I am converting a downstairs shower room into a utility room. I've removed
the shower and I now want to install some sockets in the room.
The existing electric shower circuit uses 10mm cable with a 45amp MCB.
Can I use the existing circuit and convert it to a radial circuit for 13amp
sockets, and can i use 2.5mm cable for the rest of the circuit?

Thanks

The existing electric shower circuit uses 10mm cable with a 45amp MCB.
Can I use the existing circuit and convert it to a radial circuit for
13amp
sockets.

Yes. You must swap the 45A MCB with a 32A MCB.

It is very sensible to use the existing 10mm circuit, as it will have low
voltage drop on a circuit expected to take heavy loading. It will prevent
the overloading of an existing ring and minimise disruption to decoration.

and can i use 2.5mm cable for the rest of the circuit?

No, you must use at least 4mm cable for the rest, and possibly (but probably
not) 6mm. 6mm would be a pain to work with for socket circuits.

If you use 2.5mm, the MCB must be changed for a 20A MCB, which is
insufficient to power the expected loads of a utility room.

Christian.

"Christian McArdle" wrote in message
. net...
The existing electric shower circuit uses 10mm cable with a 45amp MCB.
Can I use the existing circuit and convert it to a radial circuit for
13amp
sockets.

Yes. You must swap the 45A MCB with a 32A MCB.

It is very sensible to use the existing 10mm circuit, as it will have low
voltage drop on a circuit expected to take heavy loading. It will prevent
the overloading of an existing ring and minimise disruption to decoration.

and can i use 2.5mm cable for the rest of the circuit?

No, you must use at least 4mm cable for the rest, and possibly (but
probably
not) 6mm. 6mm would be a pain to work with for socket circuits.

If you use 2.5mm, the MCB must be changed for a 20A MCB, which is
insufficient to power the expected loads of a utility room.

Christian.

Surely it's possible to use 2.5 and a 32 amp breaker if he uses the 10mm
cable as a supply to a ring as opposed to a radial?

Richard.

Surely it's possible to use 2.5 and a 32 amp breaker if he uses the 10mm
cable as a supply to a ring as opposed to a radial?

That's what I've done many times in the past.
...

SJW
A.C.S. Ltd.

Surely it's possible to use 2.5 and a 32 amp breaker if he uses the 10mm
cable as a supply to a ring as opposed to a radial?

I don't see why not. However, it would be a slightly unusual layout, which
may confuse lesser electricians in the future. I suppose you could call it a
lasso circuit...

Christian.

"Christian McArdle" wrote in message
. net...
Surely it's possible to use 2.5 and a 32 amp breaker if he uses the 10mm
cable as a supply to a ring as opposed to a radial?

I don't see why not. However, it would be a slightly unusual layout, which
may confuse lesser electricians in the future. I suppose you could call it
a
lasso circuit...

Christian.

Personally I call it a pain in the a**e circuit but it's how my '70s semi is
wired - Large cable from CU to underfloor jointbox then ringed round the
sockets. Figure the sparky got a good deal on the large size cable or was
too idle to pull in the extra leg to the board.
Richard.

Personally I call it a pain in the a**e circuit but it's how my '70s semi
is
wired - Large cable from CU to underfloor jointbox then ringed round the
sockets.

I could see that it has advantages when wiring a tall house. Especially with
current standards as to the number of sockets to install, a 4 storey house
with consumer unit on ground floor could have earth loop impdedence/voltage
drop issues limiting the cable lengths. Running the ring after a length of
10mm could seriously reduce the impact of the initial trunk part of the
circuit on the available length.

Christian.