Sealed cable gland. Entry of cables into the building What is cable entry for?

We often come across the following opinion of customers: “The type of cable glands used is not fundamental for us, the most important thing is that they have the appropriate certificates and permits. Contractors should be responsible for selecting cable glands. Our challenge is to make complex technological and manufacturing decisions that provide maximum efficiency, so that we can worry about choosing such small parts. "
At the Hazard Ex Conference on Equipment for Hazardous Areas, the Senior Manager of the Bureau of Standardization CENELEC presented papers that listed the most common issues requiring priority funding. These include:
1. Unauthorized modification of devices;
2. The use of enclosures and cabinets with poorly manufactured or inappropriate cable glands;
3. Corrosion.
The document went on to state that, in addition to these three factors, the most common mistake is incorrect installation of cable glands. Although the document focused on the tasks encountered during operation, this statement is completely true for new installations.
Incorrect installation and technical parameters of cable glands, together with the inability to check the reliability of the gland seal in working order, can lead to failure technological equipment and corrosion of the armor and cable sheath. And the threat to safety, as well as possible production losses, are generally immeasurable.
Even this argument alone is a sufficient justification for the necessity and importance of making a decision on the choice of cable glands. Simply relying on the fact that the cable gland is certified for this category of application is not enough.
What to look for when choosing cable glands?
Certification
Of course, it is very important to select the correct type of cable gland and check that it has a certificate corresponding to the hazard category of the area in which the equipment is supposed to be used. Our company provides catalogs with full technical information about the bushings and a special program that allows the user to independently go through the procedure for determining the type of cable gland step by step. If you are in doubt about the result, our technical specialists will be happy to advise you. But it must be borne in mind that the mere fact that a cable gland has a certificate corresponding to the category of hazard of use is not enough to select it.
Moisture penetration.
One of the most important characteristics of cable glands is to prevent moisture from penetrating not only into the equipment, but also into the armor clamping compartment inside the gland itself. The penetration of moisture into this area leads to catastrophic corrosion of the armor and braid and the associated costs of laying new cables and losses from downtime. The IP rating indicates the degree of protection against the ingress of moisture and dust into the equipment, but not necessarily into the cable gland itself.
DTS01

In 1991, Shell UK recognized that IP rating was not necessarily sufficient to meet the harsh operating conditions found in most hazardous area applications and developed the more stringent DTS01 test to eliminate the possibility of moisture ingress due to temperature cycling and when flooded. Our products have passed Shell's DTS01 test under even more severe conditions. The received DTS01 certification guarantees protection against moisture penetration into the clamping area of ​​the Hawke cable gland armor using a moisture-proof seal. This property is of fundamental importance when choosing cable glands. Not all manufacturers of cable glands have test certificates confirming protection against moisture penetration into the clamping area of ​​the armor, or covering the entire operating temperature range for which the glands were certified.

Seals.
Cable gland seals have two functions:
Prevent explosion products from entering the surrounding atmosphere in the event of an explosion inside the enclosure shell;
Prevents water and dust from entering the equipment housing and the cable gland itself.
Seal materials
Manufacturers of cable glands use different materials for the manufacture of seals, which can be roughly divided into two categories:
Thermosetting (TSE). This category of materials cures during the molding process when exposed to heat and pressure. Once molded, this type of material does not "melt" and exhibits optimum sealing performance over a wide temperature range.

Thermoplastic (TPE). Despite the lower cost to the manufacturer compared to TSE seals, materials of this type are susceptible to "melting" when exposed to temperature, and their sealing properties deteriorate with increasing temperature. Thermoplastic materials are ideal for key and handle applications, but are not recommended for use as seals in critical environments.
TSE is more suitable for cable gland applications and is therefore the only material Hawke uses for a wide range of compression and diaphragm seals for all cable gland models.
During the compression (ability to recover after deformation) test, the test specimen at elevated temperatures is compressed in a special clamp to 25% of its width and remains in this state for 3 days. The sample is then removed from the clamping device and allowed to recover at ambient temperature. The amount of compression "shrinkage", equal to the difference between the initial thickness of the sample and the new one, expressed in%, is one third less in good quality TSE materials than in TPE materials. High Quality.
TSE is characterized by better resistance to aging, in particular to ozone, ultraviolet rays, oxidation and weathering; as well as incomparably high oil and chemical resistance. TSE also has a higher temperature resistance. For example, the maximum operating temperature for silicone TSEs (used by Hawke for rear seals and diaphragm seals for 453 / Universal cable glands) reaches 300 ° C (intermittent exposure), while most TPE materials soften significantly already at 100 ° C. Silicone is effective at -60 ° C, while the highest quality TPE materials can work down to -40 ° C. TSE is also characterized by a higher fire resistance, and silicone has additional advantages: it practically does not smoke when burning and does not emit halogens at all.
Tolerances in cable size and construction.
Significant costs for cable used in hazardous area projects often result in reduced cable requirements. Hawke International cable glands use a special rear-end sealing system that allows for a wide range of cable deflections, allowing for diameter variation along the cable, and eliminating the need for special additional outer sheath seals.
Cold flow characteristic

In accordance with IEC 60331 and IEC 60332, some cables have additional requirements for fire resistance and flame retardancy. Most cables of this type have the characteristic of "cold flow" of the cushion of the inner sheath. This means that when a certain pressure is applied to the shell, for example, caused by the compression of the inner shell by a compression-type seal, the material with these properties spreads, which leads to a violation of the sealing efficiency. Clause 9.1.3 UK Building Code EN 60079-14: 1997 / IEC 60079-14: 1996 prohibits the use of compression-type cable glands for cold-flow cables. Hawke's 501/453 / Universal Cable Gland has a diaphragm-type inner sheath seal that fully complies with the Building Code requirement above and exerts minimal pressure on the inner sheath of the cable gland. The seal does not damage the cable sheath material ("cold flow"), but maintains the appropriate IP and explosion protection class.
Why is it important to choose the right type of cable glands?
Correct installation.

Only special training of the technicians can guarantee the correct installation of the cable glands. Major global contractors and contractors are monitoring professional level of its employees, and in most cases it is a mandatory requirement to obtain a certificate of recognized authoritative courses, for example, CompEx. However, this requirement is not mandatory in all countries. Therefore, it is very important that the assembly procedure for the selected type of cable glands is simple enough, for each cable gland it is attached detailed instructions the assembly and the tightness of the seals could be easily checked at every stage of the assembly. Hawke International's cable glands are designed with a minimum number of components, making assembly quick and easy.
Enhancing security with validation.

Safety is a priority in hazardous area installations. Security depends on many factors, some of which have already been listed in this article. The ability to inspect equipment also plays a key role in ensuring safety.

Is it possible to check all the characteristics of the cable glands after installation using simple procedures? Hawke cable glands are designed to answer YES.

All Hawke cable glands can be quickly and easily disassembled and visually inspected for a secure grip on the armor clamp. Moreover, the 501/453 / Universal cable gland allows inspection of the inner seal of the cable sheath, and the ICG 653 / Universal is the only barrier type gland that allows full inspection and, if necessary, repair of the cured compound without destroying the cable gland. Moreover, you can check the sealing system of the rear of the bushing and the moisture-proof seal during operation.
Why is it important to choose the right type of cable glands?

If you are interested in safety, reliability and reduced operating costs by reducing downtime and production losses, then you just need to take the time to determine the parameters and characteristics of the cable glands that are optimal for your application.
The main parameters that determine the choice of cable gland.
Summing up, we will list the main parameters to which you need to pay special attention when choosing the type of cable glands.

The most common mistakes encountered in hazardous area installations are choosing the wrong type of cable glands or installing them incorrectly.
Will the certified cable gland meet all application requirements?
Please note that not all cable gland specifications are covered by standard certification requirements.

Will the selected type of cable gland meet the requirements for dust and moisture penetration?

Does the cable gland have a DTS01 test certificate confirming that the cable gland is protected against moisture penetration into the equipment body and the armor clamping area?
Does the cable gland seal have a long service life? And is it capable of providing protection against moisture penetration under periodic temperature exposure and other harsh conditions at the installation site?
Is the Thermoset (TSE) material best suited for this function for the seals?
Does the cable gland allow a wide variation in the cable diameter without the need for special additional outer sheath seals?
Is the cable gland suitable for use with cold flow cable and is it in accordance with BS EN 60079-14 1997 / IEC 60079-14 1996 Clause 9.1.3?
Is it easy to install? Does the cable gland have clear and simple assembly and installation instructions?

Does the cable gland allow for a secure seal and tightness test after assembly?

Cable glands or cable glands are used to secure the cable and seal the entry point into the electrical enclosure or containment for piping. Often, this connecting element is considered insignificant and does not pay enough attention to its selection, or they pay it mainly to cost. This approach is erroneous and can lead to serious consequences.

In addition to the main tasks indicated above, cable glands perform a number of other important functions:

• protection of cables and equipment from external influences (moisture, dust, etc.)
• ensuring the tightness of the case when used in an explosive environment;
• prevention of breakage of the connection due to mechanical stress on the cable.

The use of low-quality cable glands often leads to temporary inoperability of electrical equipment due to the lack of contact or its failure as a result of the ingress of foreign particles into the case, as well as to the occurrence of fires and others. emergency situations... As a result, insufficient attention to small details entails big troubles, especially when it comes to a large and responsible object or technological process.

Careful selection of cable glands in terms of parameters will minimize the risks of emergencies at the facility and increase the safety of technological processes. The use of original certified components also helps to reduce operating costs by reducing equipment downtime and the resulting reduction in production.

Selection of cable glands

In order for the cable glands to ensure the fulfillment of all the tasks assigned to them, it is important to select them correctly in accordance with the operating conditions, the type of equipment and cable on which they will be installed. In this case, it is advisable to adhere to a certain algorithm.

The main criteria for the selection of cable glands:

1. Cable type (armored or unarmored).
2. Method of cable laying.
3. IP protection class.
4. Operating environment.
5. Existence of requirements for explosion protection.

Currently, manufacturers of cable glands produce a wide range of products that differ in a number of characteristics:

• body material;
• sizes;
• type of seal;
• type of connection;
• the level of protection;

This allows you to select the most suitable product for a particular case in compliance with the requirements, eliminating unreasonable costs. It should be borne in mind that the current regulations and standards do not cover all the characteristics of cable glands. In this regard, some companies apply their own design solutions and innovative materials in order to improve the quality of products and their service life in difficult conditions. Preference should be given to products with additional advantages.

The need to use a cable gland arises every time we need to protect the place of cable entry into the sheath from moisture or aggressive media, be it a junction box, an electric motor or an electrical panel. Particular attention is paid to this in industry, where there are aggressive environments and explosive areas.

The first thing to start with is to find out the brand and cross-section of our cable, to determine in which zones the cable gland will be used: explosive or not.

Let's consider the situation for explosive and fire hazardous zones.

There is a VBShvng (A) 3x2.5 cable and an explosion-proof junction box with an M25 threaded hole for a cable gland.

1. The cable gland must be suitable for the hazardous area and the enclosure or equipment on which this cable gland will be installed.

Since the cable gland is an explosion-proof component (Ex-component), the type of protection of the Ex-component must correspond to the explosion-proof marking of the enclosure or equipment. Details about this are written in GOST R IEC 60079 or can be found in the article on the application.

Another important point is that the explosion-proof cable gland must be certified by TR CU 012/2011.

2. For which cables the cable gland will be used: armored, not armored. Our cable is armored.

3. Type of cable armor - tape, multi-wire. We choose the option with a steel tape.

4. Select the material for the cable gland. Can be steel, brass, brass with nickel, stainless steel, plastic. When choosing a material, you need to be guided by the aggressiveness of the environment and the price.

5. Determine the type and size of the thread for the cable gland. The thread can be metric, tapered, inch. For our case, the size of the thread is M25.

6. Determine the size of the cable glands. According to the reference data, we find the outer diameter of the armored cable and the inner diameter (the diameter of the cable without armor). Outside diameter 13 mm, inside diameter 11 mm. Our sizes must be within the acceptable range.

7. Seal material. Typically, manufacturers offer two options - silicone and neoprene. Differences in the range of ambient temperatures used. Silicone works from +120 to -60 C, neoprene only from + 20 C (approximate data).

8. Determine the set of required accessories for the selected cable gland: lock nut, grounding ring, lug for connecting a metal hose, etc.

To select cable glands for general industrial equipment, it is sufficient to apply the above algorithm, excluding the first item from it.

The modern world cannot be imagined without various electrical appliances. They facilitate our work, help automate some processes, monitor various indicators in real time. The heart of any device is printed circuit board, with located on it electronic components, connectors and modules that are susceptible to mechanical stress and the environment. A sealed housing is used to protect them, and cable glands are used for external sealed connections.

Junction box with connected cable glands

Components

Components of the cable gland:

• frame,
• spade cable clamp,
• cable gland,
• union nut,
• thread seal
• counter nut.

The seals provide the required degree of protection against the ingress of moisture and solid particles. The union nut secures the cable with a lug clamp. With a counter nut, the seal is clamped on the device body or simply screwed in, if a threaded hole is made in the body.

main parameters

The main parameter is the cross-section of the cable to be clamped. There are entries for thin cables (1-3mm) and large diameter cables (up to 70mm). The next important parameter is the degree of protection against penetration (dust-moisture protection). It happens in the range of IP54 (without protection against external influences) - IP68 (protection against water jets at a depth of 1 meter). Of the electromechanical characteristics, the main ones are: the maintained pressure difference, without loss of tightness (usually up to 5 Bar) and the operating temperature range (depending on the material of manufacture and the type of sealed gland, it can be from -60 to + 100C)

Cable gland thread type:

• M - Metric threads, standard M12-M63 (but there are series with non-standard sizes threads from M6 to M100
• PG - Inch thread, standard PG7 - PG48
• NPT - Pipe threads, standard 1/2 '' to 4 ''

Range

Today the assortment of cable glands, glands and sealed glands is extensive and includes hundreds of models and thousands of modifications.

Plastic cable glands

The most common are standard plastic glands. The material of manufacture of such glands is polyamide 6. Also, the cable gland can be made of fireproof polyamide 6, certified according to the fire safety class V0-UL94. The cable gland is made of TPV (Thermoplastic Vulcanizates), the thread seal is a NBR rubber ring (NBR) of round or flat section.

Selection of plastic sealed glandsOrtac

On the inner side of the union nut, special notches can be made to prevent loosening from vibration loads. Such glands are capable of providing a high degree of protection up to IP68, protection against oils and alkalis.

Metal cable glands

By design, standard metal glands do not differ from plastic ones. The housing of the cable gland and union nut is made of metal:

• Nickel-plated brass Grades MS58 (brass 58%, zinc 52%) / MS63 (brass 63%, zinc 37%)
• Stainless steel . The ASIS 300 series is used (Chrome-nickel stainless steel, the most versatile). They also use the ASIS 400 series (stainless steel with a high chromium content - retains its properties in corrosive and sulfur-containing environments, resistant to sudden temperature changes)

Metal cable glands and accessories

Typically, metal cable gland seals are NBR and TPV, but there are series of metal cable glands with silicone seal. Polyamide 6 lug clamp is used as standard in the metal cable gland.

Varieties and types of cable glands

A separate category of metal bushings for use in hazardous areas. The key purpose of the sealed lead-in in such conditions is not to protect against explosion, as it might seem at first glance, but to prevent the penetration of flammable gases into the device. The sealed lead must not allow gas leakage between the seal and the cable sheath. Consists of a body, a union nut, one or two cable glands, a thread seal and a counter nut.

EX and accessories

In Russian practice, explosive zones are divided into several types, depending on the presence of a highly flammable substance or dust in this zone, which forms an explosive mixture with air.

Zone 0 (Zone 20) Explosive gas (dust) present continuously or for a long time

Zone 1 (Zone 21) - Explosive gas (dust) is not permanently present, but is likely to occur under normal operating conditions

Zone 2 (Zone 22) - Explosive gas (dust) can only appear as a result of equipment errors or breakdowns and is present for a short time

Varieties

• Cable gland for armored wire with double seal
• Cable gland for armored wire with one seal
• Cable gland for unarmoured wire, standard
• Cable gland for unarmoured wire for pipe systems
• Cable gland for armored wire with flat nut.

To operate bushings in explosion-proof conditions, they must be certified according to international (ATEX standard) and Russian (compliance technical regulations TR CU 012/2011) requirements.

The functionality and capabilities of cable glands can be expanded through the use of various accessories:

• Threaded / cable plug, is inserted in place of the cable gland in the junction box to cover the opening. Retains the IP of the instrument case without a cable gland. If necessary, it can be quickly dismantled / the plug can be made of polyimide or metal.
• Counter nut with and without collar, polyamide 6
• NBR / TPV O-ring
• Reducers and thread adapters, nickel-plated brass
• For explosion-proof models are also used
• Threaded plugs with various heads, for a spanner, with a round head for a hexagon, recessed under a hexagon. (brass, nickel-plated brass or stainless steel)
• Threaded adapters and reducers (brass, nickel-plated brass or stainless steel)
• Protective cover, put on the cable gland for additional protection TPV, PVC, LSF
• Grounding contact, for cable glands for armored cable, brass MS64 nickel-plated or stainless steel

Accessories for cable glands

Major manufacturers of cable glands

As in most cases in the electrical market, manufacturers of cable glands are divided into 2 groups. Europeans set the technological pace, certify products and develop specialized solutions for industries. Colleagues from Asia skillfully copy all developments, avoid sanctions for patent infringement and offer more low prices... But there are exceptions.

Major European manufacturers:

• (Germany, main specialization - industrial and explosion-proof glands for hazardous areas. High price segment. Leading manufacturer on the market)
• (Germany, a large manufacturer of cables and wires and accessories for general industrial purposes. High price segment)
• Wiska(Germany, specialization in the standard line of cable glands. Adaptation of products for Russian GOSTs. High price segment)
• (Germany, The production of cable glands is placed in a separate division. All standard line of glands. High price segment)
• Bimed(Finland-Turkey. An apologist for solutions for the food and medical industry. Middle price segment)
• Ortac (Turkey, Full line of cable glands, including EMC, explosion protection, general industrial glands and Corrugation. In Russia, OrVent brand is actively developing - ventilation solutions for sealed enclosures. Despite the wide range and availability of the necessary certificates, they adhere to a low price segment - at the level of Asian counterparts )

CNC turning and milling machines for metal processing (left) thermoplastic machines for the production of plastic products (right) at Ortac

Major Asian manufacturers

(China, a standard line of sealed glands, the main feature is a wide range of sizes within standard models, including NPT threaded glands. Mid-price segment)

(Taiwan, in addition to the standard line, there are solutions for miniature metal sealed glands. Dear brand, high price segment)

IEK(De jure Russian, de facto - Chinese manufacturer of connectors and electrical components. Low price segment)

(China, a narrower range of bushings, mainly for junction boxes. Low price segment)

Cable glands are widely used in industry, in particular in such industries as lighting, security and safety, laying and installation of power grids, telecommunications. Metal models are used in heavy industry - oil and gas complex, shipbuilding. The variety of shapes, types and sizes allows you to choose effective solution for any task