Siemens 3TK28 Manual page 39

Connecting terminal blocks
Hazardous Voltage.
Can Cause Death, Serious Injury, or Property Damage.
Before starting work, therefore, disconnect the system and devices from the power supply.
Procedure for screw-type terminal blocks
Step Operating instruction
1 Insert the relevant cable into square on the screw-type terminal until it engages.
2 Hold the cable in the screw-type terminal.
3 Tighten the screw of the terminal in which the cable is inserted.
4 Pull on the cable to ensure it is screwed tight.
Procedure for spring-loaded terminal blocks
Step Operating instruction
1 To release the clamping springs, insert the flat-head
screwdriver as far as it will go into the square opening of
the spring-loaded terminal. Please observe a 10°
horizontal angular deviation of the screwdriver to the oval
opening.
2 Insert the cable into the oval opening as far as it will go.
3 Hold the cable in the spring-loaded terminal.
4 Remove the screwdriver.
5 Pull on the cable to ensure it is tight.
3TK28 safety relays
Manual, 07/2016, NEB926157502000/RS-AB/003
WARNING
Description of the individual safety relays
3.6 3TK28 safety relays with relay enabling circuits
Figure
39