CALCULATING MAXIMUM DEMANDDiversity factor for the four machines
in the Production area was assumed to be equal to 1and the
efficiency of the machines is 0.9.Three phase loads For Machine1
(MC1)I =P3V cos 0.95010334000.850.9I =94.34 A For Machine2 (MC2)I
=P3V cos 0.91510334000.850.9I =28.30 A For Machine3 (MC3)I =P3V
cos0.95.510334000.80.9I =11.02 A For he Air Condiioner (Assuming
the given power is the input power to the machineI =P3V cos
6510334000.85I =110.37 A For he p!"pI =101033V cos0.8I =21.27Total
current requirement for three phaseloads , By considering power
factor94.34 A+28.30 A+11.02+110.37+21.27265.3 A#in$le phase loads
For Machine% (MC%)I =PV cos 0.91.21032300.850.9I =6.82 A !y
considering the power factor" #otal current requirement for single
phase loads$ %.&'AAll #oc&e o!lesFor o''ice area1(A ring
type circuit with ) soc*ets ( +A ring type circuit with ) soc*ets (
For prod!cion area+A ring type circuit with ) soc*ets 'For o''ice
area,urrent requirement for1(A ring type circuit with ) soc*ets I
=131+130.753I2=42.25 A,urrent requirement for +A ring type circuit
with ) soc*ets I3=5+530.7516.25 A
For prod!cion area,urrent requirement for +A ring type circuit
with ) soc*ets I3=5+530.411 A (''ice Area Li$hin$-ffice area needs
two (1&' . fluorescent lamps.!allast consumption is assumed to
be 1.+.Power factor $ 0.9+I =PV cos (18+1.5)22300.95I =0.18 A#otal
current$ 1+ /0.1& $ '.0 ADiversity factor $ 0.9,urrent
requirement $ '.0 / 0.9 $ '.)( A!y considering power factor"
,urrent requirement $ '.)()rod!cion area li$hin$-ffice area needs
two (1&' . fluorescent lamps.!allast consumption is assumed to
be 1.+.Power factor $ 0.9+I =PV cos (18+1.5)22300.95I =0.18 A#otal
current$ '0 /0.1& $ (.% ADiversity factor $ 0.0+,urrent
requirement $ (.% / 0.0+$ '.0 A!y considering power factor" ,urrent
requirement $ '.0 A*ahroo" li$hin$( ,12 (11. bulbs are used for the
bathrooms.Power factor $ 0.9+I =PV cos 112300.95I =0.05 A#otal
current $ 0.0+/($0.1+ ADiversity factor $ 0.9,urrent requirement $
0.1+ 3 0.9 $ 0.1(+ A !y considering power factor" ,urrent
requirement $ 0.1(+A#in$le )hase Loads)hase +1or 4,)
5%.&'A2ighting (Production" bathroom and office 5%.)+A1(A ring
type circuit with ) soc*ets5 )'.'+A+A ring type circuit with )
soc*ets5 1%.'+A #otal current $01.00A )hase ,1(A ring type circuit
with ) soc*ets 5)'.'+A+A ring type circuit with ) soc*ets 51%.'+A+A
ring type circuit with ) soc*ets5 11A#otal current $%9.+A)hase *1(A
ring type circuit with ) soc*ets 5)'.'+A+A ring type circuit with )
soc*ets 5 1%.'+A+A ring type circuit with ) soc*ets 511A#otal
current $%9.+AToal E-!i.alen Line C!rrens)hase + #otal ,urrent $
01.00A6265.3 A $ ((0.00A)hase , #otal ,urrent $%9.+ 6265.3 A$
(().0&A)hase * #otal ,urrent $%9.+ 6265.3 A$
(().0&A7equired transformer power rating $ ( 3)00 3(().0& $
'((.+9*8A#eleced Trans'or"er +ain$ / 201&2A(''ice Area!athroom
lighting (,12Assume"Power factor to be 0.9+#he diversity factor to
be 1I =PV cos I =112300.95I =0.05 A( ,129s are used.4ethod :5
;nclosed in conduit on a wall ,< $ 1:5 Air conditioned
environment ,a $ 11luorescent lamps (set of two!y Assuming"Power
factor $ 0.9+!allast consumption to be 1.+.I =PV cos 1 I
=(18+1.5)22300.95I =0.18 A1+ 1luorescent lamps (set of two are
used.4ethod :5 ;nclosed in conduit on a wall ,< $ 1:5 Air
conditioned environment ,a $ 1,able 4ethod ' ,able diameter(mm'
,urrentcapacity (A8oltage drop(m8=A=m>narmored13'core
singlephase A, cable;nclosed inconduit on awall1 10 )%,able 4ethod
' ,ablediameter(mm'
,urrentcapacity (A8oltage drop(m8=A=m>namoured13'coresingle
phaseA, cable;nclosed inconduit on awall1 10 )%1or personal
computer Assume" #he efficiency of the machines to be 1#he
utili?ation factor to be 1#he power factor to be 1 #he diversity
factor to be 1I =30023011 1=1.30 A< @ 1(A" therefore 1(A square
pin soc*et outlets can be used. 1or photocopy machineAssume" #he
rated power is to be '000.#he efficiency of the machines to be 1#he
utili?ation factor to be 0.he power factor to be 1 I =200023011
0.8=6.96 A< @ 1(A" therefore 1(A square pin soc*et outlets can
be used. 1' soc*et outlets are used.' soc*et ring circuit of office
area< ( 13+1375 ) 0.6=13.65 A#herefore current flow through 1
conductor$13.652A$ %.&'+ A4ethod :5 ;nclosed in conduit on a
wall ,< $ 1:5 Air conditioned environment ,a $ 1:5 Ao. of
circuits is 1 ,g $ 1+ soc*et ring circuit of office area< (
13+134 75 ) 0.6=31.2 A#herefore current flow through 1
conductor$31.22A,able 4ethod ' ,ablediameter(mm'
,urrentcapacity (A8oltage drop(m8=A=m>namoured13'coresingle
phaseA, cable;nclosed inconduit on awall1 10 )%$ 1+.% A4ethod :5
;nclosed in conduit on a wall ,< $ 1:5 Air conditioned
environment ,a $ 1:5 Ao. of circuits is 1 ,g $ 1% soc*et ring
circuit of office area< ( 13+13575 ) 0.6=37.05 A#herefore
current flow through 1 conductor$37.052A$ 1&.+'+ A4ethod :5
;nclosed in conduit on a wall ,< $ 1:5 Air conditioned
environment ,a $ 1:5 Ao. of circuits is 1 ,g $ 1Three phase loads
(''ice Area1or the Air ,onditioner ,able 4ethod '
,ablediameter(mm'
,urrentcapacity (A8oltage drop(m8=A=m>namoured13'coresingle
phaseA, cable;nclosed inconduit on awall1 10 )%,able 4ethod ' ,able
diameter (mm'
,urrent capacity (A8oltage drop (m8=A=m>namoured 13'core
single phase A, cable;nclosed in conduit on a wall1.+ '' (1Assume"
#he efficiency of the A, to be 1I =P3V cos1I =6510334000.85I
=110.375 A4ethod :5 ;nclosed in conduit on a wall ,< $ 1:5 Air
conditioned environment ,a $ 1:5 Ao. of circuits is 1 ,g $ 1
)!"pAssume" #he efficiency of the pump to be 1I =P3V cos1I
=1010334000.85I =16.98 A8oltage drop due to 00m length 0.0(8 B
.here 8$)008 v=1000VI l,able 4ethod ' ,able diameter(mm'
,urrent capacity (A8oltage drop (m8=A=m>namoured 13)core
three phase A, cable;nclosed in conduit on a wall(+ 1'& 1.1+
v=10000.0340016.9870 v=10.0959mV / A/ m4ethod :5 narmored 1).1A
()5core4) 1mm'" 1(A" >narmored 1'.''A (' core8oltage drop at (0
11.0224.59525mV=6.776 8oltage drop as a percentage $ 6.776230
100=2.95As this is near to (F" if practically lengths get much
longer that might be an issue.#herefore"d(8($(0.0(G)00G10( =
(11.0'G').+9+$)).'0) m8=A=m,able area should be more than 1mm'!ut
according to the current carrying capacity cable area 1.+mm'#o
satisfy both conditions cable area should be 1.+mm'). 1or
4)PVinsulated" '5core cable" 1ph A,8oltage drop at (0 6.826.06944
mV=1.821 8oltage drop as a percentage $ 1.821230 100=0.791inal
cable selection for production area :Fi$!re 1MC* and Circ!i
3rea&er selecion1or soc*et outlets in the office and production
area7ating currents of various soc*et outlets1or office area1(A
soc*et ring type circuits $ )'.'+A+A soc*et ring type circuits $
1%.'+A1or production area +A soc*et ring type circuits $
11A,alculating short circuit currentsHere we calculate the short
circuit current of a soc*et outlet which is most far away from its
supplyterminal.Distance to the soc*et outlet (appro3imated $
)1mDiameter of the cable$ 1.+mm'7esistivity of cu $
1.%&/105&Im7esistance !lA $1.68108411.5106 $0.)+9'IEelected
,able 41 +0mm'" 11&A" >narmored4' %mm'" ()A" >narmored4(
1.+mm'" 1+A" >narmored4) 1mm'" 1(A" >narmoredEwitches 1mm'"
1(A" >narmoredEoc*ets 1mm'" 1(A" >narmoredEince this is a
ring circuit effective total $ 0.)+9'J' $ 0.''9%I 7esistance of the
live wire ,onsidering the neutral wire the total 7esistance of the
neutral wire is$ 0.''9%IHence total resistance under a short
,ircuit conditions $ 0.''9%/'$ 0.)+9'I#hen the total short circuit
current $2300.4592$ +00.&01A.e consider this soc*et and we can
assume that other soc*ets which are situated nearly to thesupply
end will undergo a higher short circuit current because of the
lesser impedance due to shorter length of the cable. #he other
cables which have a 1mm' cross section area will also have higher
currents due to less resistance caused by increased cross sectional
area.4agnitude of short circuit currents with respect to rated
current of the loads1or office area1(A soc*et ring type circuits $
11.&++A soc*et ring type circuits $ (0.&'1or production
area +A soc*et ring type circuits $ )+.+(1or these conditions we
can use type < mcb s for all ring circuits since they satisfy
the above conditions'.0
