Snap-action switch S820 – Microswitch for increased current carrying capacity

Robust changeover contact with galvanic isolation and positive opening.

S820 b Snap-action switch S820 with pushbutton, screw connections and blow-out magnets
S820 a L Snap-action switch S820 with roller lever, screw connections and blow-out magnets

The S820 snap-action switch is a robust microswitch with positive opening. Its contact system and shifting gate are designed for the conducting and disconnecting of high currents. At 20 amps, the continuous thermal current is twice as high as in other snap-action switches of the ‘F’ design, and the switch power is also multitudes greater than other snap-action switches. Thanks to its strong springs, this microswitch holds its switch state even in the event of heavy shocks and vibrations. The S820 is used in particularly tough conditions. The two contact bridges of the changeover contact can connect two galvanically isolated electric circuits. The break contacts are protected by a mechanical positive opening. The S820 is therefore suitable as an end position switch or position switch in safety applications.


Changeover contact with two galvanically isolated contact bridges.

Microswitches with two galvanically isolated contact bridges which are both attached in the plunger and are guided by it. When the snap-action switch is actuated, the bottom bridge opens the bottom contact pair (connections 1 and 2) and the top bridge closes the top contact pair (connections 3 and 4).

Continuous thermal current up to 20 A; disconnecting high power ranges

A contact bridge spreads the breaking capacity over two contact points. The contact material is silver. For the switching of high direct currents, we recommend blow magnets for preventing electric arcs (optional).

Break contacts with positive opening

If the break contacts fuse in the event of a short circuit, the catch spring can no longer open. It is nevertheless opened reliably via the lever of the positive opening. This is a positive opening as outlined in DIN EN 60947-5-1, annex K.

Shock resistance 60 g, vibration resistance 50 g

The switch mechanism of this microswitch has been designed to be especially robust. Catch springs and return springs are designed so that the switching process works reliably even in the event of shocks and vibrations.

Dimensions 50 x 55 x 12 mm (L x H x W)

This is the maximum dimensions of the housing. The dimensions of the actuator and of the connections must be added. For all dimensions and drawings please refer to the following product catalogue:



Electrical Data
Contact configurationSPDT-DB (Form Za) snap-action switch with 4 terminals, positive opening operation, and 2 galvanically isolated contact bridges
Conv. thermal current Ith EN6094720 A at T = 85°C
Conv. thermal current Ith UL50810 A at T = 85°C
Rated insulation voltage Ui EN60947400 V
Rated insulation voltage Ui UL508300 V
Pollution degree IEC 60947PD 3
Pollution degree UL508PD 3
Rated impulse withstand voltage Uimp4 kV
Utilization category IEC 60947AC-15, 230 VAC/5.0 A / DC-13, 110 VDC/1.0 A
Utilization category UL508240 V AC/1.5 A / DC 120 VDC/1.0 A (General Purpose)
IP rating: contacts/terminalsIP40/IP00
Contact materialSilver
Short-circuit protection10 A gL
Actuators, operating positions
ActuatorPush button, roller lever
Free position9.00 ±0.15 (push button)
Operating position6.00 ±0.35 (push button)
Release position8.00 ±0.35 (push button)
Total positive opening travel5.20 (push button)
Total travel position5.00 min. (push button)
Movement differential (between operating and release position)2.00 (typical, push button)
Mechanical data
Front mountyes, front mounting by nut retainers M3
Ganging (side mount)yes, side mount
Vibration resistance50 g (10 … 500 Hz all directions, without aux. actuator at 0.1 ms max. opening time)
Shock resistance60 g, half sinus (without aux. actuator at 0.1 ms max. opening time)
Housing materialPC, beige transparent
Mechanical endurance1 million cycles min.
Temperature range-40 °C ... +85 °C
NoteData valid for new switches with silver contacts

Related Downloads

Catalogue D20 – Snap-action switches S800, S804, S814, S820
Changeover switches with double-break contacts and positive opening operation
Safety instructions snap-action switches
Snap-action switches S800 / S804 / S814 / S818 / S819 / S820 / S826 / S834 / S840 / S845 / S846 / S847 / S850 / S870 / S880 / S926 / S947 / S970
Safety instructions snap-action switches / Supplementary details
Snap-action switches S800 / S804 / S814 / S818 / S819 / S820 / S826 / S834 / S840 / S845 / S846 / S847 / S850 / S870 / S880 / S926 / S947 / S970
Manual SE-M
Snap-action switches S800 / S804 / S814 / S818 / S819 / S820 / S826 / S840 / S845 / S846 / S847 / S850 / S870 / S880 / S926 / S947 / S970 — Installation and Maintenance Instructions
/en/products/snap-action-switches/thank-you/Snap-action switch S820 Snap-action switches

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