CABLE SIZE CALCULATIONDOCUMENT NO. E-CAL-001

COMPANY NAME TITLE CABLE SIZE CALCULATION

PROJECT No: Your Project Number

REV A PROJECT: Your Project

BY CLIENT: Your Client

CHKD ENGINEERED BY: Your Name here

APPRV'D

DATE PAGE 1 OF 1 REV A

Cable Number Load

Load Data

Motor Rating 370 kW No. of Parallel Conductor 4

Rated voltage 400 V No. of Adjacent Circuits <5

FL power factor 0.8 Full load current 667.6 A

Power Frequency 50 Current / Conductor (Io) 166.9 A

Allowable Voltage Drop 2 % Allowable Voltage Drop (Starting) 15 %

Cable Data

Conductor size 50 Tmax operating 90

Number of Cores 3 Ambient Air Temperature 40

Total Cable length (L) 50 m Temp. Cable Derating (DF) 1.05

Conductor rating 196 A Grouping Factor (GF) 1

Operating Temperature:

Conductor derating = = 205.8 A

Operating temperature =

= 72.88 deg Celcius

Operating temperature is Acceptable!

Voltage Drop (Normal Operating):

= 0.3910 Ohm/km = 0.000391 Ohm/m

= 0.4217 Ohm/km = 0.000422 Ohm/m

Conductor reactance = 0.1040 Ohm/km = 0.0001 Ohm/m

MCC busbar Voltage = 400 V

Cable volt drop = = 5.778 V 1.44 %

Voltage at the load = 400 - 5.8 = 394.2 V

Min. load volts (Vmin) = 392 V @ 2% Voltage Drop

Voltage Drop is Acceptable!

Starting Current = 6 X 166.9 = 1,001.3 A

Cable volt dip = = 34.67 V 8.67 %

Voltage at the load = 400 - 34.7 = 365.3 V

Min. load volts (Vmin) = 340 V @ 15% Voltage Dip (Motor Starting)

Voltage Dip is Acceptable!

I"k = 18 kA (From Short Circuit Calculations result)

t = 0.5 s

K = 143 (143 for Copper conductors PVC Insulated)

S = = 89.01 (Minimum cable size to withstand short circuit)

Short Circuit Withstand OK

Notes:

The methods used in this calculation are based on the recommendations of IEC 60228, IEC 60364-5-54Copyright 2008 - Ver Pangonilo - http://www.filipinoengineer.org - its free to use and modify but leave this copyright note.

COMPANYLOGO

(cosq)

mm2 Copper (ÆR) oC

(ÆA) oC

(IR1)

(IR2) IR1 x DF x GF

(ÆO) [Io/IR2]2 x [(ÆR - ÆA)+ÆA]

Conductor resistance, 20OC (R20C)

Conductor resistance, 40OC (R40C)

(XC)

(VL)

Vd3Æ Io L [Ö3 (RC cosq + XC sinq)]

Vd3Æ Io L [Ö3 (RC cosq + XC sinq)]

Short Circuit Withstand (3Æ Fault):

(Fault clearing time £ 5s)

Ö[(I"k x 1000)2t]/K mm2

Note: These data are based on a cable manufacturer's datasheet. Refer to your cable manufacturer for more information.

Cable Data (PVC Insulated Cables Only)

Item

1 16 2.5 1.16 1.48 0.116 0.14 96 2240

2 25 4 0.734 0.936 0.11 0.132 127 3500

3 35 6 0.529 0.675 0.106 0.128 157 4900

4 50 6 0.391 0.499 0.104 0.125 196 7000

5 70 6 0.27 0.344 0.099 0.119 242 9800

6 95 10 0.195 0.249 0.097 0.116 293 13300

7 120 10 0.154 0.196 0.094 0.113 339 16800

8 150 10 0.126 0.161 0.092 0.111 389 21000

9 185 10 0.1 0.128 0.091 0.109 444 25900

10 240 16 0.0762 0.0972 0.089 0.107 522 33600

11 300 16 0.0607 0.0774 0.087 0.105 601 42000

Temperature Correction Factor Frequency Parallell Conductors50 1

Item Temp, Deg C Factor 60 2

1 35 1.1 3

2 40 1.05 4

3 45 1 5

4 50 0.94

5 55 0.88

6 60 0.82

7 65 0.74

8 70 0.67

9 75 0.58

10 80 0.47

Below this line are References OnlyIEC 60364-5-54Table 54B Values for K for insulated protective conductors not incorporated in cables

PVC XLPE EPR Butyl Rubber

Final Temperature, degC 160 250 250 220 1

1 Copper 143 176 176 166 2

2 Aluminium 95 116 116 110 3

3 Steel 52 64 64 60 4

Cross section core, mm²

Cross section

screen, mm²

Max. conductor

resistance at 20°C,

Ohm/km

Max. conductor

resistance at 90°C,

Ohm/km

Reactance at 50Hz, Ohm/km

Reactance at 60Hz, Ohm/km

Current rating IEC,

Ampere

Short circuit rating

1second, Ampere

Note: These data are based on a cable manufacturer's datasheet. Refer to your cable manufacturer for more information.

Below this line are References Only

Final Temp

PVC 160

XLPE 250

EPR 250

Butyl Rubber 220

Notes to Cable Calculations1. Cable data provided in here are based on a manufacturer's datasheet. Refer to your cable manufacturer for project specific values.2. Cable calculation is based on IEC standards.3. Load data is based on motor load and 3 phase4. This calculation is just a sample. It is always a good practice to verify the results.5. I"k should be based on the short circuit calculation result. It is not part of this worksheet.6. Please read the Disclaimer Statement before using this calculation worksheet.

1. Cable data provided in here are based on a manufacturer's datasheet. Refer to your cable manufacturer for project specific values.