Confused by Fuses

[Artemis]

In simple terms (if that is possible) what are the differences between Class L and Class RK fuses and what is the best application if used for service entrance?

 

[jim dungar]

In simple terms (if that is possible) what are the differences between Class L and Class RK fuses and what is the best application if used for service entrance?

Class L fuses are 601A and larger.
Class RK fuses are 600A and smaller.

Both are used for service entrances.

 

[MO_EE]

Jim is correct on the amp ranges, if the service is greater than 600A or could be expanded to that in the future then the Class L is the way to go. Otherwise it may be wise to choose the Class R fuse as there are more options for fuses which could be beneficial if a higher degree of current limitation is needed. The RK1 fuses provide more protection than the RK5 fuses do (in general.) Class J fuses may also be considered here if space is of concern.