● The declared rating accurate.
An MCB the type shown Fig.
. Operating
time inversely proportional the fault current, the bigger the
fault current the quicker the fuse operates.
● Their operation more rapid than semi-enclosed fuses.
● They have small physical size and external arcing which permits
their use plug tops and small fuse carriers.
ADVANTAGES CARTRIDGE FUSES
● They have mechanical moving parts. The load current flows through the thermal and the
Fuse element
Glass ceramic body
End-cap
FIGURE 12.
● not possible see the fuse element broken. 12.
● The cartridge may shorted out wire silver foil extreme
cases bad practice.3 incorporates thermal and mag-
netic tripping device.2
Cartridge fuse. MCB overcomes this problem since automatic switch
which opens the event excessive current flowing the circuit and
can closed when the circuit returns normal.2.
● The element does not weaken with age. With larger size
cartridge fuses, lugs tags are sometimes brazed the end-caps fix
the fuse cartridge mechanically the carrier. Cartridge fuse construction illustrated Fig. They may also filled with
quartz sand absorb and extinguish the energy the arc when the car-
tridge brought into operation.
● They can replaced with incorrect cartridge. 12.
DISADVANTAGES CARTRIDGE FUSES
● They are more expensive replace than fuse elements that can be
re-wired.
● They are easy replace.
Miniature circuit breakers (BS 60898)
The disadvantage all fuses that when they have operated they must be
replaced.Basic Electrical Installation Work
242
to the body the fuse that they not blow off when the fuse oper-
ates
