| Consumer
unit or Fusebox
A consumer unit or fusebox is used
to control and distribute electricity
around our homes.
They usually contain:
A) Main switch
B) Fuses or Circuit Breakers
C) Residual Current Device
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Modern
Consumer Unit with main switch
(A), circuit breakers (B) and
RCDs (C)
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Old
style Fusebox with main switch
(A), re-wireable fuses (B) and
no RCD
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| Main Switch
The main switch allows you to turn
off the electricity supply to your
electrical installation. Some electrical
installations have more than one mains
switch, for example, if your home
is heated by electric storage heaters,
you may have a separate consumer unit
(fuse box) for them. The consumer
unit should be easy to get to, so
find out where the mains switch is
to turn the electricity off in an
emergency.
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Fuses
Rewirable
fuses have a piece of special fuse
wire running between two screws. When
a fault or overload current flows
through the fuse wire, it will become
hot, and melt when the current goes
above an acceptable level. The melted
fuse breaks the circuit, disconnecting
the faulty circuit.
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| Circuit
Breaker (MCB)
Circuit breakers are automatic protection
devices fitted in the consumer unit
which switch off a circuit if there
is a fault. Circuit breakers are similar
in size to fuseholders, but give more
precise protection than fuses. When
they ‘trip’, you can simply
reset the switch. However, you first
need to find and correct the fault.
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| Residual
Current Device (RCD)
An RCD, or Residual Current Device,
is a switching device that trips a
circuit under certain conditions,
and disconnects the electricity supply.
If your electrical installation includes
one or more RCDs, test them regularly.
You can do this by following the instruction
label, which should be near the RCD.
The label should read as follows:
‘This installation, or part
of it, is protected by a device which
automatically switches off the supply
if an earth fault develops.
Test quarterly (every three months)
by pressing the button marked ‘T’
or ‘Test’.’ The
device should switch off the supply.
You should then switch it back on
to restore the supply. If the device
does not switch off the supply when
you press the button, contact an electrician.
Testing the button every three months
is important. However, do not hold
the test button for a long period
if the device does not trip. If the
RCD does not switch off the supply
when you press the test button, get
advice from a registered electrician.
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| Old Fuseboxes
If your fusebox has a wooden back,
cast iron switches, or a haphazard
mixture of fuses it is likely that
it dates back to before the 1960s
and will need to be replaced.
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Information from The Electrical Safety
Council, see www.esc.org.uk
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0117 914 0304
