VCB

 
V.C.B PANEL

Safety Setting of VCB


1. Normal protection against overload:

I> 75% of In for 15 to 20 sec.(7 to 8 sec)

2. for short circuit current :

I>> 150% OF In for 8 to 10 sec.(2 to 4 sec)

3. Instantaneous Current:

I>>> 200% of In for 2 to 3 sec(.5 to 1 sec)

4. Ground Fault:

Io> : 150% of In for 3 to 6 sec.(1 to 1.5 sec)

5. Ground fault with phase :

Io>> 200% of In for 1 to 2 sec.(.5 to 1 sec)

V.C.B PANEL

Example: 


 Breaker 1000 amp(In):

1. 75% of In

1000*75/100 = 1000*.75 = 750 Amp.

2. 150% of In

1000*150/100 = 1000*1.5 = 1500 Amp.