Siemens SITOR: fast-acting protection for semiconductor devices


Fuses are electrical devices that protect equipment, installations or lines from short circuits, as well as from strong overloads. For example, they can quickly and safely disconnect lines.

Their main components are a fuse-link, which is connected to a protected line and an interrupter chamber, which extinguishes the electric arc, which results from the fuse blown out.

Siemens offers SITOR fuses, which are fast-acting NH fuse links. These devices are universal, used in residential buildings, industrial plants, small plants, power supply systems, etc. They provide protection against short circuits of power semiconductors, in particular, GTO, thyristors and diodes.

The Siemens fuses is particularly resistant to alternating loads due to its design. Account of constant time in closed loop circuits allows drawing conclusion that the SITOR fuses can also be used in DC circuits.

Types 3NE4 1, 3NE3 2, 3NE8 7, 3NE3 3 and 3NE 0 have a category of application aR, which means fast protection of semiconductors with breaking capacity only in part of the range. The exception is rated currents ≤ 63A (series 3NE8 7 ≤ 32A).


3NE 1-0.

A new series with rated currents from 16A to 630A in the category of using gR (has a semiconductor protection with breaking capacity over the entire range). The purpose of these fuse links is the protection of semiconductors and the protection of conductors against overloads and short circuits.

3NE3-2, 3NE3-3

Series 3NE3-2, 3NE3-3 comply with DIN 43 653, they are used in LV HRC fuse holders, in safety disconnectors. Have the size of the installation with bolted connection 110 mm.

3NE1-0, NE4 1, 3NE8 0

Series 3NE1 ...- 0, 3NE4 1 ... and 3NE8 0 ... are in accordance with DIN 43 620. They can be used in both LV HRC fuse holders and in safety disconnectors.

3NE8 7

The 3NE8 7 ... 1 series conforms to DIN 43 653, has a mounting size with a bolted connection of 80 mm, is used for screw connection in devices.


  • Application categories aR and gR (for semiconductor protection).
  • Dimensions comply with DIN 43 620 (DIN 43 653 for 3NE87). 
  • Standard DIN, VDE 0636 and IEC 60 269. 
  • Voltage: 690 V AC, 660 V AC, 1.000 V AC.

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We guarantee professional help in choosing the optimal model that meets specific tasks, as well as the high quality of each product.

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