Why Mfg increase HRC fuse breaking capacity

[NM13]

Recently Siemens has increased the 415 V HRC fuse breaking capacity to 120 KA, Why it happens??

As a end user how we can choose right breaking capacity for 415 V system ?? particulraly for 415 V Motor Feeders.

 

[ScottyUK]

Breaking capacity of a fuse has to be higher than your prospective maximum fault current, not matched to it. I would wary at the prospect of using, say, a BS88 fuse with an 80kA breaking capacity on a circuit with an 80kA fault level. The chances are nothing bad would happen, I just avoid taking things right up to the limit wherever possible.

Siemens are likely adapting to market demand for higher breaking capacities as LV fault levels get higher, especially in Europe and in the European sphere of influence where LV fault levels have typically been lower than the equivalents in North America. IIRC, 200kA breaking capacity isn't unusual for North American fuses.


----------------------------------

If we learn from our mistakes I'm getting a great education!