● They contain mechanical moving parts and therefore require regular
testing ensure satisfactory operation under fault conditions.
The circuit can restored when the fault removed pressing the ON
toggle.Overcurrent, short circuit and earth fault protection
243
electromagnetic devices normal operation but under overcurrent condi-
tions they activate and trip the MCB.3
MCBs Breaker, fits Wylex Standard consumer unit (Courtesy Wylex).
CHARACTERISTICS MCBs
MCB Type 60898 will trip instantly between three and five
times its rated current and also suitable for domestic and commercial
installations.
DISADVANTAGES MCBs
● They are relatively expensive but look the advantages see why
they are popular these days.
● The supply may safely restored unskilled operator.
FIGURE 12.
● faulty circuit may easily and quickly restored.
ADVANTAGES MCBs
● They have factory set operating characteristics. The toggle switch can also used disconnect the
circuit for maintenance isolation test the MCB for satisfactory
operation.
● The circuit provided with discrimination.
● Tripping characteristics and therefore circuit protection set the
installer. This latches the various mechanisms within the MCB and ‘makes’
the switch contact.
.
● faulty circuit may quickly identified.
● The circuit protection difficult interfere with
