Complete Mystery Around Home Electrical Damage - Can Any Electrician Offer an Answer?
Anonymous user 09/03/2024 - 3.30 PM
* We recently had an isolator switch installed by meter operators appointed by our energy provider (the installer was not a qualified electrician, but we were informed that was legal and fine)
• Following installation, one of the RCDs, which was operating across five circuits was permanently tripping and would not stay on
• We got round an electrician who did a ramp test and identified this was tripping at 21mA, however testing shortly after the installation had taken place found that three of the circuits were each showing earth leakage of over 40mA
* After some further testing, and lots of unplugging then replugging in, we found that three relatively new USB sockets which had been working fine were short-circuited and were no longer working, and were causing some of that earth leakage. We didn't however identify any other devices plugged in which had been causing the earth leakage
• There has never been an issue with that RCD previously – this problem only arose following the installation of the isolator switch.
• The three USB sockets had functioned perfectly before the installation, but did not work following installation
* The mystery is how installing an isolator switch, and turning the power off and on again could have led to these effects. The energy company have sent out another electrician to look at this who is saying it couldn't have been anything to do with installing the isolator switch. But from our perspective everything was working fine, then they installed that switch, and afterwards there were all these problems.
* This cost us hundreds of pounds to get sorted in electrician fees, and we believe the energy company should cover those costs, but so far they're refusing to do it, because they say installing the isolator switch couldn't have caused that.
Has anybody experienced something like this before? If we could get any insight into how this might have happened it would be really useful, because so far we've had two electricians look over it and neither seems to be able to give us an answer as to how it is even possible that this happened.
Are you a tradesperson and able to answer this question?
It is possible that a power surge damaged the electronics in the USB sockets. Switching off & on the main supply can cause a power surge, but lots of other things can generate power surges. It would be difficult to prove that the installation of the mains switch was the only cause.
We install all new consumer units with anti-surge protection which significantly reduces damage to electronic equipment caused by power surges.
You may be able to have an anti-surge device installed in your consumer unit or adjacent to it to stop this from happening again.
Hope this helps
Keith
Heat Light and Power Ltd
Answered1 September 2022
2
Anonymous user
It would be impossible for the installation of the main isolator cause damage any of the circuits connected to the consumer unit.
It is more likely that before the installation of the isolator your property had a very poor earth connection or earth loop impedance.
The engineer connecting the isolation switch would be required to insure a good earth connection to the property.
If the earth connection was very poor previous to the isolator being installed. Leakage to earth would not be causing the RCD to trip because there was a poor earth connection.
Now the earth connection is good the leakage to earth is causing the RCD to work properly.
Further more you cannot perform an insulation test with RCD sockets on a circuit.
If you use a 500v insulation tester you will damage the RCD sockets.
As an RCD socket has a built-in transformer thus will show as a short circuit on an insulation test.
This is probably why you was told there is a short circuit on the RCD sockets.
You need a experienced electrician with Expert knowledge in testing to find what is causing the leakage to earth.
If you need another electrician ensure that they have the City and Guilds 2391 or 2391-52. Qualification.
Hope this helps from a very experienced 2391 electrician
It wouldn't of been anything to do with the isolation switch. I would say you have had a fault develop independently. Also the electrician you got in sounds a bit incompetent. He should of found the source of the fault. I would forget about the isolation switch and get a new electrician.
Answered1 September 2022
0
Anonymous user
Hi Stuart,
In theory the installation of the double pole isolator by your energy company shouldn't have any effect on the continued use of your switches or sockets.
Basically they have switched off the power, added an isolator and switched the power back on.
I am personally aware of several installations of smart meters and isolators by energy companies where the polarity has been reversed (mains live and neutral the wrong way around) following installation.
Whilst it may seem strange , the majority of switches, sockets and appliances do still work with reversed polarity but this could have an effect on your USB sockets. I'm assuming that your own electrician's have checked that the energy company have installed the isolator with correct polarity?
If the polarity is correct then It's highly unlikely that the issue is from the isolator installation.
If in doubt and for peace of mind, it might be worth getting one of your electricians to carry out and EICR (Electrical Installation Condition Report) on your installation.
The testing and inspecting involved with the EICR should highlight any issues with the electrical installation.
Hope this helps.
Chris
KUH Electrical Ltd
Did the installer switch off the indivdual MCBs/ RCDs before isolating and fitting the double pole isolator? If he fitted the isolator and switched it on with all loads connected and on then in theory a surge may occur. Of course it could all just be coincidence that the USBs failed at that time.
