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Anonymous Poster #1

How to Calculate Cable Size

04/20/2014 5:34 AM

How to calculate the cable size according with the load....
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Tornado
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#1

Re: how to calculate cable size

04/20/2014 7:52 AM

You don't; instead, you look it up in tables.

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lyn
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#2

Re: how to calculate cable size

04/20/2014 9:23 AM

This question gets asked, and answered EVERY DAY!!!!!!!!!!!!!!!!!!

Look on the web.

Do your own homework!
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redfred
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#3

Re: how to calculate cable size

04/20/2014 10:13 AM

You calculate the cable size by measuring the diameter (d) of the metal part of the round wire. You then use the standard formula for calculating the area of a circle. A close enough approximation is (11/14)*d*d≈ area. For square or rectangular wire the simple product of the two sides will also work but square wire is typically only used in tightly packed transformers and coils.

One does not calculate cable size based on just the load. The source voltage, acceptable voltage sag, cable path, insulation rating, circuit protection rating and most importantly if the maximum load the circuit will drive.

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Crabtree
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#4

Re: How to Calculate Cable Size

04/20/2014 12:28 PM

you don't. You get a qualified electrician to do the installation, and his warranty is his invoice, Mildred.

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navdeep_goyal
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#5

Re: How to Calculate Cable Size

04/20/2014 11:45 PM

Its very simple get manual from cable manufacturer
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Aghvel Niazi
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#6

Re: How to Calculate Cable Size

04/21/2014 3:50 AM

An outline how to calculate the Size of Power cables

1. Load Calculation/ Required Information:

Calculate the following:-

a.Total load,

b.Duty factor

c.Power factor and

d. Full load Amperes

also

e. Permissible voltage drop

f. Distance between source and load

g. Cable laying details

h. Soil details

i. Ground temperature

j. No of cables in trench

k. No of Run of cable

2. Total De rating Factor:

Following de-rating factors are to be determined depending upon the type of installation and site conditions:-

a.Temperature Correction factor in air

b.Ground Temprature Correction factor

c. Thermal Resistance correction factor for Soil

d. Soil Correction factor

e. Cable Depth correction factors

f. Cable distance correction factors

g. Cable grouping factor

Total De rating factor = a x b x c x d x e x f x g

(De rating factors can be obtained from cable manufacturers)

3. Power Cable selection:

Cable selected should satisfy the following conditions:-

a. Cable de rating amp should be higher than Full load current

b. Cable Voltage drop should be less than Defined Voltage drop

c. Cable Short Circuit capacity should be higher than System Short Circuit capacity

4. Provide required information and proceed further to sort out the solution
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Users who posted comments:

Aghvel Niazi (1); Crabtree (1); lyn (1); navdeep_goyal (1); redfred (1); Tornado (1)

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