There are various ways of isolating circuits and each has its application, from Main Incomers, Out Going Ways, Life Safety, etc.

 

For the purpose of this example, we will use Schneider's range for this description, solely due to their organisation having the greatest market sector of switchgear breakers, the general will be translatable to other manufacturers however the exact detail may vary.

 

ACB's - Air Circuit Breakers

 

ACB's are commonly used for greater rated current applications typically ranging from 630A devices to 6300A

 

 

 

 

 

 

 

 

 

 

 

 

ACB Trip Protection Types

Micrologic 2.0

Micrologic 5.0

Micrologic 6.0

Micrologic 7.0

 

MCCB's - Moulded Case Circuit Breakers 

 

MCCB's are commonly used for medium rated current applications typically ranging from 16A devices to 1600A

 

 

 

 

 

 

 

 

 

 

 

 

 

MCCB Trip Protection Types

Micrologic 2.2/2.3/2.0

Micrologic 5.2/5.3/5.0

Micrologic 6.2/6.3/6.0

 

MCB's - Minature Circuit Breakers 

 

MCB's are commonly used for small rated current applications typically ranging from 2A devices to 63A

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Type B - Typically trips between 3 & 5 times full load current

Type B devices are commonly used in domestic systems and

light commercial applications where surges are low, for instance where

inrush currents may come from a small number of fluorescent fittings.

 

Type C - Typically trips between 5 & 10 times full load current

Type C MCBs are most suitable for commercial and industrial use,

where there are motors and perhaps a high number of fluorescent

fittings which, when switched off together may cause a high inrush

current. 

 

Type D - Typically trips between 10 & 20 times full load current

Type D units are for more specialist industrial use, where current

inrushes can be high, for example with X–ray machines and

transformers. They may require a lower earth loop impedance (Zs) to

achieve the operating times required.

 

 

F/S - BS88 Fuse Switch

 

MCCB's are commonly used for medium rated current applications typically ranging from 16A devices to 1600A

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Greater sizes of F/S do exist and if their use is unnegoctiable these can be used however due to their distinct size anything greater than 630A, it would be advised that ACB's or MCCB's should be used if possible.

 

There are various reasons why certain isolation breakers would be used and these are vast and to your specific and exact requirements.