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