Furutec busduct joint features a maintenance-free double-bolt joint design.

This double-bolt joint design system ensures a sufficient electrical contact area and good mechanical strength. Its high tensile clamping bolts in duct-duct jointing do not penetrate through the conductors. A spring steel material named as lead spring that is wider than the conductors, is used to ensure a sufficient pressure on conductor contact area. This clamped joint having benefitted from a decade-long Japanese Technology generates less heat at busduct joint as compare to bolted joint system, which necessitate the drilling or punching of holes through the conductors with the bolt holes causing distortion to the lines of current flow. This clamped joint with leaf springs also has a more even contact pressure than the one using bolt-through joint.

The technical difference between a clamped joint and a bolted joint (bolt thru design) can be referred from

http://www.copperinfo.co.uk/busbars/pub22-copper-for-busbars/sec7.htm

Clamped joints are easy to make with the full cross-section being unimpaired. The extra mass at the joint and hence cooling area helps to give a cooler running joint and with a well-designed clamp, gives a very even contact pressure. The further added advantage is that of easy erection during installation. A disadvantage is the much higher costs of the clamps and associated fixings.

Bolted joints are compact, reliable and versatile but have the disadvantage that they necessitate the drilling or punching of holes through the conductors with the bolt holes causing some distortion to the lines of current flow. This joint type also has a somewhat more uneven contact pressure than one using clamp plates.