## Calculation of voltage drop and cable size

### Motor / Electrical load

- Calculate Voltage drop of Cable.
- Calculate Size of Cable.
- Calculate Current Capacity of Cable.

Software: | Cable designing program |

Version: | 22.8.2012 |

Developer: | Jignesh Parmar |

Size: | 99 Kb |

Price: | Free |

Download: | Right here | Get Download Updates | Get Technical articles |

michael eaton

Some people criticizing the calculations. There are many packages on the market that will calculate your cable size, volt drop etc. but at the end of the day you need to know what your doing. Even the best packages will throw up errors in calculations and if using these packages, you need to be knowledgeable to validate the output.

This is a good tool to get you to the result you need, but you need to know what your looking at, not blame someone else for producing a tool that dumbs down what you should be competent in knowing.

Ganesh

very useful spread sheets.thanks

hquocphu

SOMETHING WRONG IN DATASHEET:

PLPE resi

4cX4 5,53

4cX 6 3,7

4cX 10 2,29

4cX16 2,45

4cX 25 1,54

4cX35 1,11

4cX 50 0,082

4cX70 0,57

4cX 95 0,41

4cX 120 0,33

4cX 150 0,27

4cX 185 0,21

4cX 240 0,16

4cX 300 0,13

4cX 400 0,1

4cX 500 0,1

4cX 630 0,1

AND PVC

4cX4 8,89

4cX 6 5,53

4cX 10 3,7

4cX16 2,29

4cX 25 1,44

4cX35 1,04

4cX 50 0,77

4cX70 0,53

4cX 95 0,38

4cX 120 0,3

4cX 150 0,25

4cX 185 0,2

4cX 240 0,15

4cX 300 0,12

4cX 400 0,09

4cX 500 0,09

4cX 630 0,09

cahyo widodo

Please review bout voltage in your spreed sheet Mr. Jigness Parmar for the data in value cable if we implement type of cable Lt PVC arround of range cable size 4cX70 and 4cX95, the value of voltage drop so annoying me. The value of Voltage drop if we use 4cX95 should be smaller than we use 4cX70, but there is become bigger. i have put the value but i found the miss calculation i think, pardon me. Please review and give the your best development sir.

N M Venugopal

how do we size the cable when we have only load say 55 kW for a distribution board(3 pumps and lighting load) and at 415 v supply and a length of 400 m from source voltage to board.

M G Patel

Useful information

Parag Chamuah

Thanks for the work you have shared. I have few queries:

1.How do we know what is the phase value(φ)?

2.What is demand factor specifically?

bdthang

Very useful. It help me a lot!

kolumb

There is something wrong with the cable data – it’s impossible 3 different type cables with same Conductor Area, same matherial, to have 3 different Resistance (ohm/km).

Example – look first 3 cable types – PVC flexible, PVC insulated and XLPE insulated, for the same Conductor area (by example 1cX6), both Copper, resistance for the fist is 3.3ohm/km, for the second is 3,69ohm/km and the third is 1.53ohm/km.

May be the last one uses a super copper, twice better than first 2 :)

ENGR.MUHAMMAD YOUNAS KHAN

dear sir

I want to submit the formulas of cable sizing to those persons which are searching here and there.I appreciate of your current website which are publishing my cable sizing ideas.I am submiting another voltage drop and cable sizing formula.

1- Vd = 1.732 x I X L X PF/ (Area mm2 x conductivity of copper) ———-FORMULA 1

2- Area(mm2) = 1.732 x I X LX PF/(Vd x conductivity of copper) ———–FORMULA 2

WHERE:-

1.732 FOR THREE PHASE.

2 FOR SINGLE PHASE.

I = LOAD CURRENT.

L= LENGTH OF CABLE.

PF= POWER FACTOR.

Vd= VOLTAGE DROP.

CONDUCTIVITY OF COPPER AT 90 DEG.C = 41.66

CONDUCTIVITY OF ALUMINUM AT 90 DEG.C =25.64

DATA:-

1.732 FOR THREE PHASE.

I = 160 AMPS.

L= 200 METERS.

PF= 0.85

FIRSTLY WE CALCULATE THE VOLTAGE DROP.

Vd = 1.732 x 160 x 200 x 0.85/(70 mm2 x 41.66)

= 16.1547 volts —————(1) for copper conductor.

Area(mm2)b= 1.732 x 160 x 200 x 0.85/(16.1547 x 41.66)

= 70 mm2 ———-(2) for copper conductor.

if you want to use Aluminum conductor, apply conductivity of Akuminum which is above said.ABOVE CALCULATIONS ONLY FOR THREE PHASE.

FROM

ENGR.MUHAMMAD YOUNAS KHAN

M.SC.ENGG.MIEE(UK)

WAZIRABAD CITY, PUNJAB,PAKISTAN.

Ramkumar M

How you get Area size 70mm2 ?

jan

i dont have a voltage drop and sq.mm.i have only amps how did we calc the sqmm

Ch. Khalid Parvez Akhtar

Its a wonderful working.I must compliment you for this great work. Congratulations

Regards

Ch. Khalid Parvez Akhtar

Jalalpur Jattan

Gujrat

Pakistan

thiru

calc is wrong.Diff cable size should apear for Al & Cu.

m daley

can you give me the formula for calculating cable sizes please

osman

please send me

Kingsley

Very useful, Thanks.

thanasusankar.bec@gmail.com

Sir,

I have a query in cable designing excel spread sheet Ver.22.8.12, I would be much thankful If would get it clarified.

In sizing of cable for motor feeder, The “KW” entry is mentioned what? It is the mechanical output or electrical input. If it is the mechanical output, the actual electrical load consumed must be output/efficiency and the actual input current is

Full load ampere = Output power/(1.732*P.F*V*Eff)

If “KW” Entry is actual input power then Full load ampere = Input power/ (1.732*P.F*V), Efficiency is not required in this case.

But, in your case, the “KW” entry is multiplied with efficiency to obtain actual load consumed (May be the mechanical power output which is less than “KW” entry) and the motor amperage is calculated from the actual load consumed. In such a case loses may not be able to feed to obtain desired full load output.

As far as demand factor concerned it (Load factor) is okay.Please clarify.

T.Sankar

Accesstel

Hi guys please let me know if we can buy these tools if they are not downloadable. I have invested 4 hours now with no success.

Edvard

Go ahead and register here: http://electrical-engineering-portal.com/wp-login.php?action=register

If you have problems, contact me here: http://electrical-engineering-portal.com/contact

Rajesh SV

Hi EEP members…..Am not able to download any of the spreadsheets…Plz advice.

Edvard

Are you registered member? If you are a member and still not able to download spreadsheet, please refer to F.A.Q. – http://electrical-engineering-portal.com/frequently-asked-questions

Jonesy

cannot down load!

Arnon

Nice !!!!!!

Donie

Useful! :)

wnirut

thank you

engele

Hi there,

would appreciate it if you could send a copy of the excel file to emile.engel@petrosa.co.za thanks

gabrielovskys

Tried but still i am not able to download the spreadsheet after login. Please kindly send excel file to gabriel.garcia@iie.org.mx……. Thank you

celebrationcometh

Tried but still i am not able to download the spreadsheet after login. Please kindly send excel file to ooluwakueshe@yahoo.com. Thank you

celebrationcometh

Same here. not able to download the spreadsheet too after log in.

Please help out

gurunadh006007

hello

i want to know the logics so please provide me password for this cable designsheet

sam atlantis

The link is not working even after LOGIN. Pls update the link.

Edvard

Hi,

Make sure to enable cookies in your browser. If cookes aren’t enabled, browser doesn’t know when you’re logged in.

I just checked, this spreadsheet has been downloaded 4763 time so far ;)

Hope you will make it!

neeraj tiwari

i am unable to download excel sheet suggest me for same.

neeraj tiwari

i m not able to download excel sheet suggest me for same.

Edvard

Go ahead and register here:

http://electrical-engineering-portal.com/wp-login.php?action=register

After you login here:

http://electrical-engineering-portal.com/wp-login.php

all download links will be available.

BR,

Edvard

hadi218

i register in above link but still i m not able to download please if possible send excel file to hadi451@gmail.com.

thanks

GnMvP

No DC cables?

Hamada666666

very good program

Veeraraghavan VS

Dear Edvard,

I tried the cable selection excel sheet. It is very good. I am giving below my observations.

1. Why there are 2 PFs? C9 and C10 are OK. Why C15?

2. Once a 3 Ph motor is selected, all single core and 3.5core cables may disappear from the list for selection.

3. In the results, Starting voltage drop as % will be helpful to refer.

4. It may be better if the TDF (Total Derating Factor) considered in selection is displayed.

5. As a case study, i considered a 55KV, 433V, 3Ph motor. DOL Start, 0.85 Running PF, 0.3 Starting PF, 85% efficiency, 600m length, LT XLPE Al cable, 3 trays, 6 cable per tray, cables touching each other. According to my earlier calculation 3cx50 cable is not suitable – 10.23% Running voltage drop and 24.41% starting voltage drop. But this sheet is showing OK with 1.95% running voltage drop.

The TDF considered by me is 0.674. Of course, the resistance and reactance data are from Indian cable manufacturers.

Please let me know your opinion / observation. 3cx50 al cable for a 55KW motor in DOL starting for 600m distance – please check.

Pedro Abarca

My coment is that I need a electrical software

jm010809

I use manual calculations since not all form of installation is covered on this spread sheet….