Radial socket on landing and rear bedroom appears to be powered from lighting and radial

[Szico VII]

Hello all, first time posting here, was hoping for some theories/advice regarding a confusing situation. Essentially we were looking to add one or two sockets to a upstairs bedroom (40's build rewired in 80's I think with black/red colour system). It currently has two sockets and there is also one in the landing which according to the consumer unit is all wired radially of a separate fuse on the unit. Downstairs is on a ring main and there is another radial route for front two bedrooms from the consumer unit on a different fuse.

Now, my confusion comes because when trying to isolate this circuit, the sockets remained live on testing even with the proper fuse removed. I have since determined that if the lighting circuit MCB is also off, then these sockets are dead. However if EITHER the lighting fuse OR the radial fuse is on, these three sockets receive power. Any ideas what may be going on before I pull up the all the floorboards?

Additionally, this is an old consumer unit we are getting replaced as it doesn't have RCD protection and runs of the old 2 pin fuses but this will probably throw up testing problems afterwards if somehow the lighting circuit and this radial spur are connected somewhere

Many thanks

 

[Martyn Fletcher]

I'd be surprised if that was intentional. It's the uninitiated person's approach to electrics - if something doesn't work then turn things on and connect things together until it either works or goes bang.
Chances are in this instance they were content that the lights came on and left it at that before they stopped working again, or went bang; a partial victory.

Oh! The Ol' Bang Test Gang.
I've worked with a few of them in the past and more recently.
If you ever find yourself unfortunate enough to be in the same position, at the point when the power comes on, be somewhere else.

Hint: If looking over his shoulder you see a 2.5mm and a 6mm in the same 20A MCB and his answer is "I can't remember, we'll test it after"... Be somewhere else.
I walked out on the first day.

 

[Szico VII]

I wouldn't worry, the old man has a whole case of them from the doors for that reason...they will stay in the box for rest of time no doubt but hey ho. ;D

Will post and update once he has had a look at it

 

[Szico VII]

I wouldn't worry, the old man has a whole case of them from the doors for that reason...they will stay in the box for rest of time no doubt but hey ho. ;D

Will post and update once he has had a look at it