Strain relief on one or both sides?

Volker Beissel | 31. March 2020

It is known that strain relief can considerably increase the service life of cables and hoses in the energy chain. But an incorrect strain relief can also have the opposite effect. One point that comes up again and again is the question of whether strain relief should be mounted on one side or both sides? The answer is simple, it depends on the application! For most linear movements, you do everything right with strain relief on both sides. To be on the safe side, however, you must check whether the cables are moving relative to the e-chain. This is the case, for example, during a winding movement when the cables are not in the neutral phase. If this occurs, a strain relief must only be mounted on one side. Hoses make the whole thing more complicated even without relative movement, because they change their length by up to 5% under pressure. If the expected change of length in the chain is more than 2-3cm, strain relief should only be provided on one side. Otherwise the hose can destroy the energy supply system in the inner or outer radius or itself through abrasion.  

In summary, this means:

Strain relief on both sides: the cables do not move relative to the chain.

One-sided strain relief: the cables move relative to the chain.

Design tips for one-sided strain relief are available for the rotary energy supply systems: https://content.communication.igus.net/rotary-energy-supply-systems-design-tips

General information on strain relief is available here: https://www.igus.eu/info/energy-chains-filling-cables-and-hoses?L=en