DOCUMENT NO. E-CAL-001

TITLE CABLE SIZE CALCULATION

Your Project Number

REV Your Project

BY Your Client

CHKD Your Name here

APPRV'D

DATE 1 OF 1 A

Cable Number Load

Load Data

Motor Rating kW No. of Parallel Conductor

Rated voltage V No. of Adjacent Circuits

FL power factor (cosq) Full load current A

Power Frequency Current / Conductor (Io) A

Allowable Voltage Drop % Allowable Voltage Drop (Starting) %

Cable Data

Conductor size mm2 Copper Tmax operating (R) o

C

Number of Cores Ambient Air Temperature (A) oC

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

Conductor rating (IR1) A Grouping Factor (GF)

Operating Temperature:

Conductor derating = = A

Operating temperature = [Io/IR2]2 x [(RAA]

= deg Celcius

Voltage Drop (Normal Operating):Conductor resistance, 20

OC = Ohm/km = Ohm/m

Conductor resistance, 40OC = Ohm/km = Ohm/m

Conductor reactance = Ohm/km = Ohm/m

MCC busbar Voltage = V

Cable volt drop Vd3 = Io L [3 (RC cosq + XC sinq] = V %

Voltage at the load = - = V

Min. load volts = V @ Voltage Drop

Starting Current = X = A

Cable volt dip Vd3 = Io L [3 (RC cosq + XC sinq] = V %

Voltage at the load = - = V

Min. load volts = V @ Voltage Dip (Motor Starting)

Short Circuit Withstand (3 Fault):

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

t = s (Fault clearing time 5s)

K = (143 for Copper conductors PVC Insulated)

S = [(I"k x 1000)2t]/K = mm

2(Minimum cable size to withstand short circuit)

Notes:

The methods used in this calculation are based on the recommendations of IEC 60228, IEC 60364-5-54

Copyright 2008 - Ver Pangonilo - http://www.filipinoengineer.org - its free to use and modify but leave this copyright note.

Short Circuit Withstand OK

2

<5

143

0.5

18

394.2400

(IR2)

72.88

4

0.8

50

CABLE SIZE CALCULATION

COMPANY

LOGO

COMPANY NAME

50

50

0.000422(R40C) 0.4217

O)

400

667.6

166.9

90

40

15

Operating temperature is Acceptable!

(Vmin)

3

196

5.8

IR1 x DF x GF

(VL)

PROJECT No:

ENGINEERED BY:

CLIENT:

A

REVPAGE

PROJECT:

89.01

0.1040

392

370

(XC)

365.3

400

2%

1.445.778

Voltage Drop is Acceptable!

34.67 8.67

400

1.05

1

205.8

0.000391

0.0001

(R20C) 0.3910

340 15%

Voltage Dip is Acceptable!

(Vmin)

6 166.9 1,001.3

34.7

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

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

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 Conductors

50 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

IEC 60364-5-54

Table 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

Below this line are References Only

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

Final Temp

PVC 160

XLPE 250

EPR 250

Butyl Rubber 220

Below this line are References Only

Notes to Cable Calculations

1. 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 phase

4. 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.