by sparx »
Thu Feb 11, 2010 5:24 pm
Hi,
for the purpose of your understanding, not to encourage 'dabbling':
A ring circuit starts and finishes at the same 30A fuse holder.
Its Neutral should start and finish at the same term. in the N bus-bar,
in the corresponding number /position as the Lives ie, L in fuse 2, N in term. 2 say.
likewise the earths (Circuit Protective Conductors). in term 2 of earth Bus-bar.
To determine if a circuit is a ring & if a particular socket is indeed on the ring rather than a double spur is more difficult and cannot be determined visually, but requires at least a test lamp (2 probe type, not neon test screwdriver!) plus the competance to use it safely.
This test requires the circuit to be dead, a suspect socket to be disconnected, the ends put in seperate connector blocks, the power restoring and each live tested. If both live then should be on ring, if only one live then is a double spur (not allowed by regs.).
Then power off & reconnect socket.
A way of doing checks which is ok for one unknown socket but very time consuming if all being tested!
Leckies can check insitu by plugging in expensive 'loop impedance' meter,
with circuit live, or using a low reading ohmmeter with dead circuit, this does need careful interpretation though.
regards Sparx