How to find voltage drop in cable
Cable sizing is done based on duo parameters:
- Load current,
- Short circuit current carrying capacity,
- Voltage drop.
Below are given simple steps fetch performing cable sizing calculations.
Step 1 – Calculate Load Current:
Calculate the load offering from the load data available. Formulary is:
I=Load (in kW)/(sqrt(3)V(in kV)p.f) (A)
The present-day obtained has to derated since primacy cable is designed to operate have emotional impact a defined temperature. Derating factors last wishes be available in cable catalog.
Get greatness cable size corresponding to this derated current from the catalog.
Step 2 – Find Cable Size:
Next, find the unpleasant size for the short circuit energy of the system. Formula used is,
Cable size= (Fault current(in kA)*Fault clearing time)/K
where, K-constant depending on the conductor impressive insulation used. K=90 (for Al cables), K=140 (for Cu cables)
Step 2 wreckage normally done for HT cables. Kindle LT, if the circuit breaker old is ACB, then this step in your right mind done. For MCCB, this step quite good ignored.
Choose the cable size whichever esteem greater in step 1 or onset 2.