How to calculate the current carrying capacity of
electrical cables
Answer Posted / abdul haseeb khattal
Well, First try to calculate the total load of the system.
For example total load is 1000KW. The current can be
calculated as P=1.732VICOS(PHI). Hence total current will
be 1732A by considering V=415volt, power factor=0.8.
Step2: To calculate the cable size
Vd = mV/L/A
where Vd= Allowable voltage drop which is normally 2.5
percentage to 4 percent.
L = Lenght of the cable from the source to feeder
A = Ampere rating
Let us consider L = 1000Meters
A = 1732A
Vd = 2.5 percentage of 415V as in U.A.E.
= 2.5*415/100 = 10.375
Use these value in the above formula
mV= Vd/L*A
= 10.375/1000*1732
= 0.005 volt
Refer to the cable catalogue in your region and find out
the current carrying capacity of the cable which will be
totally depend upon the atmospheric condition, in cold
place a smaller diameter of cable can carry larger current
and in hot areas the same size will carry lesser current.
In U.A.E. we are normally using 11x1c 630sqmm cable with
2500A incomer breaker. But cross check the voltage drop as
calculated above is within the limit of voltage drop of
these cables else you have to go to higher size of cable
untill the voltage drop met the design milli volt drop of
the cable.
| Is This Answer Correct ? | 16 Yes | 12 No |
Post New Answer View All Answers
how to find the resistance and gap volatage of the diode??
State thevenintheorem?
This is reqd for a 1MW Solar power plant..We have 2DC outputs from the solar panels Connected to 2INVERTOR panels.. Output from invertor is 3ph,280v,500kva,50hz.These are connected to individual ACB.This has to be stepped up to 11KV ,1250KVA SYSTEM.Now can I use (1) one more ACBTO GIVE A COMBINED OUTPUT OF 1000KVA,280V & STEP UP THE OUTPUT BY USING a single two winding 3 ph transformer 11kv/1250kva. or (2)use the two outputs and connect to one three winding transformer of above rating..Pls suggestwith details.
sir pls tell me . our ct specifications are 120/5 ,2 core , 0.2 and 5p10 class , 30va and 30va buden. insted of 30 va i want use 15 va. can i use?
in control panel, how can i measuring the distance between one bus bar to another bus bar. then now only for bus bar. in mpcb and contactor also. that means one mpcb to another mpcb how much distance? how can i calculate that.
I have a reading off 1.5ohms at my mem my main c/b is rated at 40/6 amps in a domestic house and i was told to change it to a b curve c/b is this ok
How can we calculate cable size in Low voltage & high voltage
1.what is difference between ATS & STS main use. 2.what is difference between ACB& VCB With symobles,and main partes, manimum range. 3.How many types of relays and main function.
The power factor of the fixed load is 0.8, now the p.f is varying from 0.8 to 0.5.
State kirchoff current law?
what is the difference b/w ground & virtual ground?
Why GRR starts from 60% of motor speed why not less than 60%?
What descriptive information does the NEC require to be marked on all conductors?
What is the diffrence (Technical & Construction ) between CBCT & Normal CT?
why the making current is more than then the breaking current and if its true then its about a controling circuit or breaker power contact points