I had wall mounted spotlights in the lounge that were in wooden (double insulated) holders. I recently changed them for some modern ones in steel holders. I then found that the old supplies were without an earth and used two single cables with rubber insulation. This was probably from the date of construction of the house in 1958,
First idea was to rewire the whole place. I have done this in both of the houses I owned previously. However, having looked at the part P situation for DIY, and the fact that Stockport Council want about £600 before you can do anything legally, I gave that up as a non-starter.
So, I dug into the plaster and found that there was an earth wire (cut off and tucked up out of sight. With some effort, replastering, papering and repainting, I reinstated the earth. In this case it was a single uninsulated copper wire.
Finishing off the job, I did some continuity checks, as I have an aversion to blue flashes, bangs and smoke. I was puzzled by the results I got. This prompted me to do do some more checks.
The earth points on all of the sockets have a lowish resistance path back to the Earth bar on the supply. All of the equipment is working OK. There is no MCB or RCBO on the system, only the old fashioned Wylex fuse boxes.
Sorry for the long winded preamble, but the question is: -
When I test some of the 13 amp sockets around the house, I discovered that measuring Ohms between Earth pin and Neutral pin as per the drawing gives me a result that seems to defy physics.
Resistance with switch in off position - open circuit. Resistance with switch in on position - short circuit.
The sockets are all single pole switched units, where only the live is switched. The Neutral is connected at all times. There are no fuses or MCBs.
How can this be?????
On other circuits the reading is low, about 2 ohms regardless of the switch position.
I am puzzled. Anyone know what might be going on here?
Al.