In
A B Cables, there are three insulated cores and one insulated
neutral core (optional) laid around a bare or covered messenger wire,
which carries the load of the cable. There can be one additional power
core for street lighting.
Power
and Neutral Cores: Here, the conductor is composed of H2 or H4
grade Aluminium of Class 2 grade to IS: 8130/84. Popular sizes are
16mm2 to 95mm2. Again, insulation can be either cross linked
Polyethylene or Polyethylene.
Messenger
Conductor: These are made of either galvanized Steel or Aluminium
alloys.
Core
Identification: Either by number printing or by ridges on insulated
cores.
In
comparison to bare overhead lines, aerial bunched cable has very high
degree of safety and reliability due to the conductors being insulated
with the best dielectric medium. This ensures good protection against
ground and line faults leading to considerable increase in system
efficiency as against bare overhead lines. The problem of
free-clearance is also minimized.
Aerial
bunched cable system is specially suited in limited space conditions
like densely populated areas where laying of underground cables is
impossible or extremely expensive.