I have done the inspection and testing in a three storey house today, on the job sheet it said to reinstall the hall light as well.
The tenant said the hall light had been taken down because the shower was leaking and water was running down through the light fitting, the tenant said he had an electric shock whilst he was in the shower, so an electrician had taken the light fitting down.
Then he went on to say he had also had an electric shock when touched the dishwasher and another electrician had replaced the plug socket in the back of the cupboard under the sink, though it looks original to me.
There is a 30 mA DP RCD upfront of the old Square D consumer unit with BS3871 MCBs, so I turned the RCD off along with the CU main switch and did a 250 volt insulation test of the whole installation lives to earth with everything connected, 0.00 Mohm absolutely no resistance at all.
So I tested the RCD with the CU main switch off, tested perfectly both on time tests and the ramp test, tripping at 25 mA.
I now had a C1 to start the list of observations and I knew the tenant had been shocked whilst using the shower and dishwasher. So it was a case of either find send fix it or advise that the installation needed to be isolated. A couple of hours later after breaking the installation down I was replacing the socket circuit cable drops behind the central heating boiler that the plumber had drilled whilst installing the boiler some years ago creating an 8 ohm resistance fault between the neutral and CPC on one leg of the ring.
It is now all sorted out, but I am pondering two things, first that the healthy RCD didn’t trip despite a zero insulation test result, secondly that appears that two electricians went to investigate two different electric shock events at different times and presumably neither of them did a global insulation test.
I have done the inspection and testing in a three storey house today, on the job sheet it said to reinstall the hall light as well.
The tenant said the hall light had been taken down because the shower was leaking and water was running down through the light fitting, the tenant said he had an electric shock whilst he was in the shower, so an electrician had taken the light fitting down.
Then he went on to say he had also had an electric shock when touched the dishwasher and another electrician had replaced the plug socket in the back of the cupboard under the sink, though it looks original to me.
There is a 30 mA DP RCD upfront of the old Square D consumer unit with BS3871 MCBs, so I turned the RCD off along with the CU main switch and did a 250 volt insulation test of the whole installation lives to earth with everything connected, 0.00 Mohm absolutely no resistance at all.
So I tested the RCD with the CU main switch off, tested perfectly both on time tests and the ramp test, tripping at 25 mA.
I now had a C1 to start the list of observations and I knew the tenant had been shocked whilst using the shower and dishwasher. So it was a case of either find send fix it or advise that the installation needed to be isolated. A couple of hours later after breaking the installation down I was replacing the socket circuit cable drops behind the central heating boiler that the plumber had drilled whilst installing the boiler some years ago creating an 8 ohm resistance fault between the neutral and CPC on one leg of the ring.
It is now all sorted out, but I am pondering two things, first that the healthy RCD didn’t trip despite a zero insulation test result, secondly that appears that two electricians went to investigate two different electric shock events at different times and presumably neither of them did a global insulation test.
