How to determine the current setting of a relay fuse?
How to determine the current setting of a relay fuse? Discrimination is required between the relay and both the fuse and MCCB up to the 40kA fault rating of the board. To begin with, the time/current characteristics of both the 400A fuse and the MCCB are plotted in Figure 18.19. 2a. Determination of relay current setting Which is an example of an overcurrent relay? Grading of Fuses / MCCBs / Overcurrent Relays An example of an application involving a moulded case circuit breaker, fuse and a protection relay is shown in Figure 3. What are the characteristics of a 400A...