In a bout of man flu, I lay in bed wondering: If the MCB is supposed
to protect the cable to the fitting, and the fuse in the plug is
supposed to protect the cable to the appliance, how is the single bit
of 2.5mm T+E run to a single socket spur adequately protected by
You've basically got 2 bits of 2.5mm in parallel (usually unequal
lengths), feeding a single bit of 2.5mm. 32A MCB.
Whereas if it was a standard radial circuit, you'd have just the
single bit of 2.5mm, and you'd only be allowed a 20A MCB on it. (IIRC
they even dropped the 2.5mm rating down to 18A, which is "correct" in
accordance with the calculations, but then increased it back to 20A
because that's what everyone does anyway).
I'm not worried. I just don't see the logic.
I have 10cm of 2.5mm T+E protected by a 40A MCB on the cooker circuit
(feeding a socket that can only supply the gas hob ignition) and that
seems very wrong too - but wiring a socket in 6mm is just too painful.
However, the cooker circuit may yet drop back to 32A (because I
suspect that's all it needs) which makes it no worse than the socket
spur discussed above.