Circuit breakers

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Circuit breakers
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Starter Task Q1 Which two mains wires carry the
current if a device is working
normally? Q2 Where should the Earth wire be
connected? Q3 If the body of an appliance becomes
live, what job does the Earth wire do? Q4 What
would happen if the Earth wire were not
connected and someone touched the
appliance? Q5 What sort of appliances do not
need an Earth wire?
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A current flowing in a coil of wire creates a
magnetic field. Circuit breakers use this field
to detect the size of the current
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and now the Magnetic Circuit Breaker (MCB)
which makes use of the magnetic effects of large
currents
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The RCD (residual current device)
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Q1 What is created around a coil with an
electric current flowing in it? Q2 What happens
to the strength of the field if the current gets
bigger? Q3 How does the MCB use a magnetic
field? Q4 When should the MCB be used? Q5 How
does the RCD use a magnetic field? Q6 When should
the RCD be used?