iNAL iNALF switch disconnectors

Air insulated Switch Disconnectors

Air insulated Switch Disconnectors

Model Number:UN-SD

Product Description

Air insulated Switch Disconnectors

switch disconnectors are based on a modular principle, which gives it a wide range of functioUN-SD. With a unique design that extinguishes electric arcs and enables high switching capacity, they represent an attractive solution as a key breaking element for applications in enclosed switchgear and transformer compact substations. In combination with type XRNT current limiting fuses, fuse switch disconnectors ensure control over the full range of overload and short-circuit currents.

The switch disconnector system  are consists of a frame with insulators and current carrying parts. Two different types of operating mechanisms, snap action mechanism type K or stored spring energy mechanism type A, can be mounted on the frame. Fuse bases type F, with or without fuse tripping mechanism, and an earthing switch type E/EB, suitable for both wall mounting and switchgear mounting.

Customer also can order shunt trip, under voltage release, auxiliary switches, motor operation.

The main areas of application of switch disconnectors are as:

  • Line switch disconnectors in medium-voltage networks
  • Switch disconnectors with fuses for the switching and protection of Distribution transformers &Motors


IEC60129, IEC60265, IEC60694, CSA C22.2, No. 193, and IEC 62271‑105,ANSI No. C37.20.4

Main product features

disconnector (which interrupts load currents up to 1,250 A) and a small fault-current circuit combined with a fuse base (F) and current limiting fuses (which break large short-circuit currents) create a iUN-SD-type disconnector that provides protection against a major fault types in a modern electric network.

    • Switchgear equipped with UN-SD switch disconnector
    • Switchgear equipped with switch disconnector
    • Structure of panel with UN-SD switch disconnector
    • Structure of panel with switch disconnector
    • UN-SD 36 KV fuse switch disconnector
    • 36 KV fuse switch disconnector

Basic designs

The standard feature consists of chassis, insulators and current carrying parts with the following pole distance:

  • 12 kV – pole distance 150 mm, 170 mm and 210 mm
  • 17.5 kV – pole distance 170 mm and 210 mm
  • 24 kV – pole distance 170 mm*, 235 mm and 275 mm
  • 36 kV – pole distance 360 mm

* with insulating barriers

Rated currents are:

  • 400, 630 and 1250 A up to 24 kV
  • 630/800/1000 A for 36 kV

Is delivered with the same pole distances as the standard feature. Fuse base type F is delivered for installation on both the opening

and pivot sides, with or without automatic tripping. A fuse base with six insulators can also be delivered separately with some form of sigUN-SD indication when a fuse blows or for installation on the pivot side of the switch.

Technical specification

Switch disconnector type

The switch disconnector complies with IEC standards 60129, 60254 and 60694 concerning general purpose switches and IEC Standards 420 and 62271-105 regarding correct co-operation between switch disconnector and fuse.

Switch disconnector type UN-SD