Connectwell din rail spring clamp 4mm terminal 1 in 1 out connectwell tteccsc4t in certain applications for smaller cross section range of wires screwless spring terminal blocks are available in spring clamp terminals the wire is held against the current bar directly by a pre stressed spring clamp the spring clamp is operated by using a screw driver to provide an access to wire through the opening in the spring clamp the wire end gets clamped on to the current bar on removal of the scr