ESTI-APPARATEBAU Ing. Sebastian Thielmann GmbH

Bundesallee 89 - 12161 Berlin / Germany - Tel +49-30-859 41 41 - Fax +49-30-859 41 70

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ESTI Excess Temperature Protector-Switch Ex 03

The Excess Temperature Protector-Switch Ex 03 comprises a flameproof contact element fitted into an Increased Safety enclosure. It is used to switch auxiliary, control and signal circuits in hazardous areas.

Working in hazardous areas, the safety of personnel and plant depends on complying with all relevant safety regulations.

Safety instructions:

Use the switch only for its intended purpose. No changes to the switch impairing its explosion protection are permitted.

Observe the following when setting up and operating the switch:

  • national safety regulations
  • national installation regulations (EN60079-14)
  • national accident prevention regulations
  • characteristic values and rated operating conditions on the rating and data plates.

The contact element must be replaced after each short-circuit in the switch main circuit. This is because the element is hermetically sealed and the state of the switching contacts cannot be checked.

The function of the ESTI-Protector-Switch:

The releasing element is the ESTI-Cartridge. Whenever the cartridge is heated the fluid contained in it expands. As soon as a predetermined critical temperature is reached the ESTI-Cartridge bursts. This bursting causes the release of electrical and mechanical impulses.

Confirmity to standards:

The Ex 03-Switch complies with the following standards and regulations:

Directive 94/9/EC: EN50014, 50018, 50019, 50041, 60647-5-1 und GS-ET15 (throughout Germany).

The type EX 03 is suitable for use in hazardous areas zones 1 ans 2.


Technical data:

Explosion protection: Ex II 2G (EEx ed IIC T6), Test certificate: PTB 01 ATEX 1053

Enclosure material: Polyamide, glass-fibre reinforced,

Ambient temperature range: -20 C+70 C

Degree of protection: Max. IP 65

Rated operating voltage: AC voltage for 1N/C+1N/O at same potential max. 500 V

AC voltage at differing potentials: Max.250 V

DC voltage : Max. 250 V

Rated operating current at temperature class T6:

With ambient temperature <=50 C: Max.10 A, with ambient temperature <=70 C: Max. 6 A

Rated impulse strength: 6 kV

Back-up fuse: 10 A

Connection cross-section of non-metallic sheathed cable (M 25 x 1,5): Max. 4 x 2,5 mm

Terminal cross-section (single-strand/multi-strand): Max.1 x 2,5 mm

Screw terminal tightening torque: Max. 0,4 Nm,

Contact opening distance: Min. 2 x 1,5 mm

Contact-material: Silver-nickel

Tightening torque for cover screws: Max. 0,7 Nm

Snap-action contact