The document outlines the current carrying components of distribution systems, including cables, wires, busways, and overhead transmission lines, detailing their characteristics and installation conditions. Cables are used in both medium voltage (MV) and low voltage (LV) parts, while wires are simpler and deliver current to final loads. Busways are advantageous for long distances and future load additions but are limited by their high cost, while overhead lines are used in rural areas where underground installation is challenging.

2.  The Current Carrying Components Of The Distribution
System:
 Cables
 Wires
 Busways
 Overhead Transmission Lines

3.  They are the different types of electric conductors which
link between the different components of the distribution
system with all of its parts.
 These types of conductors must be selected to be suitable
for the conditions of the installation and must be properly
sized to withstand the calculated values of current which
flow through it.
 The main four types of the current carrying components in
the distribution system are:
 Cables
 Wires
 Busways
 Overhead lines.

4.  Cables are electrical conductors with some special components which
make it suitable to withstand different values of current and different
conditions of installation like mechanical forces and temperature.
conductor
Conductor shield
Insulator
Insulator Shield
Filler
Steel wire
Armor
Outer Jacket

5.  Cables are used in MV part of the distribution system to connect
between the MV distributer and RMUs, also between RMUs and
transformers.
 Also cables are used in the LV part of the distribution system to connect
between the transformer and main distribution board (MDB) and also
between the different distribution boards and their downstream panels.
 The installation conditions of cables differ according to the place which
the cables exist.
 The outdoor installed cables are usually direct buried, the cables
entering substations may be installed inside trenches and generally the
indoor cables are installed on cable trays.

6.  Wires are another way to carry electric current with
relatively simpler structure than cables. It mainly consists of
an electric conductor covered by an insulator.
 Wires are generally used to deliver electric current from
branch panels to final loads (lighting fixtures, sockets…etc).
 Wires are usually installed inside conduits with different
materials according to the installation conditions (exposed
or embedded in concrete or walls).

7.  Busways are an alternative way of cables which is preferred in some
conditions of installation like long distances in high rise towers, long
horizontal distances in malls, other conditions like large number of load
centers or possibility of adding new loads in future.
 Busway consists of three main parts: electric conductors in the form of
busbars, insulating material between conductors and housing.

8.  One of the main advantages of busways is the ability to move, remove
or add loads using the plug-in units which are can be added to the
busway at the position of the loads.
 Another advantage of busways is the reduced required space
compared to cables.
 The high cost is one of the restrictions which limits the use of busways.

9.  Overhead transmission lines OTL are used in some cases to
connect between the MV distributer and the distribution
transformers instead of underground cables.
 OTL are suitable in rural areas where there are farms which are
difficult to extend underground cables through them.
 In this case, the distribution transformers will be pole mounted.