This document provides information on various types of cables based on their construction and use. It discusses cable types for electrical, telecom, fiber optic and other applications. It also describes the construction of different cable types like XLPE and covers aspects of cable installation like laying, jointing, testing and maintenance. Common cable accessories used are also explained.

1. CABLE AND LAYING
-B. Prasad
Chartered Engineer
amieclub@gmail.com

2. Cable cut view

3. TYPE OF CABLE BASEDON CONSTRUCTION
 Coaxial cable
 Mineral-insulated copper-clad cable
 Twinax cable
 Flexible cables
 Non-metallic sheathed cable (or nonmetallic building wire, NM, NM-
B)[1]
 Metallic sheathed cable (or armored cable, AC, or BX)[1]
 Multicore cable (consist of more than one wire and is covered by
cable jacket)
 Shielded cable
 Single cable (from time to time this name is used for wire)
 Twisted pair
 Twisting cable

4. Cable for electrical
 PVC cable upto 3.3KV
 XLPE cable upto 33KV
 LT and HT ABC cable
 Instrumentation cable
 Concentric core cable
 Flexible cable & wire
 FR/FRLS/LSOH cable
 Fire survival cable
 Under water cable

5. Elastomer
 Trailing cable
 Locomotive cables
 Ship wiring cable
 Wind mill cable/solar cable
 Welding cable
 Mining cable
 LFH cable and wire
 Fire survival cable
 EPR, Silicon, EVA cables

6. Telecom
 PIJF cable
 5-2400 pair
 Indoor telephone cable
 QUAD/PCM cable
 Optical fibre cable
 Armoured/duct/aerial
 Torpedo cable
 TOW cable
 Composite cable

7. Fiber-Optic Cable
Advantages:
 It operate at high speeds
 It has a large carrying capacity
 The signals can be transmitted further without being
strengthened.
 It is immune to interference caused by electromagnetic
noise such as radios, motors, or other nearby cables.
 It is cheaper to maintain.
 You do not have to worry about grounding1 the cable.
Disadvantages:
 The cable is more expensive than copper cables.
 It is difficult to install.

8. Construction of cable

9. Construction of XLPE

10. Construction of EHV XLPE single core

11. XLPE has replaced conventional cable

12. Insulating material
 PVC (Polyvinyl
Chloride)
 PE (Polyethylene)
 XLPE (Cross-Linked
Polyethylene)
 EPR (Ethylene
Propylene Rubber)
 LSF (Low smoke and
fume)
 Polytetrafluoroethylene
(PTFE)
 Thermoplastic
Rubber (TPR)
 Neoprene
(Polychloroprene)
 Styrene Butadiene
Rubber (SBR)
 Silicone
 Rubber
 Chlorosulfonated
Polyethylene (CSPE)

13. Junction bus
1. Electrical Junction Boxes
2. Wiring Junction Boxes
3. Electric Junction Boxes
4. Plastic Junction Boxes
5. Cable Junction Boxes
6. Plastic Electrical Junction
Boxes
7. Weather proof junction boxes
8. Flameproof junction boxes

14. Cable lug
 Material:
copper
&
aluminium
 Conductivity
:
 Copper
99.7%
iacs
 Aluminium
61.2%

15. Cable lug ---contd

16. Cable manufacturers
 Name of manufacturer Brand
1. N.C cable industries National
2. Evershine Electric Works ECKO
3. Electric Cable Industries ECI
4. Paragon Cable Company paragon
5. Surya Power Limited ALCAB
6. National insulated cable co. NICCO
7. Indian cable company INCAB
8. Aluminium industries limited ALIND
9. R.K Electrical KALINGA
10. Polycab Industries POLYCAB
11. Plaza Cable PLAZA
12. Empire Cable Industries EMPIRE
13. Hovels cable HAVELL
14. Cable corporation of India CCI
15. Kei Industries Limited KEI

17. Historical progress of cable technology

18. Historical voltage development in country

19. Indian and international
standard

20. Reduction in insulation thickness

21. Metallic sheath

22. Lead sheath construction

23. Electrical Resistivity
Material Resistivity (µΩ-
cm@20 deg.C)
Copper 1.724
Aluminium
2.826
Steel 13.8
Lead 21.4

24. Density of material

25. Importance of cable installation
 A poor installation creates unreliable service
 other agency my damage the cable.
 Telephone cable, communication cable,
water line, gas pipe line may get affected

26. Location of cabling
 Laying direct in ground
 In pipes,
 Closed or Open ducts,
 Cable trays and
 On surface of wall

27. Step of cable installation
 Route survey
 Permission
 Trial pits
 Pipe laying
 Material shifting, drum placement
 Trenching cable laying
 Bedding and tiling
 Backfilling
 Cable installation record
 tagging

28. Route survey
 Type of surface like footpath, PCC, RCC, soil
type
 Hazardous like tree roots, pillars, sever line,
drain, bus stop, water pipe, gas pipe
 Cable root passing from private property
 Cable root away from parallel running gas,
water pipe, communication cable etc
 Road crossing, over bridge, drain crossing

29. Trial pit
 Along the
proposed cable
root.
 Trial pit at the
interval of 15-20
meter

30. Permission
Before starting the excavation permission to be
taken
 Railways
 Traffic police and defence
 Forrest department
 Communication and gas authority
 Other service department if any

31. Digging
 To display “Men
at work”
 Don't damage
the other cable
 Least use of
pickaxe and
chisel
 Correct Depth
depending upon
voltage grade

32. Depth of cable
 LT cable (1.1KV) 0.75 m
 HT cable (11KV) 0.90 m
 HT cable (33KV) 1.20 m
 Sand - covered with 150 mm
 Width of the trench - 350 mm minimum
 Loop –approximate -3 meter each side

33. Minimum bending radius
Voltage
rating
PILC cable PVC & XLPE cable
KV Single core Multicore Single core Multicore
Upto 1.1 20D 15D 15D 12D
1.1 to 11 20D 15D 15D 15D
Above 11 25D 20D 20D 15D

34. Pipe laying
 if cable crossing the road, gate, railway track,
water line
 Type of pipe: GI, cemented, HDPE pipe
 Ends to be sealed to avoid choking, clogging.
 Standard depth of pipe: 1m across the road,
1.8 m across railway track.
 Standard size of pipe: 1.5 times of cable
 Spare pipe: for future expansion , Ends to be
sealed

35. Bedding
 Before and after cable laying and jointing work
is over a bedding of sieved earth or river bed
sand of 100 mm depth both below and above
the cable.
 Keep distance between two cable in single
trench.
 Avoid zig-zag

36. Cable under bed/on support

37. CABLE LAYING IN TRAY

38. Cable laying on rack

39. Tagging on cable

40. Use barricading tape

41. Cable handling

42. Cable handling tools
 Jack
 Roller
 Drum trailer
 Crimping
tool

43. Cable installation record
 Type of cable and its size
 Voltage level
 Cable no, drum no.
 Date
 Rout map, location of cable joint
 Installation test record like IR value,
HV test if any

44. Testing of cable installation
 Insulation resistance test
 High voltage test
 Continuity test
Value
 IR value : minimum 1M-ohm/KV
 HV test value : minimum 1KV/KV +1
for 5 minutes

45. Cable testing
Type test
Routine test
Pre-commissioning test
A) for new cable after installation
B) After repairing the breakdown

46. Insulation resistance test
Before jointing and after
jointingS
no.
Voltage Test voltage
New installation Old installation
Recorded
IR value
1 upto1.1KV 500 V dc for 1 min. 1.0KV dc for 1 min. 50MΩ
2 11KV 1.0KV dc for 1 min. 2.5KV dc for 1 min 200MΩ
3 33KV 2.5KV dc for 1 min. 5.0 KV dc for 1 min. 500MΩ
4 66KV 5.0 KV dc for 1 min. 5.0 KV dc for 1 min. 500MΩ

47. High voltage test value
Sr. Voltage level
of the cable
under test
Test voltage Observed leakage
current (maximum)
New
installation
Old
installation
New
installation
Old
installation
1 upto1.1KV 3KV 660V 0.5mA 2mA
2 11KV 18KV 6.5KV 0.5mA 2mA
3 33KV 60KV 19.5KV 0.5mA 2mA
4 66KV 115KV 38KV 0.5mA 2mA

48. Cable testing at manufacturer’s works
 a) Tensile Test (For Aluminium Conductor)
 b) Wrapping Test (For Aluminium Conductor)
 c) Annealing Test (For Copper Conductor)
 d) Conductor Resistance Test
 e) Test for thickness of Insulation & Sheath
 f) High Voltage Test
 g) Insulation Resistance Test
 h) Tensile Strength & Elongation at break test for
 Insulation and Sheath
 I) Hot Set Test - (for XLPE Insulation only)
 j) Partial Discharge test (for H.T. Screened cable)

49. Cable short circuit
 ISC = kA /√t
 K= Constant
 Al -- 0.094 (XLPE)
 Cu -- 0.14382 (XLPE)
 A - Cross Section Area (mm 2
)
 T- Time in seconds

50. Earthing
 Metal screen
(if any) and
armour of
cable to be
earthed.
 All metal
pipes in which
cables have
been installed
need to be
earthed.

51. Corrosion Types Encountered With Power Cables
 Anodic Corrosion (Stray
DC Currents)
 Cathodic Corrosion
 Galvanic Corrosion
 Chemical Corrosion
 AC Corrosion
 Local Cell Corrosion
 Other Forms of
Corrosion

52. Voltage drop calculation
 For DC and single phase AC two wire
systems
 Voltage drop = (2xIxLxRxt)/1000
 Where I = current in ampere
 L = length of cable in meter (one conductor
only)
 R = resistance of one conductor from table
 t = temperature correction factor

53. Voltage drop ----contd
 For three phase AC systems
 Voltage drop = (1.732xIxLxRxt)/1000
 Note: formula is applied when power factor is
unity. Power factor to be considered in load and
reactance to be considered.
Note:
 formula is applied when power factor is unity.
Power factor to be considered in load and
reactance to be considered.

54. Resistance

55. Voltage drop value in%

56. Failure in cable
 Internal and surface discharge may result failure of
the insulation.
 Proper drying, due to low /bad quality of fluid.
 Ingress of moisture and degradation of insulation.
 Crack in the sheath, due to abnormal temperature,
electrical stress, mechanical tension.
 Voids due to partial discharge.
 Overheating, deformation, ionization etc.
 NB: permitted size of voids in cable to be 22-25
micron.

57. Root marker
 Aluminium
 Cast Iron
Material with
Standard or
Custom design
 Fibreglass
Reinforced
Plastic [FRP]

58. Cable tape
 Size:
 Length: 5Y, 5m,
10Y, 10m, 20Y,
20m.
 Width: 12mm,
15mm. 17mm,
18mm, 19mm,
25mm, 48mm,
50mm.

59. Cable gland
 Type of Cable
 Gland Size
 Entry Type/Thread
Specification of
application
 Ingress Protection
required.
 Material

60. Parts of gland

61. Type of Gland
 A1 and A2 Type Cable
Gland
 BW Type Cable Gland
 CW Type Cable Gland
 Single Compression
Cable Gland
 Double Compression
Cable Gland
 Flameproof Cable
Glands
 E1W Type Cable Gland
 Flange Type Cable
Gland
 PG Type Cable Gland
 Marine Type Cable
Gland
 Metric Threaded Cable
Gland
 Weather Proof Cable
Glands

62. Cable ties material
 Nylon 66
 Nylon 66 UV Stabilized
 Nylon 66 Heat Stabilized
 Polypropylene
 Tefzel

63. DIN rail and terminal block

64. De-rating factor
 Thermal insulation factors
 Ambient temperature
 Group factor
 Depth of laying
 Thermal resistivity
Depth of laying
(cm)
75 90 105 120 150 180
Cable size < 25
sqmm
1 0.99 0.98 0.97 0.96 0.95
Cable size < 300
sqmm
1 0.98 0.97 0.96 0.94 0.93
Cable size ≥ 300
sqmm
1 0.97 0.96 0.95 0.92 0.91

65. Busbar
Material :
 Aluminium
 Copper
Technical specification
 Rating Current:3200Amp.
 System:415Vac, TPN,
50Hz.
 Fault Level:50KA. For 1
Sec.
 Operation Temp:40° C
rise over 45 ° C ambient

66. Cable entry
 Indoor application:Top and bottom both
 Outdoor application: Only bottom

67. Conduit Fittings & Accessories
 Construction:
Galvanized steel,
helically wound, Flexible
Conduit System.
 Temp: -50 C to +200 C
 Features: Highly
Flexible and mechanical
strength
 IP: IP4

68. ACT FAST AND INITIATE
FIRST
 बड़ा सोचो
 तेजी से सोचो व
 सबसे पहले सोचो
 िवचारो पर िकसी का
 एकािधकार नही होता.
---- धीरभाई अमबानी

69. THANK
YOU