इंटरनेट
मानक
Disclosure to Promote the Right To Information
Whereas the Parliament of India has set out to provide a practical regime of right to
information for citizens to secure access to information under the control of public authorities,
in order to promote transparency and accountability in the working of every public authority,
and whereas the attached publication of the Bureau of Indian Standards is of particular interest
to the public, particularly disadvantaged communities and those engaged in the pursuit of
education and knowledge, the attached public safety standard is made available to promote the
timely dissemination of this information in an accurate manner to the public.
“जान1 का अ+धकार, जी1 का अ+धकार”
“प0रा1 को छोड न' 5 तरफ”
“The Right to Information, The Right to Live”
“Step Out From the Old to the New”
Mazdoor Kisan Shakti Sangathan
Jawaharlal Nehru
IS 14255 (1995): Aerial Bunched Cables for working
voltagess upto and including 1100 Volts [ETD 9: Power
Cables]
“!ान $ एक न' भारत का +नम-ण”
Satyanarayan Gangaram Pitroda
“Invent a New India Using Knowledge”
“!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता ह”
है”
ह
Bhartṛhari—Nītiśatakam
“Knowledge is such a treasure which cannot be stolen”
IS14255:1995
( Reaffirmed 2005 )
Indian Standard
AERTALBUNCHEDCABLES-FORWORKING
VOLTAGESUPTOANDINCLUDING
1 lOOVOLTS -SPECIFICATION
UDC
621.315211
( 621-315.616-96
Q
BUREAU
MANAK
April
1995
OF
BHAVAN,
) : 621-396.67
BIS 1995
INDIAN
STANDARDS
9 BAHADUR
SHAH
NEW DELHI 110002
ZAFAR
MARG
Price Group 4
Power
Cables
Sectional
Committee,
ETD 9
FOREWORD
This Indian Standard
was adopted
Power Cables Sectional
Committee
by the Bureau of Indian Standards,
after the draft finalized
by
had been approved by the Electrotechnical
Division
Council.
the
This standard
specifies the requirement
of Polyethylene/crosslinked
polyethylene
insulated
cables with
aluminium
conductors
twisted over a central bare/Insulated
aluminium
alloy messenger wire for use as
overhead distribution
feeders for rated voltages up to and including
1 100 V.
Many countries
are now increasingly
using cables with insulated
conductor
This system is commonly
called ABC system ( Aerial Bunched Cables ).
for
LT
overhead
lines.
In the ABC system, the insulated
conductors
( 3 or 4 numbers as required ) are twisted
around
a high
strength aluminium
alloy bearer wire, which carries the main weight and also serves as the earth-cumneutral wire. The bearer wire ( messenger
) may be bare or insulated.
The phase
conductors
are not
under tension.
The system is very safe and LT faults are practically
eliminated
Consequently,
interruptions
of supply
are minimized
and the life of transformers
is considerably
increased
as these are not subjected
to
frequent
faults
as happens
with the bare
conductors.
The problem
of tree clearance
is also
minimized.
For the purpose of deciding whether
a particular
requirement
of this standard
is complied
with, the
final value,
observed or calculated,
expressing the result of a test, shall be rounded off in accordance
places
with IS 2 : 1960 $Rules for rounding
off numerical
values ( revised )‘. The number of significant
retained
in the rounded off value should be the same as that of the specified value in thts standard.
IS 14255 : 1995
Indian Standard
AERIAL BUNCHED CABLES - FOR WORKING
VOLTAGES UP TO AND INCLUDINS;
1 100 VOLTS - SPECIFICATION
SECTION 1 GENERAL
definitions, in addition to those given
(Part 32) : 1993 shall apply.
1 SCOPE
3.1 Routine Tests
1.1 This slaudard
covers the requiremruts
01
insulated
polyethylenc/c~rossli~~ked
polyethyleur
cables with aluminium
conductors twisted over a
central bare/insulated aluminium alloy messenger wire
for use as overhead distribution feeders.
Tests made by the manufacturers on all finished cable
leugths to demoustrate the integrity of the cables.
3.2 Type Test
Tests required to be made before supply OII a geueral
commercial basis ou a type of cable in order to
demonstrate satisfactory performance characteristics to
meet the intended application.
1.2 The cables covered in this standard are suitable for
use on three phase ac (earthed or unearthed) system for
rated voltage up to and including 1 100 V.
NOTE-The
cables conforming to this standard may be
operated continuously at a power frequency voltage 10
percent higher than the rated voltage.
NOTEThese tests are of such a nature that after they
have been made, they need nothe repeated unless changes
are made in the cable materials or design which might
change the performance characteristics.
1.3 The cables covered in this standard are suitable for
use where the combination of ambient temperature and
temperature rise due to load, including temperature ou
exposure to direct smllight results in conductor
temperature not exceeding the following:
TyVe of
lnsrtl~~tion
Normal Contimdous
Opercztion
in IS 1885
3.3 Acceptance
Tests
Tests carried out ou samples taken from a lot for the.
purpose of acceptance of the lot.
Short Circuit
Oprcition
3.4 Optional
Tests
Polyethylene
70°C
160’C
Crosslinked
polyethylene
Special tests to be carried out, wheu required by
agreement behveeu the purchaser and the supplier.
90°C
2XJ°C
3.5 Earthed
2 REFERENCES
2.1 The following Indian
adjuncts to this standard:
IS No.
398 (Part 4) :
1979
Staudards
Almninium
conductors for overhead transmissiou purposes : Part 4
Almninium alloy stranded conductors
(aluminium-magnesimnsilicon type) (second mvision)
x130 : 1984
Conductors for insulated electric cables
and flexible cords (Frst revision)
10418:
Drums for electric cables
10810 (series)
a>The
me
Electrotechnical vocabulary : Part 32
Electric cables Cfirst revision)
1982
An electric system which fultills auy of the following
conditions:
are necessary
1885 (Part 32) :
1993
b)
4
Methods of test for cables. (The
relevant part numbers are given iu
col 4 of 10.1)
neutral point or mid fioint connectiou is
earthed iu such a manlier that even under fault
conditions,
the maximum voltage that can
occur between any conductor and earth does
not exceed 80 percent of the nominal system
voltage;
The Deutral point or mid point comiectiou is
not earthed but a protective device is installed
which automatically
cuts out any part of the
system which accidentally becomes earthed;
or
In case of ac system oidy, the neutral point is
earthed through an arc suppression coil with
arraugemeut
for isolation within 1 hour of
occurrence of the fault provided that total of
such periods in a year does not exceed 125 hours.
3.6 Unearthed System
3 TERMINOLOGY
3.0
System
AII electric system which does not fulfil the requirements of earthed system (see 3.5).
For the purpose of this standard the following
1
IS 14255:
I995
SECTION
ncsium-
silicon
alloy wires containing approximate 0.5
perc’~nl magnrhium
and approximately
0.5
pcrccnl
silicon conli,rming
to IS 39X (Part 4) : 1979).
2 MATERIALS
4 (:ONI)ll(“I‘OH
4.1 I’h;~se/Strect I,ighting (conductor
The colductor shall hc 01‘ H2 or H4
~ontplying
will1
lhc
rrquircn~cuL\
4.2 Messenger (Neutral
The conductor
grade
5 INSIJIAI‘ION
aluminiutn
IS X130 : 10X4.
of
<Conductor or Otherwise)
shall he of heat
treated
St No.
5.1 Thr insulation
shall hc cithcr of’ cross-linkrd
polycthylrnc
co~npound or ot’polycthylcnr
conq~ound,
conforming
to requircmcnt
given in Tahlrs
I and Z
rcspcclivcly.
alumi~~iun~-taag-
Hequimmenl.5
‘fed.5
(1)
(3)
(2)
i)
Tensile strength
12.5 N/mm’,
ii)
IJlongation
200
iii)
Agcing
at
break
: I‘emperafure
Ihration
‘l‘ensile strength variation
c)Elongation variation
iv)
Treatment
: ‘I’emperature
200 * 3Y’
1.5 min
Mechanical stress
20 N/cm’
175 percent, MUX
c) Permanent elongation (set) after cooling
15 percent, Mus
Shrinkage:
: Temperature
130 * 3?’
1 hour
4 percent, MUX
II) Shrinkage
Water absorption (Gravimetric):
a) Treatment
: Iemperature
Duration
h) Water ahsorbed
viii)
Max
~2.5 perccn t , Max
‘lime under load
Duration
vii)
i2.5 percent,
h) Elongation under load
a) Treatment
vi)
135 f 3°C
7 days
f lot set:
a)
v)
Min
Min
in air oven:
a) Treatment
h)
peramt,
8.5 * 2?‘
14 days
I mg/cm2, MUX
Volume resistivity:
a) at 27°C’
1x
I>) ilt 7tPC’
1 x 10” ohm-cm, Min
(.‘arbon blilck:
a) (‘onten
h) Dispersion
IO’”
ohm-cm, Min
Under consideration
IS 14255 : 1995
Table 2 Properties
of PE Insulation
(Clause 5.1)
SI No.
Requirements
Property
Volume resistivity:
i)
a) at 27Y
1 x 1014 ohm-cm f Min
b) at 70°C
1 x 1OL2ohm-cm 9Min
ii)
Tensile strength
lO.N/mm’,
Min
iii)
Elongation at break
300 percent, Min
iv)
Melt flow index
3,Mrrr
v)
Wcat softening point
8S°C, Min
vi)
Carbon black:
vii)
a) Content
Under consideration
b) Dispersion
Under consideration
No cracks shall be visible to naked eye
Environmental stress cracking
6.4
SECTION 3 CONSTRUCTION
The
size
of
street
lighting
conductor
shall
be 16 trim*.
6.5 The size of messettger cottductor and its breaking
6.1 The power/outer insulated neutral/street lighting
cottductors shall cottform to flexibility
class 2 of
IS 8130 : 1984.
6.2 The messettger (Neutral conductor) or otherwise
shall be either stranded circular or cotnpacted circular
type and shall have tnittitttum 7 strands. The surface of
the conductor shall be smooth.
6.3 ‘A protective barrier may be applied between the
cottductor and ittsttlatiott, if required. Such barrier,
whett used, shall be cotnpatible with itisulating material
and suitable for the operating tetnperature of the cable.
Table 3 Size and Reqtthments
load shall be as per Table 3.
6.6 There shall be no joittts in atty wire of the messenger conductor except those tnade in the base rod or
wires before fntal drawing. The directiott of outer layer of
wires in ntessettger conductor shall be right hand.
7 INSULATION
7.1 The cottductor (with protective
barrier, wherever
with
crosslinked
shall
be provided
applied)
polyethylene
or polyethylette
ittsulatiott applied by
extrttsiott.
of Messenger
Cottductor
(Clause 6.5)
SI No.
Nominal Cross Sectional
Messenger Conductor
Area
of Phase
Conductor
Sectional Area
Maximum dc Resistance
at 20°C
Minimum Breaking
Load
mm2
mm*
ohm/km
kN
(1)
9
(2)
16
(3)
(4)
(5)
25
i .38
7.0
ii)
25
25
1.38
7.0
3.5
25
1.38
7.0
50
35
0.986
9.8
v)
70
50
0.689
14.0
vi)
95
70
0 492
19.7
iii)
iv)
Nominal Cross
IS 14255 : 1995
7.2 Thickness
of Insulation
7.4 Application
The average
thickness of insulation shall be not less
than the nomiual value (t;) specified in Table 4.
Table 4 Thickness
of Insulation
of Insulatiou
The insulation shall be so applied that it fits closely on
the conductor (or barrier, if any) and it shall be possible
to remove it without damaging the conductor.
7.5 The colour of insulation shall be black.
8 COKE II)ENTIFI’I(:ATION
Nominal Area of
Nominal Thickness (ti)
8.1 Tbe phase conductors shall be provided with one,
(‘onductor
rImI*
mm
(‘1
16
(2)
1.2
25
1.2
35
1.2
50
1.5
70
1.5
9s
1.5
7.3 Tolerosce
on Thickness
two or three ‘ridges’ and outer neutral insulated conductor, if provided, shall have four ‘ridges’ as shown iu
Fig. 1 for quick identification. The street lighting conductor and messenger conductor (if insulated) shall not
have any identilication mark.
8.2 Identification by other means, as agreed between
the supplier and purchaseer, is also permissible.
9 ASSEMBLY (LAYING III’)
9.1 Three insulated phase couductors, one insulated
neutral conductor (if required) and a street lighting
conductor (if required) shall be twisted around the bare
(or insulated) as required messenger conductor without
fillers with a lay not exceeding 3.5 times the diameter
of the insulated phase conductor.
of Insulation
of measured values of thickness ofinsulation shall not fall below the nominal value (li) specitied
in Table 4 by more than 0.1 mm + 0.1 (ri).
The +~allest
9.2 The direction of lay shall be right hand.
ORS
NEUTRAL
CONDUCTOR
F1cr.1 CORE IDENTIFICATTON
4
3
IS 14255 : 1995
10.1 Type Tests
SECTION 4 TESTS
10 CLASSIFICATION
OF TESTS
SI
The following
Tests
shall constitute
Requirements
Test Method
(Ref to Part No. of
IS 10810)
No.
(2)
(1)
a)
(3)
i) Tensile test
See IS 8130
test
iii) Resistance test
: 1984
2
do
3
do
5
Test on messenger conductor:
i) Breaking
load
ii) Elongation
test
iii) Resistance test
c)
(4)
Tests on phase/street light conductor:
ii) Wrapping
b)
type tests:
Physical tests for XLPE
2
see 11.3
11.3
See Table 3
5
Set Table 1
7
Insulation:
i) Tensile strength and elongation
at break
ii) Ageing in air oven
iii) Hot set test
iv) .Shrinkage test
v) Water ahsorption
See Table 3
(Gmvimetric)
do
11
do
30
do
12
do
33
vi) <hrbon black:
Under consideration
1) Content
2) Dispersion
d)
Physical test for PE insulation:
i) Tensile strength and elongation
at break
ii) Melt flow index
See Table 2
7
do
23
do
32
iii) Carbon black:
1) Content
2) Dispersion
do
Under consideration
iv) Vicat softening
point
do
22
v) Environmental
stress cracking
do
29
e)
Test for thickness insulation
f)
Insulation
g)
High voltage test
resistance (Volume resistivity)
See Table 4
test
See Table
1 and 2
See 11.2
8
43
45
IS 14255 : 1995
disregarded aud auother test made.
10.2 Acceptance Test
The following shall coustitute acceptaure
a)
b)
4
4
tests:
Tensile test (for phase/street light conductor),
The elongation of the specimen shall be not less thau 4
percent on a gauge length of 200 nun.
11.4 Bending Test on the Completed
Wrapping test (for phase/street light conductor),
Breakiug load test for messenger conductor,
Elougatiou test for nlesseuger conductor,
e>
CT,uductor resistauce test,
f-J Test for thickness of hsulatiou,
g) Tensile strength and elougatiou at break
h) Hot set test for XLPE insulation,
j) Insulation resistance test, aud
k) High voltage test.
10.2.1 A. reconnnended sampling
tests is given in Annex A.
10.3 Routine
test,
Cable
The test shall be performed ou a sample of complete
cable. The sample shall be bent around a test mandrel
at roonl teulyeraturr for at least one coinplete turn. It
shall then be unwound aud the process shall be repeated
after turuing the salnyle around its axis by 180 degrees.
The cycle of these operatious shall theu be repeated
twice. The diauleter of the mandrel shall be :
lO(D+d)
where
D = actual diauleter of the cable, for example,
nlininunu circuulscribiug diameter, nun; and
plan for acceptance
d = actual diauleter of the phase conductor, nun.
Requirelneut
allowed.
Tests
: No cracks visible to the naked eye are
The following shall constitute routiue tests:
a) Conductor resistance test, and
b) High voltage test.
10.4 Optional
SECTIQN 5 IDENTIFICATION,
AND MARKlNG
PACKING
Test
12 IDENTIFICATION
The following shall constitute optional test:
12.1 Manufacturers,
Bending test.
Identification
Unless otherwise stated in this standard, the tests shall
be carried out in accordance with appropriate parts of
IS 10810 taking into account additional information
given in this standard.
The nlanufacturer shall be identified throughout the
length of the cable by means of a tape bearing the
manufacturers
name or trade-mark
and year of
lnanufacture. In case the above inethod cannot be
employed, or if the purchaser so desires, colour
identiticatiou threads in accordance with a scheme
to be approved by the Bureau of Iudiau Staudards (BIS)
shall be employed.
11.2 High Voltage Test
12.2 Cable Identification
High voltage test at room temperature (Type, Acceptance and Routine Test ):
Cables with cross-linked polyethylene insulation shall
be identified throughout the length of the cable by the
legend ‘XLPE 90’ aud year of manufacture by a yriuted
tape. No identificatiou is required for polyethyleue
insulation.
11 DETAILS
OF TEST
11.1 General
The cable shall withstand a voltage of 3 kV ac (nns)
at a frequency of 40 to 60 Hz or a dc voltage of 7.2
kV between conductors for 5 minutes.
11.3 Elongation
Test on Messenger
NOTES
1 Single tape bearing manufacturer’s name or trademark and the cable identification, that is, XLPE 90, it’
Conductor
Test shall be carried out on wires before stranding. The
specimen shall be straightened
by baud and au
original gauge leugth of 200 nnn shall be marked ou the
wire. A teusile load shall be applied by nleaus of a suitable
tensile testing machine. The load shall be applied
gradually aud the rate of separation of the jaws of the
testing machine shall be not less than 25 nun per minute
and uot greater thau 100 nnn per minute. The elongation shall be measured after the fractured cuds have
been titted together. If the fracture occurs outside the
gauge marks, or withiu 25 nnn of either Inark, aud the
required elongatiou is not obtained, the test shall be
provided, shall be acceptable against the requirement
of 12.1 and 12.2.
2 Identitication required in 12.1 and 12.2 shall be given
on any one of the insulated conductor of cal~les.
13 PACKING
AND MARKING
13.1 The cable shall be wouud ou a druui (see
IS 10418 : 1982) of suitable size aud packed. The euds
of the cable shall be sealed by non-hygroscopic
material.
13.2 The cable shall carry the following
6
infonnatiou
IS 14255 : 1995
either stencilled
attached to it:
on the drum or contained
in a label
a>Referettce
b)
Cl
4
e)
q
g)
h)
j)
to this Ittdiatt Standard, for example,
Ref IS 14255 ;
Mattufachtrer’s ttattte or trade-tttark;
Type of cable and voltage grade;
Notttittal cross-sectiottal area of phase cottductor;
Length of cable ou the drum;
Nutttber oflettgtlts on the druttt (if more than otte);
Directiott of rotatiott of drum (by ttteatts of att
arrow);
Gross mass;
Coutttry of tnattufacture; attd
k) Year of manufacture.
13.2.1 The cable (drum or label) , may. also he marked
with the Standard &4ark.
NOTE -The
use of the Standard Mark is governed by
the provisionsof
Hureauoflndian
Standards Act, 1986
and the Rules and Regulations made thereunder. The
details of conditions under which the license for the use
of Standard Mark may he granted to manufacturers or
producers may he obtained from the Bureau of Indian
Standards.
SECTION 6 ACCESSORIES FOR AERIAL
BUNCHED CABLES
14 The accessories which are in cottttnott use for aerial
buttched cables are uttdrr consideration.
ANNEXA
(Clause
10.2.1)
SAMPLING
A-l
LOT
A-l.1
In any consignment the cables of the sattte size
tttattufactured uttder essetttially sitttilar conditions of
yroductiott shall be grouped together to cottstitute a lot.
A-2 SCALE
OF SAMPLING
A-2.1 Samples shall be taken attd tested frottt each lot
for ascertaining the cottfortnity of the lot to the requiretnettts of the specification.
A-2.2 The ttutnber of drutns (n) to be selected from the
lot of drums (N) of cottsigmnent of cables shall be itt
accordance with col 2 and 1 of Table 5 respectively.
These satnples shall be takett at random.
A-2.2.1 In order to ettsure the rattdotnttess of selection,
rattdom nutnber tables shall be used (see IS 4905 : 1968
Methods of rattdom sampling).
A-3 NUMBER OFTESTS
CONFORMITY
ANI) CRITERION
FOR
A-3.1 Suitable lettgth of test sample shall be taken from
each of the drutns selected. These test samples shall be
subjected to each of the acceptattce tests (see 10.2). A
OF CABLES
test sample is called defective if it fails itt any of the
acceptance tests. If the ttutttber of defectives is less than
or equal to the correspottdittg permissible ttumber (a)
givett in co1 3 of Table 5 the lot shall be declared as
conforming to the requirements of acceptattce test,
othetwise not.
Table 5 Number of Drums to be Selected for
Sampling and Permissible
Number of Defectives
Number of
Drums in
the Lot
Number of
Drums tu be
Taken as
Sample
Permissible
Number of
Defectives
(1)
(2)
n
(3)
2
0
N
up to 50
a
5
0
101 “300
13
0
301 “500
20
501 and ahove
32
51 to 100
r(
L
Bureau of Iodian Standards
51s is a statutory
institution
established
under
the Bureau of Indian Standards Act, 1986 to promote
harmonious
development
of the activities of standardtzation,
marking and quality certification
of goociz
and attending
to connected
matters in the country.
Copyright
BIS has the copyright
of all its publications.
No part of these publications
may be reproduced
in any
form without the prior permission
in writing of BIS. This does not preclude the free use, in the course
of implementing
the standard,
of necessary
details,
such as symbols
and sizes,
type or grade
designations.
Enquiries
relating to copyright be addressed
to the Director
( Publications
), BIS.
Review of Indian Standards
Amendments
are issued to standards as the need arises on the basis of comments.
Standards
are also
reviewed periodically;
a standard along with amendments
is reaffirmed when such review indicates
that
no changes are needed;
if the review indicates
that changes are needed,
it is taken
up for revision.
Users of Indian
Standards
should ascertain
that they are in possession
of the latest
amendments
or
edition.
This Indian
Standard
has been developed
from Dot
Amendments
Amend
Issued Since Publication
Date
No.
No. ETD 09 (3478).
Text Affected
of Issue
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