Belgian,
Ring circuits are used to supply 13A (BS1363) sockets & certain fixed appliances (up to 3Kw) via 13A fused connection units.
A ring circuit starts at a 30/32A MCB in the consumer unit, loops in & out of each socket / fused connection unit in the circuit & back to the same 30/32A MCB.
Minimum cable size is 2.5 sq mm Cu/PVC.
A ring circuit may supply an unlimited number of sockets, in a maximum floor area of 100 sq M, providing that the known or estimated load does not exceed the value of the MCB.
Radial socket circuits start at the MCB, loop in & out of each socket in the circuit & terminate at the furthest socket in the circuit. (The same as Belgian practice I assume.)
Radial circuits may also serve an unlimited number of sockets, in a given floor area, providing that the known or estimated load does not exceed the value of the MCB.
20A Radial:
Min. cable size = 2.5 sq mm Cu/PVC.
Max floor area served = 50 sq M.
30 or 32A Radial:
Min. cable size = 4 sq mm Cu/PVC.
Max floor area served = 75 sq M.
Most UK residential wiring is carried out in PVC insulated & PVC sheathed "twin & earth" cable, similar to US "Romex" cable.
The cable is usually run in building voids, under floors, above ceilings & within timber stud partitions without any conduit tubing.
When run under plaster in solid walls (frequently encountered in England!) it should be protected by capping or conduit. This conduit usually only runs from the socket up to the ceiling or down to the floor, depending on wiring & construction methods.
Rewiring or adding extra points at a later date can be a major pain in the a***!
I have a copy of Legrand's International Wiring Guide, which illustrates the basics of the 4 main wiring standards; US, UK, French & German.
I will attempt to e-mail it to Paul (hopefully sometime this week) for him to post, as I think it may help us understand each other's systems.
