but I would expect the extension socket to be connected to the back of the front plate of the master socket on terminals 2 & 5. so if not conencted there how is the extension conencted to the phone line?
When I connect to the test socket i lose BB but keep the phone line-is that normal?
Could the HH be goosed?
if the hub works in whatever socket then it must be ok - so looking for another reason
There is a white wire that comes out of the bottom of the master socket & goes down the back of the skirting board-this might be leading to the extension under the floorboards??
the white wire must be conencted to the terminals a & b on the back of the master assuming that is the master on not just someone used an nte5 and then runs to extension. does the extenal wires connect to the master can you see outside?
so the extension has been wired incorrectly in that instead of conencting to the terminals 2 & 5 on the faceplate it must be (the white wire) conencted to the terminal a & b on the backplate. if that is the case then your extension must still work when faceplate removed and that test socket inthis instance does not disconnect all your internal wiring