Electrical Cable Size Selection
Electrical Cable Size Selection: Puri Details Formula ke Saath
Bhai, cable chuna koi tukka marne ka kaam nahi hai. Galat cable se load nahi chalega aur cable garam hokar pighal jayegi. Aaj hum samjhenge ki ek Professional Electrical Engineer cable kaise chunta hai.
1. Current (Amps) Calculation: Pehla Kadam
Cable size load ke Amps par depend karta hai.
- Single Phase (230V): $I = \frac{P}{V \times PF}$
- Three Phase (415V): $I = \frac{P}{\sqrt{3} \times V \times PF}$
2. Copper vs Aluminum: Kaunsa Best Hai?
| Feature | Copper (Cu) | Aluminum (Al) |
|---|---|---|
| Conductivity | Bahut Achhi | Copper se 60% kam |
| Wazan (Weight) | Bhari | Halka |
| Cost | Mehanga | Sasta |
3. Voltage Drop ka Chakkar
Bhai, agar cable bahut lambi hai (50 meter se zyada), toh raste mein voltage drop ho jata hai. Industrial rule ke hisaab se voltage drop 3% se zyada nahi hona chahiye.
4. Temperature aur Derating Factor
Cable agar garam jagah par hai ya pipe ke andar bahut sari cables ek saath hain, toh cable ki current jhelne ki capacity kam ho jati hai.
5. Cable Size Chart (Standard)
- 1.5 sq.mm: Lighting load (upto 10A).
- 2.5 sq.mm: Power sockets/AC (upto 18A).
- 4.0 sq.mm: Heavy AC (upto 24A).
6. Interview Questions for Electricians
Q1: Armoured Cable kyun use karte hain?
Ans: Mechanical protection aur grounding ke liye.
Q2: XLPE aur PVC insulation mein kya fark hai?
Ans: XLPE 90°C jhel sakta hai, PVC sirf 70°C.
Safety Warning: Kabhi bhi Aluminum cable ko Copper ke lugs ke saath bina bimetallic paste ke na jodein!
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