Spring-Loaded Connection - Siemens 3UG4 User Manual

3.3.2

Spring-loaded connection

Spring-loaded connection
All SIRIUS monitoring relays have spring-loaded connections. They make wiring quick and
maintenance-free, while also meeting high demands in terms of vibration and shock
resistance. If the cross-section of a connectable wire is greater than 6 mm², the forces
required for operation of the tension spring are so high that the spring-loaded connection can
no longer be used in a problem-free manner. For this reason, size S2 current monitoring
relays are only offered with screw-type or spring-loaded terminals in the control circuit. The
terminals of the main current paths are always screw-type terminals.
①
②
③
④
a
b
Image 3-1
The conductors can be clamped directly or you can pre-treat them to add a form of splice
protection. This could involve attaching end sleeves or pin cable lugs to the ends of the
conductors; the tidiest solution is to use conductors whose ends have been sealed by means
of ultrasound.
3UG4 / 3RR2 monitoring relays
Manual, 05/2016, NEB927043002000/RS-AC/004
Solid
Finely stranded
Stranded
Finely stranded with end sleeve
Spring-loaded terminal
Busbar
Spring-loaded terminal
System overview
3.3 Connection methods
23