A question I'm sure the experienced electricians will have heard a zillion times... how do you (inexpensively) identify the cause of nuisance RCD tripping? I've spent the last few hours reading all over the 'net for answers and my head is now buzzing.
As briefly as possible, I know pretty much nil about electrics and I've had problems ever since moving into a new flat about 4 years ago with intermittent (maybe about 4 or 5 times a year) nuisance RCD tripping. Well, I say RCD, sometimes it's a specific MCB which trips instead (the one labelled 'sockets'). Very rarely, resetting the RCD immediately causes the 'sockets' MCB to trip - doesn't happen very often though - mostly just resetting the RCD gets things going again first time. At only 4 or 5 times a year I could just about live with it. Nothing in particular seemed to cause it to happen - it's not like it happens when a particular item is turned on or off. Sometimes it happens during the day, sometimes it happens during the middle of the night when nobody's awake, sometimes it happens when nobody's at home (even so, obviously, there are things which are running 24/7 whether there's anyone around or not - fridge freezer, UPS, server, mobile chargers, set-top boxes etc).
Today, however, things took a definite turn for the worse... the RCD tripped about a dozen times throughout the day. Resetting got things going again, but sometimes for only a couple of minutes, sometimes for a couple of hours. It did occur to me it might be related to the weather (100mph+ winds locally!), or that may just be coincidence, but it inspired me to try to get to the bottom of why this happens at all. Reading about it online it seems like it can become quite expensive to get an electrician in if it only happens as infrequently as it does (well, infrequent apart from today)... and there's no guarantee to ever get to the bottom of it. I'm making the assumption that the cause is something plugged into a socket (as it's only ever the 'sockets' MCB or RCD that trips). If I were to buy a plugin RCD and plug one item into it at a time, either waiting for the next trip or for the problem to disappear, would this be a valid test? Apart from the fact this could take years to narrow down to an exact item which causes it given that it (normally) happens so infrequently, I'm guessing the plugin RCD would either need to be rated less than 30mA or react faster than the one installed in the consumer unit (otherwise the one in the consumer unit might react first meaning that I'd never get the trip happening at the plugin version). So, I guess the question is, is this a valid test and does even such a plugin RCD exist? Or is there in fact a better way to do get to the bottom of this that isn't going to mean I'm keeping an electrician on the payroll for months as the problem will almost certainly never happen when s/he's here (it's not that I don't want to pay to get a pro in - I'm happy to do so, but I don't like the idea of the possibility of paying a pro and still never getting to the bottom of it before I run out of money).
Many thanks,
Graeme
Snapshot of my consumer unit
As briefly as possible, I know pretty much nil about electrics and I've had problems ever since moving into a new flat about 4 years ago with intermittent (maybe about 4 or 5 times a year) nuisance RCD tripping. Well, I say RCD, sometimes it's a specific MCB which trips instead (the one labelled 'sockets'). Very rarely, resetting the RCD immediately causes the 'sockets' MCB to trip - doesn't happen very often though - mostly just resetting the RCD gets things going again first time. At only 4 or 5 times a year I could just about live with it. Nothing in particular seemed to cause it to happen - it's not like it happens when a particular item is turned on or off. Sometimes it happens during the day, sometimes it happens during the middle of the night when nobody's awake, sometimes it happens when nobody's at home (even so, obviously, there are things which are running 24/7 whether there's anyone around or not - fridge freezer, UPS, server, mobile chargers, set-top boxes etc).
Today, however, things took a definite turn for the worse... the RCD tripped about a dozen times throughout the day. Resetting got things going again, but sometimes for only a couple of minutes, sometimes for a couple of hours. It did occur to me it might be related to the weather (100mph+ winds locally!), or that may just be coincidence, but it inspired me to try to get to the bottom of why this happens at all. Reading about it online it seems like it can become quite expensive to get an electrician in if it only happens as infrequently as it does (well, infrequent apart from today)... and there's no guarantee to ever get to the bottom of it. I'm making the assumption that the cause is something plugged into a socket (as it's only ever the 'sockets' MCB or RCD that trips). If I were to buy a plugin RCD and plug one item into it at a time, either waiting for the next trip or for the problem to disappear, would this be a valid test? Apart from the fact this could take years to narrow down to an exact item which causes it given that it (normally) happens so infrequently, I'm guessing the plugin RCD would either need to be rated less than 30mA or react faster than the one installed in the consumer unit (otherwise the one in the consumer unit might react first meaning that I'd never get the trip happening at the plugin version). So, I guess the question is, is this a valid test and does even such a plugin RCD exist? Or is there in fact a better way to do get to the bottom of this that isn't going to mean I'm keeping an electrician on the payroll for months as the problem will almost certainly never happen when s/he's here (it's not that I don't want to pay to get a pro in - I'm happy to do so, but I don't like the idea of the possibility of paying a pro and still never getting to the bottom of it before I run out of money).
Many thanks,
Graeme
Snapshot of my consumer unit