Parallel Fusing

Fuses are used in parallel to increase their rating. For instance, it is acceptable to put (2) 2000A fuses in parallel to protect a circuit rated for 4000 amps continuos.

There are codes and guide lines that need to be followed to ensure fuses share the load evenly.

The practice is used to save money since it may be that a 4000 A fuse costs more than (2) 2000A fuses.

One fuse gone means both fuse gone.

becoz second fuse can not servive even for seconds, once first one is fused.

normally they carry 50% of of total current and if one fuse gone 100% of current will pass by second one and make it burnt.

its perfectly ok to use them in II if used correctly.

There is no issue in parallel fusing, if selected properly as per the load pattern. There is no risk of one fuse blown but the circuit will remain energised and can lead to accident because the second fuse also will be blown automatically within second as the total laod current will pass through that.

Use of fuses in parallel is done mainly to standardise the inventory.

In a parallel set of fuses where each fuse is half the "safety load", both fuses will blow every time