The compulsory SANS 1213:2018 standard for industrial cable glands defines cable glands as devices designed to permit the entry of armoured or flexible cable or insulated conductors into an enclosure while providing sealing and retention.
They also offer other important functions such as earthing, bonding, insulation, cable guarding, strain relief, or combinations of these. CCG explores this topic in more detail.
The main functions of cable glands are therefore summarised as follows:
- To terminate, hold, and retain the cable entering into an electrical enclosure or apparatus.
- To maintain the IP rating of an enclosure that seals off the cable entry against moisture, gases, and solids.
- To provide earth continuity for armoured cables.
For industrial electrical installations, the need for legal compliance with the installation standard
SANS 10142 is vital to ensure Occupational Health & Safety (OH&S) in the workplace, the security and safety of earthing systems, functional safety, the longevity of performance, and the continuity of electrical supply for critical plant and equipment.
With this in mind, it is a legal requirement that installers and specifiers select cable glands that can demonstrate independent testing and certification to the latest SANS 1213 Edition 3 standard.
This standard was recently updated and includes additional design aspects which cover the following critically important safety functions:
Material quality
Strict compliance with brass material grade CuZn39Pb3 to BS EN 12164 ensures the mechanical and electrical performance of cable glands.
Environmental influences
To demonstrate longevity in performance, glands must undergo salt-spray and sulphur dioxide tests for corrosion resistance, as well as weathering tests at extreme high and low temperatures.
Mechanical properties
- Tests for impact strength and resistance are conducted to demonstrate whether a gland is robust enough to withstand the rigours of installation and to endure heavy-duty service throughout the life of the electrical installation. Industrial glands typically require an impact strength of 20 joules.
- Cable retention/ cable clamping test: Cable glands are used to attach cables to equipment, and the cores of those cables are connected to terminals within the equipment. A cable gland’s function is to hold the cable securely in place and prevent any strain or twisting forces on the cable from being transmitted to the conductors.
- Torque test: This ensures that the cable gland can be installed and function correctly with sufficient clamping on the cable armour or compression of the seal(s). It also checks the strength of the entry threads against overtightening, as that is usually the weakest part of the cable gland.
Ingress protection
Cable glands should have an IP rating equal to or higher than that of the enclosure. Glands are therefore tested to SANS 60529 and are typically required to have IP ratings of IP66 and IP68.
Electrical properties
Tests to determine the suitability of cable glands and any associated earth tags under short-circuit fault conditions satisfy the following criteria:
- Equipotential bonding to electrical equipment.
- Equipotential bonding to metallic layer(s) of cable.
- Protective connection to earth.
- Electrical current test of up to 43 kA rms.
In addition to the test criteria in SANS 1213 Edition 3, other design properties, such as EMC and Low Smoke Zero Halogen (LSOH), are increasingly relevant for modern electrical systems.
Electromagnetic Compatibility (EMC)
This is the ability of the equipment, cables, or electrical systems to function satisfactorily in their electromagnetic environment without introducing intolerable electromagnetic disturbances to any other equipment in that environment.
Because electromagnetic emissions can be affected by the quality of the connection through the gland to the cable armour or metallic sheath and to the equipment testing according to EN 55011 and EN 55022 EMC standards, Class B radiation emissions demonstrate EMC compatibility.
Low Smoke Zero Halogen (LSOH)
With an increase in the amount of cable installed in residential, commercial, industrial, public buildings, metro rail tunnels, and underground mining operations, the specification of LSOH cables and accessories is increasingly becoming mandatory. During a fire, LSOH cables will emit less optically dense smoke, which makes exiting a space easier for its occupants as well as increasing visibility during firefighting and rescue operations. With zero halogen cables, the chance of toxic gases accumulating, which are life-threatening to people and corrosive to electrical and instrumentation equipment, is significantly reduced. To match the LSOH characteristics of the cable, it is necessary for the seals, gaskets, and shrouds of cable glands to meet the same LSOH standards as the cables. Testing to EN 45545-2, IEC 61034-2, and IEC 60754-2 standards demonstrates LSOH compliance.
Conclusion
As modern electrical systems and designs are becoming ever more high-tech and sophisticated, equipment and cables used in such systems must comply with various improvements made in safety and performance standards. It is therefore imperative that cable glands that are used to terminate, seal, and maintain adequate earth continuity and IP ratings between the cables and equipment need to perform to similar high standards.
Only cable glands that can demonstrate independent testing and certification to these standards should be selected for use in modern electrical system installations. According to SANS 10142, it is now a legal requirement that only glands that are certified to the latest SANS 1213 Edition 3 standard may be installed.
