Wimpey domestic wiring

[CS1945]

I intend to add additional 13 amp sockets in my lounge by extending the ring but there doesn't appear to be one! All sockets upstairs and downstairs are powered from one 30 amp fuse in the consumer unit which has three red wires going in to it. With one or two exceptions, all sockets only have one twin and earth cable - there is no ring main.
One socket in the lounge powers a socket in the dining room - presumably as a spur since there is only 240 volts on one cable. However, whilst doing a few checks I discovered that the 'spur' cable will power the dining room socket with only the red lead connected.
The house is Wimpey built, 30 years ago and I haven't a clue as to what they have done. Any help/suggestions would be appreciated.
Thanks!

 

[securespark]

Neither have I......

 

[toasty]

Junction boxes under the floor maybe?

I can't think how else you'd have only one cable to each socket and then only 3 at the CU.

 

[comms]

Ringmain run for upstairs sockets then all groundfloor sockets run as spurs from the upstairs ringmain ?
3 cables at the 30 amp fuse could mean a spur has been run directly from this point.

 

[CS1945]

I intend to add additional 13 amp sockets in my lounge by extending the ring but there doesn't appear to be one! All sockets upstairs and downstairs are powered from one 30 amp fuse in the consumer unit which has three red wires going in to it. With one or two exceptions, all sockets only have one twin and earth cable - there is no ring main.
One socket in the lounge powers a socket in the dining room - presumably as a spur since there is only 240 volts on one cable. However, whilst doing a few checks I discovered that the 'spur' cable will power the dining room socket with only the red lead connected.
The house is Wimpey built, 30 years ago and I haven't a clue as to what they have done. Any help/suggestions would be appreciated.
Thanks!

Thanks for all your responses - there isn't a ring main in any of the upstairs rooms either. A possible ring main in the loft with spurs to both floors OR 3 radial circuits. I have run out of options folks and I guess I wilol have to put a new ring main in - just for one room!