No so random RCD trupping

[lennyg]

This has been driving me crazy for a couple of years now, I keep thinking I've found the solution, then the problem resurfaces again - random tripping of my RCD.

Without going into great depth, my RCD has been tripping on a regular basis at various times of the day with no one consistent factor, or so I thought. I have always suspected my multiroom amp, which is a 100 watt amp that drives the speakers in my kitchen. I was able to replicate the trip sometimes, but the majority of the time I couldn't. If I left it unplugged then the issue seemed to go away. However, I have subsequently discovered that my PC, with only the power switched on at the wall, not the PC itself, along with the amp switched on needed to be on together to cause the trip. Strange that it was a combo that did it, but didn't explain the reason for it occurring at various times of the day.

It tripped again in the middle of the night, and whereas previously I wasn't easily able to replicate the problem, today I have been able to. After much experimenting, it seems that the boiler is the culprit regarding the various times, which I had suspected, however what I do not understand is that it takes a perfect storm of amp, computer plugged in and switched on at the wall and the boiler on for the issue to occur, and even then it doesn't happen all the time. I disconnected a pump from the boiler supply, which again seemed to rectify the trip issue, but I don't want to replace a pump as the fault doesn't occur unless both the amp and pc are in the equation. Can anybody please give me an idea why it takes the specific combo above to cause the tripping?

 

[ian.settle1]

Combined total of leakage current from what you have switched on equals the tripping current of RCD

 

[lennyg]

Combined total of leakage current from what you have switched on equals the tripping current of RCD

Thanks for the quick response. does it indicate a combination of faults on the appliances or should I be looking elsewhere at cabling etc...?

 

[R G]

There is no mention of any testing of the fixed wiring , I take it this has been done if so what are the results?

 

[SJD]

Thanks for the quick response. does it indicate a combination of faults on the appliances or should I be looking elsewhere at cabling etc...?

Some leakage may be due to a fault - for example a boiler pump - it shouldn't have any significant leakage - if there is, the chances are it will get worse and in due course trip the circuit on its own. If the pump really does test as poor insulation resistance, better to replace at your convenience sooner, rather than later but at short notice when it is very cold.

Some equipment has leakage as part of the design - for example, filter capacitors on the supply to some equipment (e.g. PC or a filtered / surge protected distribution board that is it plugged into).

It is also possible there is leakage on the fixed wiring, for example if there is any outdoor cabling (outdoor socket, security lights on the same circuit, etc), which are damp or corroded. Testing can identify this.

 

[GMES]

Lenny you have been a member for 4 years, but you have no information filled out in your profile as to your quals, experience etc. So are you a Diyer or an Electrician Please pm me and let me know so I can either leave it here or move it to the correct section, Thread closed until pm is received, thanks for your understanding.

Thread closed for now.