Bimed Products Earn UKCA Certification for Continued Service to the UK Market
2026-04-15
An explosion-protected cable gland is the critical interface between cable and equipment in a hazardous-area electrical installation. Correct selection affects the integrity of the type of protection and overall safety. This guide reviews seven key considerations.
An armoured cable has a metallic layer, such as steel tape or steel wire, around its insulation. Armour improves mechanical strength and resistance to tension, compression and impact. Such cables are used in demanding locations, including mines and industrial plants.
Armour termination: select a gland with a clamping arrangement that matches the armour construction. An armour cone, clamping ring or gripping jaws should retain the armour under pull and vibration.
Sealing: the insulated cores still need effective protection. Age-resistant, elastic materials such as nitrile rubber or silicone rubber can form one or more seals to keep dust, water and corrosive gases from passing between cable and gland into the equipment.
Mechanical strength: the gland body must withstand cable tension and external loading without deformation or damage. The article gives nickel-plated brass and 316L stainless steel as examples.
Unarmoured cables have no metallic armour. Their insulation and sheath protect the conductors, and their flexibility makes them suitable for locations with lower mechanical-damage risk, such as indoor distribution and control circuits.
Seal design: select a single- or double-seal arrangement and material that closely fits the plastic or rubber sheath and limits dust, water and gas ingress.
Retention: a flexible cable can move under pull or vibration. Choose an appropriate threaded or elastic clamping method based on outer diameter and vibration, providing enough grip without crushing the sheath.
Insulation: where additional electrical separation is needed, consider an insulating bush so metallic gland parts cannot contact conductors and create leakage or short-circuit risks.
These cables use one or more metallic screens, such as copper braid or aluminium foil, to limit incoming electromagnetic interference and radiation from internal signals. They are common in communications, control and measurement systems.
Screen continuity: an EMC gland needs a reliable electrical connection to the cable screen, using a suitable grounding contact or conductive element so the screen does not become discontinuous.
Material compatibility: match the gland material and surface finish to the screen to avoid galvanic corrosion and poor contact. Nickel-plated brass can be suitable for copper screens; aluminium screens need compatible contact materials.
Seal and screen: evaluate the grounding arrangement and sealing system together so one does not compromise the other.
Flat cables save space and simplify routing in equipment and moving cable-carrier systems. Their cross-section requires a gland and seal shaped to fit their width and thickness, rather than a standard round-cable entry.
Interface fit: the passage through the gland should match the cable dimensions to avoid looseness or poor sealing.
Clamping and sealing: use a design such as symmetrical clamping pieces or resilient pressure plates to distribute force across the width and seal all sides of the flat cable.
Bending: the gland should not create excessive stress where a cable flexes repeatedly. Install it where an adequate bend radius can be maintained.
A flameproof enclosure is designed to withstand an internal explosion and prevent its transmission to the surrounding atmosphere. Select the cable gland for the gas group, temperature class and other equipment and area requirements.
Protection marking: the gland’s certified marking must match the installation and the equipment’s type of protection.
Body and flamepaths: materials such as nickel-plated brass or 316L stainless steel can provide the required strength. Threaded and other flameproof joints need the specified width, surface finish and clearance so flame cannot propagate through them.
Sealing and pressure: seals must maintain performance under the relevant explosion and external environmental pressures, with suitable ageing and high-temperature resistance.
Increased-safety equipment uses measures such as better insulation, controlled surface temperature and reliable connections to avoid arcs, sparks and excessive temperatures in normal service and specified abnormal conditions.
Ingress protection: choose a rating, such as IP66 or IP67, appropriate to dust, moisture and water exposure at the installation site.
Temperature: gland materials and construction must be compatible with the equipment’s temperature class. For example, the source cites a 135°C maximum surface temperature for T4.
Connection integrity: secure terminations and orderly conductor routing help avoid high contact resistance, loosening, heating, sparking and abrasion.
Nylon is light, relatively inexpensive and corrosion resistant. It is often selected for less demanding, dry indoor areas without aggressive gases. Its electrical insulation is useful in low-voltage control circuits. The article notes resistance to many acids, alkalis, salt solutions and organic solvents, while also noting that high temperature, ageing and high mechanical stress can limit its suitability.
Nickel-plated brass combines brass conductivity with a corrosion-resistant surface and good mechanical strength. It can support electrical continuity and grounding while resisting oxidation. Typical applications include damp locations and moderate mechanical loading. However, aggressive chloride- or sulphide-rich environments may attack the nickel layer, so suitability must be checked.
316L is a low-carbon austenitic stainless steel used for demanding marine, chemical and oil-production environments. The article highlights its resistance to seawater, chlorides and various acids, as well as its elevated-temperature performance, strength and impact resistance. It is presented as a material choice for corrosive, high-temperature or high-vibration installations.
Metric threads use millimetre dimensions and are widely used in Europe and Asia. Common entry sizes include M12, M16, M20 and M25. Select a size matching the equipment entry and cable diameter. Sealing depends on the correct threaded fit and any specified washer, ring or other sealing method.
NPT is a US tapered pipe thread with a 60° profile and a 1:16 taper, commonly used in North American equipment. Its tapered engagement provides a pressure-resistant connection; sealant or tape may also be specified for some applications. Typical sizes include 1/8, 1/4, 3/8, 1/2, 3/4 and 1 inch NPT. The article identifies NPT as a common choice for oil, gas and chemical installations and North American projects.
G is a parallel pipe thread with a 55° profile. Because it is not self-sealing, a suitable O-ring or gasket is normally required. Common sizes include G1/8, G1/4, G3/8, G1/2, G3/4 and G1. It is used in various lower-pressure equipment connections, including European installations.
The source article states that metric and NPT, rather than G, are used as flameproof threaded joints under the ATEX and IECEx schemes and therefore does not recommend G threads for flameproof equipment. Always confirm the actual certificate and equipment-entry specification.
EAC addresses technical-regulation requirements in Russia and other Eurasian Economic Union markets, including Belarus and Kazakhstan. The article cites TR CU 012/2011 and TR CU 020/2011, and describes product testing and factory assessment through an authorized body before market placement.
IECEx is an international conformity-assessment scheme based on the IEC 60079 series for equipment used in explosive gas and dust atmospheres. It covers design, manufacture, testing and certification and can reduce duplicate assessments across participating markets; local market requirements still need to be checked.
ATEX applies to equipment intended for potentially explosive atmospheres in the EU under Directive 2014/34/EU. Selection must account for the relevant atmosphere, equipment group and category, temperature class and protection marking. Applicable products carry CE and Ex markings.
UL certification addresses relevant North American safety standards for hazardous locations. The source cites UL 1203 and UL 1604, covering aspects of materials, construction, electrical safety and explosion protection. Check the specific certification and whether it is accepted in the destination jurisdiction.
INMETRO certification addresses applicable Brazilian technical and safety requirements. The article describes testing and factory assessment by a Brazil-recognized certification body before sale of relevant explosion-protected equipment and cable glands.
China Compulsory Certification applies to products within the relevant regulated scope. Explosion-protected electrical products are assessed against applicable GB 3836 standards, including GB 3836.1 (general requirements) and GB 3836.2 (flameproof enclosure “d”). Verify whether the particular gland model falls within the compulsory-certification scope and holds the required certificate.
DNV approval is relevant to maritime and offshore projects. It addresses suitability for demanding marine conditions such as corrosion, humidity and vibration, with the product’s protection and ingress ratings checked against the applicable maritime requirements.
Sealing rings: provide the cable-to-gland seal against dust, water and gas. Select a ring suited to unarmoured, armoured or screened cable construction as required.
Washers and gaskets: metallic copper or stainless-steel washers may support mechanical connection and sealing in higher-load applications; rubber or PTFE gaskets provide insulation and sealing where specified.
Grounding terminals: bond the cable screen, armour or equipment enclosure where required to dissipate static charge and support electromagnetic compatibility. The connection should be conductive, mechanically secure and reliable.
Clamping components: armour rings, clamping bolts and related parts retain armoured cables under tensile load and vibration. Match their material, strength and corrosion resistance to the gland body.
Dust caps: protect unused gland openings from contamination before cable installation. Use a compatible cap to keep the entry clean and maintain connection reliability.
Evaluate these seven factors together against the actual application and project specification. Consult a qualified supplier for product data, certification documents and selection advice so the completed installation remains safe and reliable.
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