MCB overcomes this problem since automatic switch
which opens the event excessive current flowing the circuit and
can closed when the circuit returns normal.
● The cartridge may shorted out wire silver foil extreme
cases bad practice.2.
DISADVANTAGES CARTRIDGE FUSES
● They are more expensive replace than fuse elements that can be
re-wired. 12. 12. With larger size
cartridge fuses, lugs tags are sometimes brazed the end-caps fix
the fuse cartridge mechanically the carrier.
● They have small physical size and external arcing which permits
their use plug tops and small fuse carriers.
● They are easy replace.
● Their operation more rapid than semi-enclosed fuses.
● The element does not weaken with age.
An MCB the type shown Fig. The load current flows through the thermal and the
Fuse element
Glass ceramic body
End-cap
FIGURE 12.2
Cartridge fuse.
● They can replaced with incorrect cartridge.Basic Electrical Installation Work
242
to the body the fuse that they not blow off when the fuse oper-
ates.
● not possible see the fuse element broken.
● The declared rating accurate.
Miniature circuit breakers (BS 60898)
The disadvantage all fuses that when they have operated they must be
replaced. Cartridge fuse construction illustrated Fig.
ADVANTAGES CARTRIDGE FUSES
● They have mechanical moving parts. They may also filled with
quartz sand absorb and extinguish the energy the arc when the car-
tridge brought into operation. Operating
time inversely proportional the fault current, the bigger the
fault current the quicker the fuse operates.
.3 incorporates thermal and mag-
netic tripping device
