1, What is NH fuse?

NH fuses (We call it NH Knife Blade Fuses or DIN NH Blade Fuses) were defined in the German DIN standard 43620 ... NH fuses are one-time fuses, meaning once they were blown, they must be replaced with a new fuse with the same characteristics.

NH fuse class gG which means general purpose fuse, also called  fuse class gL. gG class fuse element will melt within 2–5 seconds at 5 times of the rated current, and within 0.1–0.2 seconds at 10 times of the rated current.

Comparing with the semiconductor fuse,  NH fuse is time delay fuse. Which blow slower than high speed fuse, a very fast acting fuse might open in 0.1 second.

2, Where are NH fuses used?

It's used in motor protection(500VAC), semiconductor protection( 690VAC and 1000VAC), Solar PV protection( 1000VDC, 1500VDC), Battery protection(500VDC, 800VDC).

3, What's NH fuse sizing?

NH fuse with size 000, 00, 0, 1, 2, 3, 4;

NH fuse size 000 with current ratings during 2~100AMP;Fuse part #'s for example: 35NHG000B, 100NHG000B;

NH fuse size 00 with current ratings of 50~160AMP, Fuse part #'s are like: 50NHG00B, 160NHG00B;

NH Fuse size 0 with fuse current of 6~160AMP, Such as: 50NHG0B,  125NHG0B;

NH fuse size 1 with fuse curent of 6~355AMP, Such as fuse part #: 160NHG01B, 315NHG1B;

NH fuse size 2 with fuse curent of 35~500AMP, Fuse part #'s are like: 200NHG02B, 500NHG2B;

NH fuse size 3 with fuse curent of 250~800AMP, Fuse part #  for example: 315NHG3B, 630NHG3B;

NH fuse size 4 with fuse curent of 500~1250AMP, Fuse part #  such as: 800NHG4G, 1250NHG4G.

4, Fuse manufacturers cross reference 

Fuse size 000 Bussmann Cross reference

Bussmann Cross Reference of Fuse size 00    

Bussmann Cross Reference of Fuse size 0    

Fuse size 01  Bussmann Fuse Cross  

Fuse size 02  and 2 Bussmann Fuse Cross reference

Fuse size 03 and 3 Fuse Cross, Bussmann Cross Reference

Fuse size 4 Bussmann Cross Reference   

These are also more NH fuse on more manufacturers such as EFEN, Littelfuse etc. 

Believe that we can help you on any fuse questions.