Internati
o
nal
Journal of Ele
c
trical
and Computer
Engineering
(IJE
CE)
V
o
l.
6, N
o
. 1
,
Febr
u
a
r
y
201
6,
pp
. 34
~39
I
S
SN
: 208
8-8
7
0
8
,
D
O
I
:
10.115
91
/ij
ece.v6
i
1.8
391
34
Jo
urn
a
l
h
o
me
pa
ge
: h
ttp
://iaesjo
u
r
na
l.com/
o
n
lin
e/ind
e
x.ph
p
/
IJECE
An Effective Cable Sizing Proce
dure Model for Industries and
Commerial Buildings
M
.
Prat
ap N
a
i
r
*
,
K. N
i
thiyana
n
t
h
a
n
+
* Faculty
of
Eng
i
neer
ing and
Co
mputer Technolog
y
,
AIMST Un
iversity
Bedong, Kedah
,
Malay
s
ia
+
Departm
e
nt of
Ele
c
tri
cal
and
E
l
ectron
i
cs
Eng
i
ne
ering,
Karpag
am
Coll
ege o
f
Eng
i
neering
,
Co
im
batore,
India
Article Info
A
B
STRAC
T
Article histo
r
y:
Received
J
u
l 19, 2015
Rev
i
sed
O
c
t 30
, 20
15
Accepted Nov 12, 2015
This paper mainly
fo
cuses on the cab
le
sizing
methods and calculation o
f
ele
c
tri
cal c
a
bl
e
s
according to
the various
interna
tiona
l s
t
a
ndards
.
F
o
r
instanc
e
, In
ter
n
ation
a
l E
l
ec
tr
otechn
i
ca
l Co
m
m
i
ssion (IEC), Nation
a
l
Ele
c
tri
cal
Code
(NEC), Bri
tish
Standard (BS)
a
nd Institut
e
of
E
l
ec
tric
al
and
Electronics Eng
i
neers (IEEE)
.
The ba
sic philo
soph
y
under
l
y
i
n
g
an
y
cab
le
s
i
zing ca
lcul
atio
ns
are the s
a
m
e
.
The m
a
in objec
tive of this
res
e
a
r
ch work is
to dev
e
lop
effe
ct
ive
cabl
e
si
zing
m
odel for bu
ildi
ng servic
es.
Keyword:
Am
p
acity
Cable sizing
Co
ndu
cto
r
Current ca
rrying ca
pacity
Vol
t
a
ge
d
r
op
Copyright ©
201
6 Institut
e
o
f
Ad
vanced
Engin
eer
ing and S
c
i
e
nce.
All rights re
se
rve
d
.
Co
rresp
ond
i
ng
Autho
r
:
K. Nith
iyan
an
th
an,
Depa
rt
m
e
nt
of
El
ect
ri
cal
and
El
ect
roni
cs
E
n
gi
nee
r
i
n
g,
Kar
p
a
g
am
C
o
l
l
ege
of
En
gi
ne
e
r
i
n
g, C
o
i
m
bat
o
re,
In
di
a
Em
a
il: n
ith
iiee
e
@yaho
o
.co.in
1.
INTRODUCTION
There
are
four prim
ary reas
on
s t
h
at th
e cab
le sizing
is
very im
port
a
nt
at
desi
g
n
st
ag
e.
Fi
rst
an
d
forem
o
st, cable sizing is im
portan
t to function endlessly unde
r full lo
ad c
o
ndition exclusive
of bei
ng
d
a
m
a
g
e
d
.
Mo
reo
v
e
r, it is n
ecessary to
ho
ld
up
th
e wo
rst sh
o
r
t circu
it cu
rren
t
flow
an
d
en
su
re that th
e
protective devi
ces
are
e
ffecti
v
e during
a
n
earth fault.
Ensu
re th
at, the
su
pp
ly to
t
h
e
lo
ad
with
a suitab
l
e
vol
t
a
ge
an
d av
oi
d
e
x
cessi
ve v
o
l
t
a
ge dr
o
p
s.
2.
CABLE SEL
E
CTION, SIZING
AND OT
HER PARAMETERS
Si
zi
ng C
a
bl
e s
i
zi
ng m
e
t
hods
fol
l
o
w t
h
e u
n
c
han
g
e
d
basi
c
st
ep pr
ocess.
Fi
rst
l
y
, i
t
’
s vi
t
a
l
t
o
gat
h
er
d
a
ta ab
ou
t th
e cab
les, in
stallatio
n
surrou
nd
i
n
g
s
, and
th
e load
th
at it will
c
a
rry. In
add
ition
,
it’s crucial t
o
find
t
h
e cu
rre
nt
car
ry
i
ng ca
paci
t
y
(A,
am
pere) a
n
d
vol
t
a
ge
d
r
o
p
per am
pere m
e
t
e
r (m
V/
A/m
)
of t
h
e ca
bl
e [
1
]
.
Th
e
current ca
rrying capacity of
a cable
is the maxim
u
m
current
that can fl
ow c
o
ntin
uou
sly th
r
o
ugh
a cab
l
e
wi
t
h
o
u
t
dam
a
gi
ng t
h
e ca
bl
e'
s i
n
sul
a
t
i
o
n an
d
ot
her c
o
m
pon
ent
s
[
2
]
.
Sh
ort
ci
rcui
t
t
e
m
p
erat
ure ri
se a
nd
eart
h
fau
lt loop
im
p
e
d
a
n
c
e are sign
i
f
ican
t
fa
ctors t
o
verify t
h
e ca
ble size.
Each c
o
nd
uct
o
rs a
n
d
ca
bl
es e
x
cept
su
pe
rco
n
duct
o
r
ha
ve
so
m
e
am
ount
o
f
resi
st
ance.
T
h
i
s
resi
st
a
n
ce
is d
i
rectly propo
rtion
a
l to th
e l
e
n
g
t
h
an
d inv
e
rsel
y pr
opo
r
tion
a
l to
t
h
e
d
i
ameter
of
th
e co
nd
u
c
t
o
r.
R
α
L/a
[Laws
of
resist
ance R =
ρ
(L/
a
)]
[1]
Evaluation Warning : The document was created with Spire.PDF for Python.
I
S
SN
:
2
088
-87
08
I
J
ECE Vo
l. 6
,
N
o
. 1
,
Febru
a
ry
2
016
: 3
4
–
39
35
Vo
ltag
e
d
r
op
o
ccurs in
ev
ery co
n
d
u
c
t
o
r as th
e cu
rren
t fl
o
w
s t
h
ro
ugh
it. Accord
ing
to In
stitu
te of
Electrical and
Electronics E
n
gi
nee
r
s (
I
EEE
)
rul
e
B
-
23
, at
any
p
o
i
n
t
bet
w
een a
po
we
r
sup
p
l
y
t
e
rm
i
n
al
and
in
stallatio
n
,
v
o
ltag
e
dr
op
shou
ld
no
t in
cr
ease abo
v
e
2.5%
o
f
pr
ov
id
ed
(
s
up
p
l
y) vo
ltag
e
[3
].
Th
e cab
l
e should
w
ith
stan
d the te
m
p
er
atu
r
e
an
d h
eat emm
i
sio
n
w
ith
u
s
ing go
od
insu
lation
m
a
ter
i
al
s
suc
h
as c
o
nd
uc
t
o
rs,
an
d
be
ddi
ng
. Ta
bl
e
1 s
h
ows
t
h
e
cu
rre
n
t
carri
ed
by
a
n
y
con
d
u
ct
o
r
f
o
r c
ont
i
n
u
ous
p
e
ri
o
d
s
d
u
ring
no
rm
al
o
p
e
ration
sh
all b
e
su
ch
t
h
at the su
itab
l
e tem
p
eratu
r
e limits.
Tab
l
e
1
.
Max
i
m
u
m
o
p
e
ratin
g te
m
p
eratures
fo
r typ
e
s
o
f
cable in
su
lation
Type of insulatio
n
Te
m
p
e
r
ature
li
m
i
t
T
h
erm
oplastic
70°
C at the conductor
Therm
o
setting
90°C at the conductor
M
i
ner
a
l
70°
C at the sheath
and
m
o
r
e
C
a
bl
es wi
t
h
l
a
rge
r
c
r
os
s-sect
i
onal
a
r
eas
ha
ve m
i
nor
resist
iv
e lo
sses. Bi
gg
er cab
le ab
le
to
d
i
ssi
p
a
te
th
e heat b
e
tter
th
an
sm
aller one.
He
nce a
15 mm
2
cable wi
ll have
a
highe
r
c
u
rren
t carryin
g
cap
acity th
an
a 4
mm
2
cable. Table 2 explains
the
diffe
re
nce
be
t
w
een c
u
rre
nt
carry
i
n
g ca
pac
i
t
y
of
16
m
m
2
an
d
25
mm
2
.
Tabl
e
2. C
u
r
r
e
n
t
car
ry
i
n
g
ca
p
aci
t
y
and
vol
t
a
ge
dr
o
p
of
di
f
f
e
rent
t
y
pes
o
f
c
a
bl
e si
ze [
4
]
Cable size
Cur
r
e
nt-
carr
y
ing capacity
Voltage dr
op
≤
16
m
m
2
0.
95
1.
10
≥
25
m
m
2
0.
97
1.
06
Fi
gu
re
1.
Fl
o
w
cha
r
t
sh
o
w
s t
h
e st
eps t
o
det
e
r
m
i
n
e t
h
e ca
bl
e
si
zi
ng a
n
d
vol
t
a
ge
dr
o
p
Typ
e
of
Cab
l
e
Se
le
ct
suitab
le
cab
l
e
ty
p
e
fr
o
m
any
cable
m
a
nufac
t
u
rer
dt
h
t
Siz
e
of
cir
c
u
i
t
pr
ot
ectio
n
Adjust
Am
pac
i
t
y
Apply
vo
lt
a
g
e
dr
o
p
Fin
a
l
Ca
ble
size
Evaluation Warning : The document was created with Spire.PDF for Python.
IJECE
ISS
N
:
2088-8708
An Ef
f
ect
i
ve C
abl
e
Si
zi
n
g
P
r
o
ced
ure
Mo
del
f
o
r
In
d
u
st
ri
es
an
d C
o
m
m
eri
a
l
Bui
l
d
i
n
gs
(Dr. K. Nith
iyana
nth
a
n
)
36
3.
CABLE SEL
E
CTION SIZ
I
NG
FORMULAION
In
tern
ation
a
l stan
d
a
rd
s and
cab
le m
a
n
u
f
actu
rers will p
r
o
v
i
d
e
d
e
rating facto
r
s fo
r a rang
e
o
f
in
stallatio
n
con
d
ition
s
,
fo
r ex
am
p
l
e a
m
b
i
e
n
tor so
il te
m
p
eratu
r
e,
g
r
o
u
p
i
n
g
or
b
u
n
c
h
i
ng
o
f
cab
l
es, an
d so
i
l
th
erm
a
l resisti
v
ity. Th
e in
stal
led
cu
rren
t ratin
g
is calcu
lated
b
y
m
u
ltip
lyi
n
g
t
h
e b
a
se curren
t
ratin
g
with
each
of
t
h
e derat
i
ng
fact
or
s.
I
c
= I
b
x k
d
[2]
Whe
r
e I
c
is th
e in
stalled
cu
rren
t
ratin
g
(A), I
b
is th
e b
a
se c
u
rren
t rating
(A) and
K
d
are
th
e p
r
o
d
u
c
t of all th
e
derat
i
n
g fact
o
r
s.
Upst
ream
prot
ect
i
v
e devi
ce c
i
rcui
t
brea
ke
r i
s
not
re
q
u
ire
d
to protect the cable
against overloa
d
s. As
a resu
lt, cab
les n
e
ed
o
n
l
y to be sized
t
o
cater fo
r t
h
e
fu
ll lo
ad
cu
rren
t
of th
e m
o
to
r [5
].
I
l
≤
I
c
[3]
Whe
r
e I
l
is th
e
fu
ll lo
ad
curren
t
(A),
I
p
is th
e p
r
o
t
ectiv
e d
e
vice ratin
g
(A) I
c
is th
e in
stalle
d
cab
le cu
rren
t
rating
(A
).
Cable Im
pedances is a function of the cabl
e
size (c
ross
-s
ectional area)
and th
e leng
th o
f
th
e cab
le.
Most cable m
a
nufacturers
will quote
a cable
’s resistance a
nd
reactance in
Ω
/km
.
The fol
l
owing typical cable
i
m
p
e
d
a
n
ces
for low vo
ltag
e
AC sing
le core an
d
m
u
ltico
r
e
cab
les can
b
e
used
in
t
h
e absen
ce of an
y o
t
her d
a
ta
[6]
.
For single circ
uit
[
4
]
Whe
r
e t
h
e
protective de
vice
is is a se
m
i
enclosed fuse
to
BS 3036, C
f
=
0
.7
25
ot
her
w
i
s
e
C
f
=1
. Th
e
cabl
e
i
n
st
al
l
a
t
i
o
n
m
e
t
hod i
s
‘
i
n a
duct
i
n
t
h
e g
r
o
u
n
d
’
or
‘
b
u
r
i
e
d
di
rect
’,
C
c
= 0.
9.
Fo
r c
a
bl
es i
n
st
al
l
e
d
abo
v
e
g
r
ou
nd
C
c
= 1.
C
a
= A
m
bient te
m
p
erature, C
s
= So
il resistiv
ity, C
d
=d
ep
t o
f
b
u
rial, Ci= Th
erm
a
l
In
su
lation
,
I
b
=
th
e d
e
sign
o
f
cu
rren
t of circuit, I
t
= the value of curre
n
t for ingle circu
it at a
m
bient te
mperat
ure. For c
a
bles
in
stalled
abov
e gr
oun
d C
s
and C
d
=1.
For gr
oup
[
5
]
For ca
bles ha
ving cross secti
onal area
16mm
2
or l
e
ss, t
h
e
desi
g
n
val
u
e of m
V
/
A
/m
i
s
obt
ai
ne
d
by
m
u
l
tip
lyin
g
th
e tab
u
l
ated
v
a
lue b
y
facto
r
C
t
g
i
ven by
:
[
6
]
For AC
three phase
s
y
stem
[
7
]
Whe
r
e V
3ø
is
th
e three
ph
ase vo
ltag
e
drop (V), I is
t
h
e
nom
inal full l
o
ad
or
starting curre
nt as
applicable (A),
R
c
is the ac resistance of the
cable (
Ω
/k
m
)
, X
c
is the ac rea
c
tance of the c
a
ble (
Ω
/k
m
)
cos ø
is
the loa
d
powe
r factor
(pu) L i
s
th
e len
g
t
h
o
f
th
e cab
le (m
) [7
].
Evaluation Warning : The document was created with Spire.PDF for Python.
I
S
SN
:
2
088
-87
08
I
JECE Vo
l. 6
,
N
o
. 1
,
Febru
a
ry
2
016
: 3
4
–
39
37
For
AC single phase s
y
s
t
em
[
8
]
It
i
s
st
an
dar
d
s
t
o
i
n
di
cat
e m
a
xi
m
u
m
perm
i
s
si
bl
e v
o
l
t
a
ge
d
r
o
p
s,
w
h
i
c
h i
s
t
h
e m
a
xim
u
m
vol
t
a
ge
d
r
op
that is pe
rm
iss
i
ble across a
c
a
ble.
If t
h
e ca
ble exce
eds
th
i
s
vo
ltag
e
d
r
op
, th
en a
b
i
gger
cable size s
h
ould
be
pre
f
er
red
.
Greatest
v
o
ltag
e
d
r
op
s across a cab
l
e are sp
ecified
b
e
cau
s
e l
o
ad consu
m
ers will hav
e
an
i
n
pu
t
voltage
tolera
nce range.
If t
h
e volta
ge at the electrical
d
e
v
i
ce is lo
wer t
h
an
its
rated
min
i
m
u
m
v
o
ltage, th
en
t
h
e ap
pl
i
a
nce
m
a
y
not
w
o
rk appropriately
[8].
It
m
a
y
be m
o
re preci
se
t
o
ca
l
c
ul
at
e t
h
e m
a
xi
m
u
m
l
e
ngt
h
of a
cabl
e
fo
r
a part
i
c
ul
ar c
o
nd
uct
o
r si
ze
gi
ve
n a
m
a
xim
u
m
perm
i
ssi
ble v
o
l
t
a
ge
d
r
o
p
5%
o
f
n
o
m
i
n
a
l vo
ltag
e
at
fu
ll lo
ad
rath
er
th
an th
e
vo
ltage drop
i
t
s
el
f. To
co
ns
t
r
uct
t
a
bl
es
sh
owi
n
g
t
h
e m
a
xi
m
u
m
l
e
ngt
hs
co
rres
p
on
di
n
g
t
o
di
ffe
re
nt
c
a
bl
e si
zes i
n
o
r
de
r t
o
spee
d
up
t
h
e se
l
ect
i
on o
f
si
m
i
lar t
y
pe ca
bl
es.
For a three phase
s
y
s
t
em
[
9
]
For
a sin
g
le p
h
ase
sys
t
em
Tab
l
e
3
.
Shows th
e
p
e
rcen
tage of low
vo
ltage in
stallatio
n
su
pp
lied
vo
ltage
Lighting
Other
Uses
Low voltage installation supplied
directly fro
m
a p
ublic low voltage
distr
i
bution sy
stem
3% 5%
Low voltage installation supplied
fr
o
m
pr
ivate LV s
upply
(
*
)
6% 8%
[
1
0
]
A h
i
g
h
am
o
unt o
f
curren
t
will flo
w
th
rou
g
h
a cab
le for
a sh
ort ti
m
e
wh
en
th
ere is
sh
ort circu
it
h
a
pp
en
s i
n
th
e
circu
it. Th
is surg
e in
cu
rren
t fl
ow ca
uses
a te
m
p
erature rise
within t
h
e ca
bl
e.
High tem
p
eratures
can trigger unnecessa
ry reactions
in the ca
ble ins
u
l
a
tion,
sheat
h
materials and
ot
he
r com
pon
ent
s
, w
h
i
c
h ca
n de
gra
d
e t
h
e
con
d
i
t
i
on
of
the cable. Bigger ca
ble cr
os
s-sectional are
a
can
di
ssi
pat
e
hi
g
h
e
r
fa
ul
t
cu
rre
nt
s.
The
r
ef
ore
,
ca
b
l
es sh
oul
d
be si
zed t
o
wi
t
h
st
an
d t
h
e
l
a
r
g
est
s
h
ort
ci
rc
ui
t
.
The m
i
nim
u
m
cable size due
to short
circu
it
te
m
p
eratu
r
e
rise is typ
i
cally c
a
lcu
l
ated
with
an
eq
u
a
tion
of
the
fo
rm
:
[
1
1
]
The tem
p
erature rise
constant
is calculated
based
on
th
e m
a
terial p
r
o
p
e
rties of th
e cond
u
c
to
r and
the
in
itial an
d
fin
a
l
con
d
u
c
tor temp
erat
u
r
es as
p
e
r eq
u
a
tion
12
.
[
1
2
]
Evaluation Warning : The document was created with Spire.PDF for Python.
I
J
ECE
I
S
SN
:
208
8-8
7
0
8
An Effective Cable
Sizing
P
r
oced
ure
Mo
del
f
o
r
In
d
u
st
ri
es
an
d C
o
m
m
eri
a
l
Bui
l
d
i
n
gs
(Dr. K. Nith
iyana
nth
a
n
)
38
Fi
gu
re 2 s
h
o
w
s rat
i
ng fact
ors
t
o
be i
n
cl
ude
d
for m
o
re t
h
an
one ci
rc
ui
t
and cabl
e
s b
u
ri
e
d
di
rect
l
y
i
n
the ground
with ca
ble-
t
o
ca
ble clearance
(
α
).
Fig
u
re
2
.
Reductio
n
factors for m
o
re th
an
o
n
e circu
it,
si
ng
le-core
o
r
m
u
lti-
co
re cab
les lai
d
d
i
rectly in
the
g
r
ou
nd
.
4.
RESULTS
Tabl
e 4. V
o
l
t
a
ge dr
o
p
f
o
r di
ff
erent
El
ect
ri
cal
C
o
m
pone
nt
s
Nu
m
b
e
r
of
circuits
Cable to cable cle
a
r
ance (
a
)
a
Nil (cables
touching)
One cable
dia
m
eter
0.
125 m
0.
25 m
0.
5 m
2 0.
75
0.
80
0.
85
0.
90
0.
90
3 0.
65
0.
70
0.
75
0.
80
0.
85
4 0.
60
0.
60
0.
70
0.
75
0.
80
5 0.
55
0.
55
0.
65
0.
70
0.
80
6 0.
50
0.
55
0.
60
0.
70
0.
80
Tabl
e 5. Sam
p
le
o
f
cal
cul
a
t
i
o
n of
v
o
l
t
a
ge dr
op
usi
n
g V=IR
NO
DESCRIP
T
ION
MAX DIS
T
POWER
LOAD
VOLT
CURRENT
CSA
mV
/
A
/
m
DROP
REMAIN
VOLT
FROM
TO
(m
)
(W
)
(W
)
(V)
(A)
(m
m
2
)
(%)
(v
)
1 DB
L
i
ght
10
42
84
240
0.
35
2.
5
18
0.
2
0.
38
239.
63
Tabl
e 5 e
x
pl
ai
ns t
h
e
v
o
l
t
a
ge
dr
o
p
bet
w
een t
h
e o
r
i
g
i
n
o
f
an
i
n
st
al
l
a
t
i
on an
d any
l
o
a
d
poi
nt
sh
o
u
l
d
be
greater t
h
an t
h
e values i
n
the table below
expresse
d
with resp
ect to
t
h
e v
a
lu
e
o
f
t
h
e
n
o
m
in
al v
o
ltag
e
of
i
n
st
al
l
a
t
i
on. Ta
bl
e 6
s
h
o
w
s a
s
a
m
p
l
e
of
cal
cu
l
a
t
i
on m
e
t
hod t
o
cal
cul
a
t
e
t
h
e
vol
t
a
ge
d
r
op
.
The voltage
drop
for a
n
y particular
cable run m
u
st be voltage drop doe
s
not e
x
ceed
2.5%
of t
h
e
nom
i
n
al
vol
t
a
g
e
. T
h
e
nom
i
n
al
v
o
l
t
a
ge
dr
o
p
s
h
o
u
l
d
be
n
o
t
m
o
re t
h
a
n
2.
5%
vol
t
a
ge
f
r
om
m
a
i
n
swi
t
c
h
b
o
ar
d t
o
an
y po
in
t
of installatio
n
.
5.
CO
NCL
USI
O
N
Selecting
power ca
ble a
n
d types
of ca
bles
with t
h
e sizing of
t
h
e co
ndu
cto
r
s
for s
p
ecific
applications
is a v
e
ry essen
tial p
a
rt o
f
the p
l
an
of an
y electrical syste
m
.
Th
is task
th
at is o
f
ten
p
e
rfo
r
m
e
d
with
a least
am
ount
of e
f
f
o
rt
an
d
wi
t
h
m
i
nim
u
m
reflect
i
on f
o
r al
l
of t
h
e a
p
pl
i
cabl
e
desi
g
n
i
s
s
u
es. T
h
e co
ns
eque
nt
i
a
l
catastro
p
h
e
is th
at in
app
r
op
ri
ate selectio
n
an
d
sizing
can
easily a
m
p
l
ify
th
e in
stalled
co
st o
f
a facility wh
ile
also
dropp
ing
th
e reliab
ility o
f
th
e co
m
p
lete syste
m
.Th
i
s p
a
p
e
r
h
i
gh
ligh
t
s o
n
so
m
e
o
f
th
e co
n
s
i
d
eration
s
th
at
shoul
d
be
prac
tice for cable s
e
lection
eac
h a
n
d
eve
r
y
t
i
m
e
. It
t
h
e
n
s
u
g
g
es
t
s
t
h
e ri
ght
des
i
gn t
ool
t
o
cal
c
u
l
a
t
e
an
d facilitate th
e selection
p
r
o
cess
w
itho
u
t
reso
rting
t
o
simp
lificatio
n
s
.
Evaluation Warning : The document was created with Spire.PDF for Python.
I
S
SN
:
2
088
-87
08
I
J
ECE Vo
l. 6
,
N
o
. 1
,
Febru
a
ry
2
016
: 3
4
–
39
39
Nom
e
ncla
ture
Param
e
tes and
constraints
I
c
: In
stalled
curren
t
rating
(A)
I
b
: Base cu
rre
n
t
rating
(
A
)
K
d
: Prod
u
c
t
o
f
all th
e derating
facto
r
s
I
l
: Fu
ll lo
ad
curren
t
(A)
I
p
:
Pro
t
ectiv
e d
e
v
i
ce rating
(A)
C
c
: Circu
it bu
ried
in
t
h
e
g
r
oun
d
C
a
: Am
bient tem
p
erature
C
s
: So
il resistiv
ity
C
d
: D
e
p
t
h of
bu
r
i
al
C
i
: Th
erm
a
l Insu
latio
n
I
t
:
The
val
u
e
of
cu
rre
nt
f
o
r
i
n
g
l
e
circuit at ambient tem
p
erature
C
f
: Sem
i
-en
c
lo
sed
fu
se to
B
S
303
6
C
g
: Fo
r gr
oup
in
g
V
3ø
:
Th
ree
pha
se v
o
l
t
a
ge
dr
o
p
(V
)
I: cu
rre
nt (
A
)
R
c
: AC resista
n
ce
of the ca
bl
e (
Ω
/k
m
)
X
c
: AC
reactance of the
cable
(
Ω
/k
m
)
cos
ø: L
o
ad power factor
(pu)
L: Leng
th
of the cab
le
(m
)
A: Sh
ort circu
it te
m
p
eratu
r
e rise
k:
C
a
bl
e m
a
t
e
ri
al
pr
ope
rt
i
e
s
θ
f
: Fi
n
a
l co
nducto
r
tem
p
er
atu
r
e
θ
i
: In
itial con
d
u
c
tor tem
p
eratu
r
e
α
: cable- to ca
ble cleara
n
ce
REFERE
NC
ES
[1]
IEC 60364-5-52
, (2009)
, "Electrical installation
s
in build
ings
-
Part 5-52
: Selection and
er
ection of
electrical
equipment -
Wir
i
ng s
y
stems", is the
IEC
stand
a
rd governing cab
le sizing.
[2]
Nationa
l E
l
e
c
tri
c
it
y Cod
e
(NEC)
[3]
NFPA 70, (201
1), "Nation
a
l Electr
i
city
Code", is the
equivalent standard
for
IEC 60364 in
North America
and
includ
es a sectio
n cover
i
ng
cab
le sizing
in
Article 300.
[4]
BS 7671, (2008), "Requirements
for Electri
cal Ins
t
allations - IEE Wiring Regulations
", is the equivalen
t
standard f
o
r
IEC 60364
in
th
e United Kingdo
m.
[5]
Res
earch
pap
e
r
of As
s
e
s
s
m
ent of the
Qual
it
y of
Ca
bles produ
ced
in Nig
e
ria b
y
A
D
ETORO, K. A
D
EBAYO
[6]
Coker AJ,
Turner WO, Josephs ZT, (1991)
.
Elect
r
i
cal Wiring
. R
e
d
w
ood Press Limited, 12 –
28.
[7]
J
.
R J
a
ncaus
k
as
, “
C
able s
i
zing av
oid s
hortcut and
do it right”, IE
CEC 96 P
r
oceedings
of the 31
st
Iners
o
cie
t
y
Ene
r
g
y
Conversion Eng
i
neering
Confer
ence I
E
CEC-96
,
1996.
[8]
Nithiy
an
anthan
.K, Elav
enil V
,
(2011), ‘CYMGRD Based
Effective Earth
i
ng
Design Model for Substation
’
,
International Jou
r
nal for
Computer A
pplications in Engin
eering
S
c
ien
ces
Asia, Vo
l. I
,
No
3, pp. 34
1-346.
Evaluation Warning : The document was created with Spire.PDF for Python.