Strain Busbars
Busbars are electrical conductors which serve to pool up the power from different sources and distribute them to various feeders.  Busbars are generally made of copper or aluminium.  Busbars are found in substations, switchboards, distribution boards, etc. 

Busbars are sized according the current they carry.  Busbars are either flat or hollow.  This is to facilitate heat dissipation.  Busbars are supported by means of insulators.  Busbars are made flat or hollow to avoid the skin effect. 

Indoor busbars used in switchboards and distribution boards are usually flat. 

Outdoor busbars can either be hollow or strained.  Hollow busbars are rigid and are supported by means of hollow insulators.  It is easy to maintain these insulators as they are closer to the ground.  Their higher surface area minimizes the effect of corona.  They are more reliable.  However, they are expensive and require a larger area. 

Strained busbars are an overhead system of wires supported by insulators mounted usually on metallic frames.  The conductors are usually made of ACSR (Aluminium Core Steel Reinforced)

Other types of busbar include Insulated Phase busbars which consists of a rigid bar enclosed by a metallic enclosure and supported by insulator and Gas insulated busbars which consist of rigid conductors placed in a cylindrical tube filled with Sulphur hexafluoride gas)