During FAT, there will be a Mechanical Operation Check to be done to ensure the mechanical operation and interlocking for the followings are in order :
1. VCB
a. the breaker can be racked in and out smoothly
b. when in the Connected Position : earth switch cannot be closed, control plug cannot be removed, when VCB closed - breaker cannot rack out, when VCB opened - breaker can rack out, VCB door cannot be opened
c. when in Intermediate Position : VCB cannot be closed and control plug cannot be removed
d. when in Disconnected Position : VCB door can be opened, earth switch can be closed and control plug can be removed
Note :
VCB cannot be connected when the VCB is closed, there is no control plug inserted, earth switch is closed and the door is opened.
2. EARTH SWITCH
a. it can be opened and closed smoothly
b. minimal rebounce on the blade
c. the padlock facility is provided
d. there is mechanical / electrcal interlock
3. SAFETY SHUTTER
a. smoothly open and close
b. the padlock facility is provided
c. latching facility provided
d. self-cancellation for latching facility in working condition
4. PT SHUTTER
a. smooth opening and closing
b. padlock facility provided
5. KEY INTERLOCKS
a. the key is released when breaker in disconnected position
b. VCB cannot rack in unless key is inserted
~ the above notes have been taken during my FAT at one of the well-known manufacturer of VCB in Malaysia
