Spring-Clamp Terminal
A spring-clamp terminal presses the conductor onto the contact bar with the constant force of a spring arm. Because that force depends on the spring's own characteristic rather than on the installer's torque, it resists loosening under vibration and thermal cycling better than the screw type.
In a screw terminal the contact pressure comes from the preload the screw creates; copper creeps over time, thermal cycling produces differential expansion and the preload drops. In a spring-clamp terminal the spring continuously compensates for that loss, applying a lasting force on the conductor.
- Assembly is repeatable: every end is pressed with the same force, so no installer-dependent variation appears.
- It is fast: on push-in types a ferruled end is simply pushed in, no tool required.
- End preparation is still mandatory: stranded conductor must be terminated with a ferrule, otherwise the strands spread out under the spring.
In vehicle, crane and construction-machine panels where vibration is constant, a spring-clamp terminal removes the need for retightening after installation. On high-current power connections, however, a bolted lug or power terminal is still preferred; spring types are used mostly on control- and signal-level cross sections.
The context in which this term is used: Installation, redundancy and field continuity