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3. Switch disconnectors

Figure 8.5 - Switch disconnectors; Left – ABB’s motorized
switch disconnector 160-2500A; Right – Schneider Electric’s
low-voltage disconnect switch with free tripping 80-3200A

Switch disconnectors combine the properties of (load) switches
and disconnectors. In this case, too, there are a variety of designs
such as “normal” switch disconnectors, fuse- switch-disconnectors
and circuit breakers.
Fuse-switch-disconnectors are not legally permitted in all
countries.

5. Circuit breakers

Circuit breakers are mechanical switching devices, capable of
making, carrying and breaking currents under normal circuit
conditions and also making, carrying for a specified time and
breaking currents under specified abnormal circuit conditions such
as those of short-circuit (IEC 60947-2).
They thus also fulfil the requirements of (load) switches. Circuit
breakers are often designed so that they can fulfil the requirements
for disconnectors.

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