• Standard rating available :
0 - 63 A → MCB
80 - 630 A → MCCB
800 and above → ACB
5 A
10 A
16 A
20 A
25 A
32 A
40 A
50 A
63 A
80 A
100 A
125 A
160 A
200 A
250 A
320 A
430 A
500 A
630 A
800 A
1000 A
1250 A
1600 A
2000 A
2500 A
3200 A
4000 A
5000 A
6300 A
For 3 - Ø
- If the rating in KW multiply with 1.9
KW × 1.9 = A
- If the rating in KVA multiply with 1.4
KVA × 1.4 = A
- If the rating in HP multiply with 1.5
HP × 1.5 = A
- If the rating in KVAR multiply with 2
KVAR × 2 = A
For 1 - Ø
- If the rating in KW multiply by 6 @ P.F. 0.8
= KW × 6 = A
- If the rating in KW multiply by 8 @ P.F. 0.6
= KW × 8 = A
Example :
If we selected a 160 kVA transformer
For 160 kVA ,
kVA × 1.4
160 × 1.4 = 224 A
For C.B again we will multiply by 1.25 safety factor.
224 × 1.25 = 280 A
Therefore, 280 A for 320 A MCCB recommend
Example 2 :
For 500 kVA transformer,
kVA × 1.4
500 × 1.4 = 700 A
Safety factor is 1.25
700 × 1.25 = 875A
Therefore,
For 875 A we selected 1000 A ACB is recommended.
• wire / cables with amper rating :
1.5 sq.mm -- 5 A MCB
2.5 sq.mm -- 10 A MCB
4 sq.mm --- 25 A MCB
6 sq.mm --- 32 A MCB
10 sq.mm --- 40 A MCB
16 sq.mm ---- 63 A MCB
Therefore, this are MCB rating and wire size for power and light system.
0 Comments