NH Types fuses or Bussmann fuses; Most widely used fuse

NH Type (Bussmann) Fuses – Overview & Specifications

Introduction

NH-type fuses (commonly known as Bussmann fuses) are the most widely used fuse links in industrial electrical systems. They are available up to 1.25 kA rating and are specifically designed for the protection of conductors, cables, motors, and switchgear against overloads and short circuits.

---

Fuse Characteristics

1.      gL-gG Fuse Links

o    Application: General purpose protection of cables and installation lines.

o    Function: Protect against both overload and short-circuit conditions.

2.      aM Fuse Links

o    Application: Dedicated protection for motors and switchgear.

o    Function: Provide short-circuit protection only (overload protection must be provided by relays/other devices).

---

Applications

NH fuses are widely used in:

·         Electrical substations (distribution protection)

·         Electrical panels (control & distribution boards)

·         Main house supply (service protection in LV systems)

---

NH Fuse Sizes and Ratings

Size	Current Range (A)	Approx. Blade Length (mm)
00/000	6 – 160	78
0	6 – 160	125
1	80 – 250	135
2	125 – 400	150
3	315 – 630	150
4	500 – 1,000	200
4a	500 – 1,250	200

---

Key Advantages

·         High breaking capacity up to 120 kA (depending on design).

·         Fast operation under fault conditions, ensuring system safety.

·         Interchangeable sizes with standardized dimensions (DIN standard).

·         Clear visual indication of blown fuse (in most types).

---

⚡ Summary:
NH-type fuses are standardized, reliable, and widely adopted in industrial and residential applications. They ensure system protection through their gL-gG (general purpose) and aM (motor short-circuit protection) variants, with current ratings extending up to 1,250 A.

---