Safety contact strips 8.2 kΩ – closing edge protection

Assembly, mandatory for 230/400 V drives, risk assessment & standards – including suitable components from Tormeister24.

What is a safety contact strip (8.2 kΩ)?

A safety contact edge (SKL) is a touch-sensitive switch sensor located on the closing edge of gates and doors. Upon contact or a risk of crushing, the resistance (typically 8.2 kΩ ) changes, and the control system stops or reverses the movement. The SKL thus fulfills the protective goals of gate safety.

Mandatory for sliding gates where there is no adequate power cut-off integrated or the risks (e.g. crushing/shearing) cannot be controlled in any other way.

Required components (assembly of a contact strip)

To assemble a contact strip, the following components are required:

1 × connection cable / end cap with connection cable – electrical connection
1 × 8.2 kΩ resistor – resistance monitoring (included with matching end caps/bars)
1 × Aluminum Profile - Carrier/K-Rail
1 × rubber profile – actual contact strip (65 mm, clip feet)

Matching products at Tormeister24

Rubber profile / contact strip 8.2 kΩ (65 mm)

Sommer safety contact strip, 8.2 kΩ, 65 mm, clip feet

Basic sensor for the closing edge.

End cap with connecting cable

Summer end cap + connecting cable (38×67×20 mm)

For electrical connection of the SKL.

End cap 8.2 kΩ

Summer end cap for 8.2 kΩ SKL

Resistance monitoring 8.2 kΩ.

Aluminum K-rail (beam)

Sommer K-rail 1000 mm × 30 mm × 10 mm

Holder for the contact strip.

component	function	Note on selection
Rubber profile (8.2 kΩ)	Sensory strip on the closing edge	Select height/width to match the door geometry (here 65 mm, clip feet)
aluminum profile (K-rail)	Mechanical carrier	Support surface, stable fastening (e.g. 1000 mm pieces aligned flat)
End cap 8.2 kΩ	Defines the monitoring resistance	Compatible with SKL profile; 8.2 kΩ permanently integrated or via resistor
Connection cable	Electrical connection to the control	Length for cable routing; weatherproof outdoor design

Assembly & assembly – step by step

Determine the length: Measure the closing edge (including tolerances/end caps). Allow 10–20 mm for a reserve.
Cutting and deburring aluminum profiles: Clean edges and ensure the contact surface is free of grease.
Clip in the rubber profile: Starting from one side, pull it in without distortion and ensure it fits perfectly.
Install end cap(s):
- One side: end cap with connecting cable
- Opposite: End cap 8.2 kΩ (or integrate resistor into the end cap)
Electrical connection: Lay the cable neatly (protected against kinks) and connect it to the safety inputs of the gate control (e.g. 8.2 kΩ input).
Functional test: Close the door in inching mode and trigger the SKL at several points – the door must stop/reverse.
Documentation: photos, test report, entry in the risk assessment.

Important: Transitions, corners, and joints must be free of dead zones. Install the strip flush, without waves; ensure the cable entry is water-resistant.

Mandatory for 230 / 400 V drives & safe design

Mandatory for 230/400 V drives: If the drive does not provide an integrated, standard-compliant power cut-off , a closing edge safety device using a safety contact strip is mandatory . The design must comply with the relevant standards (see below).

Fail-safe design: 8.2 kΩ monitoring → wire break/defect are detected.
Signal processing: Use the safety input of the control system; if necessary, provide an evaluation device/interface.
Environment: Observe IP protection classes, protect cable routes against moisture/UV.

Risk assessment & edges to be secured

A risk assessment must be prepared and documented before commissioning. It must include at least:

Closing edge analysis: main closing edge (travel path) and secondary closing edges (e.g. post areas, openings, crush/shear points).
Crushing/Shearing: Assessment of all points where people/objects may be at risk.
Environment & use: traffic frequency, visibility, children's areas, public vs. private.
Protective measures: SKL on main and relevant secondary closing edges, additional light barriers , warning lights, information signs.
Testing & Maintenance: Recurring functional testing, visual inspection, documentation.

In practice: Sliding gates often require protection of the main closing edge (direction of travel) and the post side (secondary closing edge). Additionally, light barriers should be installed for perimeter protection.

Relevant standards

EN 12453 – Power-operated doors and gates: Safety in use (protection objectives & strategies, including closing edge safety devices).
EN 12445 (Test methods; partly superseded by later documents) – Methodology for force/function testing.
EN 12978 – Safety devices for the protection of persons: Requirements for safety edges/sensors .
EN ISO 13849-1 – Safety of machinery: Performance level of safety functions (design, diagnostics, MTTFd).
EN 60335-2-103 – Safety of electric drives for gates, barriers and doors.

Note: State legal requirements (e.g. BetrSichV/workplaces) and manufacturer's specifications for the door system must also be observed.

FAQ

How do I check the contact strip?

With the door closing, gently press the SKL at several points. The drive should stop/reverse. Record the result.

Where is the 8.2 kΩ resistor located?

Depending on the system, it can be installed in the end cap or as a separate component. Correct connection to the monitored safety input is important.