• SITOR semiconductor fuses have a high varying load factor, which ensures a high level of operational safety and plant availability - even when subject to constant load change.
• The use of SITOR semiconductor fuses in LV HRC bases or Siemens switch disconnectors has been tested with regard to heat dissipation and maximum current loading. This makes planning and dimensioning easier and prevents consequential damage.
• Our high standard of quality ensures good compliance with the characteristic curve and accuracy. This ensures long-term protection of devices.

Operational classes

Fuses are categorized according to function and operational classes. SITOR semiconductor fuses, in LV HRC design, are available in the following operational classes:

• aR: for the short-circuit protection of power semiconductors
  (partial range protection)
• gR: for the protection of power semiconductors
  (full range protection)
• gS: The gS operational class combines cable and line protection with semiconductor protection
  (full range protection).

Parallel-connected fuses

Parallel-connected fuses offer maximum current and energy limiting that is clearly better than in the case of comparable single fuses. They also fulfill the special requirements for UL-certified fuses according to which fuses must be connected in parallel at the factory. Here is the original wording of the NEC document: "240.8 Fuses and circuit breakers shall be permitted to be connected in parallel where they are factory assembled in parallel and listed as a unit. Individual fuses, circuit breakers, or combinations thereof shall not otherwise be connected in parallel."