This document provides an overview of low voltage power cables. It discusses cable design principles including voltage ratings, conductor materials and sizes, insulation types, core identification, assembly processes, bedding, armoring, sheathing, and relevant standards. The key points are that low voltage cables operate between 300/500V and 600/1000V, use copper or aluminum conductors, and common insulation materials are PVC, XLPE, and EPR. Cores are typically identified by color and the document outlines the assembly, bedding, armoring, and sheathing processes. Finally, common international and national standards for low voltage cables are listed.

2. Course Scope
It covers all types of power cables, from
wiring and flexible cables for general
use to distribution, and transmission. It
includes information on materials,
design principles, installation and
standards, and it contains extensive
tables of data on commonly used cable
types.

3. Voltage – Current - Resistance

4. Ohm’s Law

5. Conductivity

6. Resistivity

7. Voltage :-
 Any electric equipment is denoted by its operating
voltage , cables are denoted as U0/UKV where :_
 Uo :- is the rated power frequency voltage between
conductor and earth or metallic screen for which cable
is designed.
 U : is the rated power frequency voltage between
conductors for which the cable is designed

8.  For example : Saying 0.6/1 (1.2) Kv cable means that
 Uo (Phase voltage) = 0.6 Kv
 U ( Line voltage) = 1 Kv
 Cable is defined by its line voltage as when saying 15
kv cables we mean 8.7/15 Kv

9. IEC Voltages
 45 KV
 66 KV
 110 KV
 132 KV
 150 KV
 220 KV
 275 KV
 330 KV
 400 KV
 500KV
 0.6/1 KV
 1.8/3 KV
 3.6/6 KV
 6/10 KV
 8.7/15 KV
 12/20 KV
 18/30 KV

10. Power cables
1- Overhead transmission lines
O.H.T.L

11.  Low voltage
2- Under ground power cables
 Medium voltage
 High voltage

14. Types of overhead conductors
1. ACC
( ALL CU. CONDUCTOR)

15. 2- AAC
 (ALL AL. CONDUTOR)

16. 3 – AAAC (ALL AL. ALLOY COND.)

17. 4 – ASCR (ALL ALLOY STEEL RIENFORCED)

18. 2) Comparison between O.H. conductors &U.G. cables:
O.H. CONDUCTOR U.G. CABLES
- Widely in transmission
Network & distribution net
work in urban areas
- Widely used in side towns where safety is requires
- Out door application - Both outdoor & Indoor (inside industrially residential &
Building, wiring & lighting application)
- Considered of less cost
compared with underground
cables
-Considered of higher cost compared with O.H conductors
Duration of an outage can be longer
since the failure tends to be more
difficult to locate and repair.
Duration of an outage is less .
Cable replacing due to load growth
is not easier. Therefore UGC should
be applied in areas where sharp load
growth would not be expected .
Conductor replacing is easier with some limits .
- Include processes of
1) Drawing section
2) Stranding section
- Includes processes of
1) Drawing section 6) Armoring section
2) Stranding section 7) Separation section
3) Insulation section 8) Lead section
4) Assembly section 9) Sheathing section
5) Bedding section

19. LOW VOLTAGE
CABLES

20. Voltage Grades of L.V. Cables:
 300/500 V [Both sheath & non-sheath cable (insulated
wires)]
 450/750 V [non-sheathed cables (insulated wires)]
 600/1000 V or 0.6/1 kV (Sheathed cables)

21. Material of Conductors
1) Copper:
Soft annealed copper conductor
2) Aluminum:
Aluminum conductor (H12)
- Copper has excellent electrical and mechanical
properties but it is more expensive than
Aluminum as it is cheaper and lighter .

22. Types & Shapes of Conductors
1) Solid round conductors
2) Flexible conductor
3) Stranded round conductor
4) Compacted round conductor
5) Sector shape conductor

23. Sizes of Conductors (mm2):
1.5 25 240
2 35 300
2.5 50 400
3 70 500
4 95 630
6 120 800
10 150 1000
16 185

24. Types of Insulation
 Poly Vinyl chloride ( PVC ) :
Thermo Plastic material
Maximum operating temp. is 70 °C
Maximum S.C. temp. 160 °C for C.S.A.  300mm2
Maximum S.C. temp. 140 °C for C.S.A. >300mm2
 Cross linked polyethylene ( XLPE ):
Thermosetting material
Maximum operating temp. is 90 °C
Maximum S.C. temp. 250 °C
 Ethylene propylene Rubber ( EPR ) :
Thermosetting material
Maximum operating temp. is 90 °C
Maximum S.C. temp. 250 °C

25. Cores Identification
Colors of cores are usually as following:
 Single core : Natural, Red, etc…
 2 cores : Red & Black
 3 cores : Red, Yellow & Blue
 4 cores : Red, Yellow, Blue & Black
 5 cores : Red, Yellow, Blue, Black & Green
 Grounding wire : Green & Green/Yellow
 More than 5 : (Black + No. or White + No. ,etc…)
Cores identification can be as per customer

26. Assembly Process
 The insulated cores assembly together with suitable lay
length (right hand).
 Polypropylene filler (if necessary) to fill the space
between cores to make the assembled shape round .
 Then wrapped with suitable tape to form a compact
round cable

27. Bedding Process
 The main function of the Bedding is to give
mechanical protection for insulation in case of
armored cables only.
 Material :
Extruded poly vinyl chloride ( PVC ) when there is
higher mechanical hazard we use polyethylene ( PE )

28. Armouring Process
 The Armouring is used as mechanical
protection for direct burial cables.
 It is used as an earthing conductor in some
Networks .

29.  Material :
The steel is the suitable material for multi-core cables
Steel is applied in one of the following forms :
 a) Tapes : Double tapes are applied helically
 around the bedding of cables with 50 % gap.
 b) Wires : Number of wires with the specified
diameter is to cover the bedding surface helically .
 In case of single core cables steel is replaced with non magnetic
material like Aluminum to reduce the magnetic losses (eddy current) .
Armouring Process

30. Sheath Process
 It is outer jacket of the cable , its main function is mechanical
protection.
 Material :
Poly Vinyl Chloride (PVC) , When there is higher mechanical
hazard we can use Polyethylene (PE)
 colour: Black or as per customer requirements
 Special characteristics may be included such as:
Anti-Termite resistant
Oil resistant
Chemical resistant
Acids & Alkaline resistant … etc.

31. In case of mechanical hazard we can use
polyethylene materials such as
 High Density Polyethylene [HDPE]
 Medium Density Polyethylene [MDPE]
 Linear Low Density Polyethylene [LLDPE]

32. STANDARDS
 IEC :International Electro technical commission
 BS : British standard institution
 VDE : Verband Deutshcke Electroteche
 NEMA : National Electrical Manufactures association
 UL : Under writer Laboratory
 ICEA : Insulated cable Engineers Association
 HD : Harmonised Document

33. STANDARDS
 IEC 60227 : Polyvinyl chloride insulated cables of rated voltage up to and
including 450/750 V
 IEC 60228 : Conductors of insulated cables.
 IEC 60502-1 : Cables for rated voltages of 1Kv (( Um =1.2 kV ) and
3 kV (Um =3.6kV)
 BS 6004 : Electric cables - PVC insulated, non-armoured cables for
voltages up to and including 450/750 V, for electric power,
lighting and internal wiring
 BS 7889 : Electric cables - Thermosetting insulated, un-armoured
cables for a voltage of 600/1000 V
 BS 6346 : 600/1000 V and 1900/3300 V armoured electric cables having
PVC insulation.
 BS 5467 : 600/1000 V and 1900/3300 V armoured electric cables having
thermosetting insulation.

34. SPECIFICATION
 Standard
 Type of conductor
 Size of conductor
 Number of cores
 Description (CU/XLPE/SWA/PVC)
 Customer special requirement