We replace older fuseboards with modern 'consumer units' containing circuit breakers that can be switched back on after tripping. The switches we generally use are called 'RCBOs'; these switches combine overcurrent, short circuit and earth fault protection in one unit.
When replacing a fuseboard it is necessary to ensure the circuits connected to it are safe. Therefore we test every circuit and correct any faults we find on them before installing the new fuseboard.
Many consumer units in domestic or commercial properties In England & Wales contain fuses or MCBs (miniature circuit breakers) that only provide overcurrent and short circuit protection but have no earth fault protection; this would be provided by the installation of an 'RCD' (residual current device). In 1997 the Department of Trade and Industry published a report stating that their research suggested that 20% of electrical fires would be prevented by the use of RCDs in fuseboards.
Statistics for 2015/6 published by Electrical Safety First, a charity that campaigns for improved electrical safety show that 32 people are injured or killed by electrical fires in England and Wales each week.
The most common way of providing RCD protection is to install a new fuseboard or 'consumer unit' that includes one or more RCDs protecting the circuits fed by the fuse board. Often the RCDs will provide earth fault protection for up to 5 circuits. While this is safe, when earth fault conditions occur the RCD will trip and power will be lost to all those circuits. This can cause a lot of inconvenience, especially if a fridge or freezer is connected to one of the circuits, as any food inside the appliance could be spoiled. We fit fuseboards containing 'RCBO's. An 'RCBO' is a combined RCD and MCB and will provide overcurrent, short circuit and earth fault protection all in one switch. As each circuit will have a dedicated RCBO, 'nuisance tripping' of other circuits doesn't occur and the freezer doesn't defrost if other appliances in the home trip the RCD.
Another benefit of RCBOs is that in the event of an intermittent earth fault occurring, it would be obvious which circuit is faulty. With an RCD protecting several circuits, isolating the fault to an individual circuit may be difficult and more time consuming.
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