Difficult environmental conditions such as dirt, lubricants, steel wool and temperatures between -22° and +122°F in particular make maximum demands on energy chains in the slip ring of this excavator. An igus® energy chain of the series E2/000 has been doing the job without any problems here for two years. The energy chain has a rearward bending radius, is 7.2 feet long and carries out a circular movement of 330°.