New solutions cable entry systems reduce space and time

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Category: News
Published on Wednesday, 03 November 2021 11:00
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Designers of cabinets and panels used for power distribution, or for control of process, machinery, and robotics, must work under conflicting restraints and requirements: on one hand, more components, both active and passive, are installed inside the enclosure, as well as a number of human machine interface devices; on the other hand, space requirements impose limitations to the wiring of the increasing number of devices connected to the cabinet.

The traditional manner for entering cables into a panel or enclosure, and ensuring suitable protection of the equipment inside the enclosure against external agents (dust, liquids, unauthorized access) relies on cable glands: economical, safe devices providing sealing and strain relief wherever a wire or a cable must pass through the enclosure’s walls. A cable gland requires just a round cut [hole] in the wall, is easy to install, adjust and replace.

With the increasing complexity of such distribution and control panels, more problems arise when designing entry modes for wires and cables:

  • A large number of round cuts are required, which must be distanced enough to permit easy installation of the glands; this requires more assembly time, and possibly reducing the mechanical resistance of the panel wall
  • Rapid installation and commissioning of a complex system requires an increasing number of pre-terminated (terminated to a connector, cables and wires; such cables and wires cannot be passed through a standard cable gland

In recent years, a practical solution to these problems has been found with the introduction of multiple cable passing devices. A cable passing device consists of a square, rectangular, or round frame, which opens to house several separate ‘split inserts’. Cables, pre-terminated or not, are mounted into inserts, which are then assembled in the frame. This requires a single square, rectangular or round cut in the wall, which is also wide enough to allow passage of a connector: this can represent a significant reduction of time and labour costs. Variations of this design include – when only non-terminated cables are present – frames molded in a special elastomer, which can be punched to push the wire or cable through the punch. Other devices which take advantage of this design are ‘split cable glands’ which can be opened to allow mounting of a split insert; in this manner, one or more pre-terminated cables can be passed through a single round cut.

The solutions outlined above provide strain-relief and Ingress Protection (sealing) similar to that of a normal cable gland; to increase the strain-relief protection, small clamping devices can be added inside the enclosure; such clamping devices can also be used for grounding the cable shield, providing EMC protection.