a problem with the wiring in the house, I called an electrician. He could find nothing wrong, and I'm not entirely sure what he tested for, but think it was something to do with leakage or perhaps earth!?!

All seemed well until last Friday, when again the trip went, mid morning, and reset with no problems since. As before, it was the main switch that went, but none of the individual switches, and as I was not using kitchen appliances (usual suspects)was a little puzzled, and did make a note to look into again. However, I have just found out from my neighbour that there was a power cut, albeit not for long, last Friday.

Any ideas or suggestions of where I should go from here would be appreciated. I do realise that these things can be difficult to diagnose, but also am worried about the possibly open ended cost of such investigation.

Thank you
 
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Can you post a photo of your trip switches and point out the main one that went? It could be that the number of devices starting up at the same time is causing an overload which doesn't happen if they are started up one at a time.
 
The "main trip" is presumablly a RCD. The rest of this post is based on the assumption that it is.

My guess would be that some of your appliances have a surge of leakage when switched on and switching everything on at once can cause enough leakage to trip the RCD, especially if the switchon happens at the peak of the AC waveform.

There are two possible courses of action I can see here.

One would be to get your appliances PAT tested. This should reveal any appliances which have unusually high leakage. I'm not sure how well PAT testers pick up surges of leakage at switchon though.

The other would be to replace the CU with a system based arround a main switch and RCBOs rather than one with a main RCD and MCBs. If the problem is stuff on multiple circuits adding up to a trip this should solve it. If the problem is all on one circuit this should reveal which circuit is the problem and reduce the inconviniance when it does trip.
 
Thanks so much for quick responses.

Unfortunately no battery left in camera - but my switches are as follows:

A number of individual switches, which I think must be MCB's with notations above with such as Ring Main - Lights - etc., behind a clear removable panel. To the right of this there is a lever type switch marked as 'main switch', which has an On and Off position, which I refer to as my 'trip switch' - this is the one that is tripping to the off position, but with none of the individual MCB's being in the off position.

I'm not sure if this is an RCB ? - but from what you are saying, to possibly solve the problem it would be a good idea to change to a system using RCBO's - Have I understood correctly?

The only thing I'm not quite sure I understand is the trip goes when the power goes OFF, not when it is restored. I know this because the first power cut lasted for several hours, and although I put the main switch back to the on position, there was still no power. However, I will look into the PAT test of appliances.

Thanks again.
 
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Does this main switch have any other writing or numbers? What colour is the switch, red? Does it have a button that says "test" on it too?

RCBO's cost around £35 each retail

you could charge your camera battery overnight and post tomorrow
 
You need to get a torch and read the writing on your switch it is highly likely to be an rcd.

Now depending on the earthing system you have from the supplier or not, as the case might be that sets the parameters for the rcd size, and type.

If the switch is integrated in the fuse board it is likely to be a 30 mA type B, rated at xyz amps.

If the switch is on its own, between the supply cables and the fuse board (cu) it could be a TT system.

If you can't photo then you have to post back the details and a better level of information for us to work on.


Rcds trip due to fault or sometimes due to an earth leakage build up. Common failure is associated with damp, so check all outside lights, boxes and cables (garages, sheds, external) for water.

Have you changed anything recently, just before the issue started? Any new appliances, pcs or such item.

Has the fault only happend when you are asleep, or away to exclude items such as a kettle or iron being the cause?

Have any of you neighbours experienced similar?
 
Hey - thanks so much for everyone sparing the time to address with my problem.

I have put the batteries on charge for the camera and will post photo in the morning.

In case detail of writing not clear, the following may be helpful - though 'double dutch' to me!

The consumer unit is a Memera 21 - with 8 x MCB's - 2 x 5A/2 x 16A/4 x 32A
Type tested to : - BS 5486 - P + 13
Total loading 80A - Not to be exceeded - 8 QIEH
The main switch ( RCD?) - )what I call the trip switch) - is labelled as
MEM - 404 ELHNC - 1 n = 80A - 1 oAn = 30 MA - Un = 240 V ~

ELCB circuit switches off when earth fault occurs. To restore power turn to On.

It is grey, not red and has a push lever - up for On and down for OFF - with a test button above - marked test button T

I have one outside light, which I will check for water. I have not changed anything recently, or got any new appliances. The only common factor has been a power cut, and what I referred to as the 'usual suspects' - to me that is the iron and the kettle - were not in use on any of the occassions. The only other unusual thing was around the time of the second power cut, one of my telephones would no longer work when power restored. It had a sealed type plug/transformer so could not just change a fuse.

Hope this is of some help.
 
In my experience it is not unheard of for RCDs to operate when there is a power failure.
Indeed. In fact, in my personal experience, it's actually quite common - and one can (as some have done in this thread) speculate about the mechanism(s). I don't think that it is, per se, anything to get concerned about.

Changing from one/two RCDs to multiple RCBOs would obviously be likely to reduce, maybe even eliminate, the 'inconvenience' resulting from this phenomenon (one suspects that few, if any, RCBOs would trip in the case of a power cut) - but, given the rarity f power cuts (at least at present!), I doubt that the cost of such a change would be justified for this reason alone.

Kind Regards, John
 
Thanks so much for interesting observations - I did search for previous posts on this fault , but hadn't thought of putting in the actual make of the consumer unit, so thanks, could posible be of use for any future searches on this great forum!

I am very interested that from your experience it has been known that RCD's can trip when there is a power cut - because of course I was categorically told by Western Power that this could not happen - and could only be a fault in the wiring in the house!

As there was nothing obviously wrong in the house wiring, and from what I surmise, to replace my MCB's would be very expensive - 8 x RCBO's at c. £35 each? - I agree, it's not worth it.

Hopefully we will not have too many power cuts, and if we do, they do not occur when I am away from home. If I have any more problems I now have all this valuable information to refer to.

Thanks so much to all.
Regards
Anne
 
Your picture, ann:

CUPicture.jpg


I have had this problem with this board but unfortunately I cannot resolve it for you as I never went back to it!

Get the RCD tested, then get all circuits IR tested, both by a competent spark.

If they pass, it could be a faulty appliance.
 
Get the RCD tested, then get all circuits IR tested, both by a competent spark. If they pass, it could be a faulty appliance.
It could, but I would have thought it extremely unlikely that either an IR problem or a faulty appliance would manifest itself (only) as RCD tripping when there was a power cut, wouldn't you? A 'trigger happy' RCD could, of course, be at least a partial explanation - so, if one were concerned, it might be worth getting that checked. However, as I and others have said, passive RCDs tripping in response to power cuts in the absence of any faults (or RCD malfunction) is far from unknown (and even the OP experienced only one RCD trip during the course of several power cuts).

Anne, do you remember the circumstances surrounding the power cut that caused your RCD to trip? Out in the sticks where I am (and possibly because there are lots of overhead power lines), lightning seems to be the most common cause of (usually very brief) power cuts - and in such situations one can't be sure whether it is the power cut or the lightning that caused an RCD to trip. It would also be interesting to know whether the RCD tripped when the power went off or when it came back on - but, particularly since you were in bed, I presume you don't know the answer to that!

Kind Regards, John.
 

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