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RING MAINS
This is the
ring of wires that circles through the house,
each house normally has 3 ring mains, 1 for
the downstairs, 1 for the kitchen and 1 for
the upstairs. The power starts from the consumer
unit arriving at each socket and finishing
at the consumer unit.
Both ends of
the cable are connected in the same terminals
in the consumer unit. The 2.5mm cable which
comprises of a live, neutral and earth and
is protected by a 32A circuit breaker unless
you have an old consumer unit and then it
will be 30A (if yours is an old consumer unit
you should consider an upgrade see our electrical
safety page,
The benefit
of a ring main is the current runs in both
directions witch imposing less load on the
cables. If the cable didn’t return to
the consumer unit then it would be called
a radial
circuit. The maximum distance for a ring
main is 100metres and on a 32A circuit must
not exceed 7200WATTS. There is no maximum
number of sockets allowed on the ring main
although there are still restrictions on how
much power and for how long, a ring main may
carry.
The
picture below shows the back of a socket on
a ring main
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There is two
2.5mm 2core and earth cables at every socket
in the ring, this is the same for a radial
circuit apart from the last socket will only
have one.
There is no
limit to the number of sockets you can have
on a ring main but there is a limit to the
number of spurs. If you want to add an additional
socket in a room you may consider a spur from
the ring main, the only thing with a spur
is, you are limited if you ever want to add
any more sockets from the spur. You are only
allowed to spur from the ring main once so
I would always try to keep any addition socket
you require in the ring main a spur should
always be the last resort, then if in the
future you ever require any more sockets you
would be able to do so easily.
See extend
the ring main
For regulations
governing heights of sockets etc, please click
here
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