Effective lightning protection involves the integration of several concepts. nVent ERICO employs the Six Point Plan of Protection as a useful guide to ensure the highest level of system security.

1. Capture the lightning strike

Capture the lightning strike to a known and preferred attachment point using a purpose-designed air terminal system.

2. Convey this energy to ground

Conduct the energy to ground via a purpose-designed downconductor.

3. Dissipate energy into the grounding system

Dissipate energy into a low impedance grounding system.

4. Bond all ground points together

Bond all ground points to help eliminate ground loops and create an equipotential plane.

5. Protect incoming AC power feeders

Protect equipment from surges and transients on incoming power lines to help prevent equipment damage and costly operation downtime.

6. Protect low voltage data/telecommunications circuits

Protect equipment from surges and transients on incoming telecommunications and signal lines to help prevent equipment damage costly operation downtime.

If you found this article helpful or interesting, please share it!

We have all become accustomed to the flood of supposedly ‘economy’ range of products from manufacturers in the electrical supply industry, which often come at a competitive price that seems good to be true. Unfortunately, this can often be the case and by using these products you may be taking serious risks with the integrity of your cable installation.

The electrical contracting industry is more competitive than ever and efforts are always being made to improve margins and reduce costs, however many suppliers are providing cheap, sub-standard products in order to make themselves more competitive.

As a supplier of cable glands from a number of reputable manufacturers such as: CMP, Hawke, and Prysmian – we have carried out research over the years to ensure that quality standards are adhered to, allowing us to provide products with extended warranties. This protects both our reputation as a supplier and hopefully yours as a contractor of quality installations.

Our research has highlighted some of the following points worth bearing in mind:

– Cable Glands are covered by European Legislation, supplying glands that do not comply with the standards is contravening legislation.
– Many wholesalers and distributors are unaware of this, they may not realise what they are selling does not meet the relevant safety standards.

What problems can occur with Cable Glands?

There are three main factors affecting the safe performance of a cable gland, these include:

– Integrity of mechanical design
– Quality of materials used in manufacturing
– Degradation of seals over time

The tests contained within the current standard BS:EN50262 are designed to ensure that the product is of sufficient, robust mechanical design to enable it to withstand continuous shearing forces at the point of entry into the equipment and that the cable is adequately retained by the seals and/or armour clamp.

Sealing materials also vary greatly in their ability to withstand attack from airborne pollutants and environmental elements. Reputable manufacturers test their seals to withstand prolonged exposure to these risks.

Always check that your supplier can supply Third Party Test Reports that confirm these essential requirements, if they are unable to provide a test report, you should be aware that these products may not meet the required European legislation.

Brass is Brass?

A cheap inferior gland may, at first glance, look and feel very similar to a high-quality cable gland, but the quality of the brass used to make it can fluctuate greatly. Raw materials represent a significant cost in the cable gland manufacturing process, and due to the fact that extruded brass is a globally-traded commodity, the country of origin has a relatively small impact on the finished gland cost.

Typically, poor quality glands are manufactured from “Honey” brass, which is melted down and recast scrap metal, full of impurities and air voids which undermine the strength and integrity of the finished product which, over time, could lead to threads shearing or glands literally falling apart.

In some cases, the gland may rust after only a few years of use, implying a high ferrous metal content within the brass used in their manufacturer.

Actual case we have been called out to in the UK:

Choosing a gland to give you piece of mind

The first port of call should be checking if the product is CE marked. If it isn’t, you should have serious concerns about the risks you may be taking by buying or using these products. Even if the product comes with a CE mark, be aware of rogue manufacturers as the presence of the CE mark does not always mean the product complies.

If you have any concerns over the quality of the product you are buying, you should ask your supplier for the full CE Technical File, which will contain evidence of 3rd party testing and a detailed appraisal of the product compared to the prevailing standards.

Don’t damage your reputation

Unfortunately, often it is not until cable glands have been installed that quality issues come to light. Then it can be too late to avoid the potentially incalculable cost to your long term reputation, not to mention the short term cost on the job.

Should you require any further impartial advice on any of the above or if you would like to see further technical information, please do not hesitate to contact us.

If you found this article helpful or interesting, please share it!

Why do we use cable cleats?

Cleats are an often under estimated component of cable management systems, principle they exist to fix, retain and support cables. In addition, where short-circuit faults are anticipated, correct cleating will result in the containment of the cables during a fault and enable the circuit to continue operation with the minimum disruption.

What type of cleat do I need to use?

We currently offer over 25 different types of cleats to suit various installation requirements. These range from our single and two bolt LSF cleats, through to Emperor stainless steel cleats, designed for installation within extremely harsh environments throughout the world, e.g. off-shore petrochemical plants.

In the UK, the majority of commercial and industrial contracts call for the use of LSF cleats, aluminium two-part single way and trefoil cleats, along with the increasing use of stainless steel cleats, particularly since the advent of Fire Performance cables for critical circuits.

The following questions need to be answered to ascertain the relevant cleat for any given installation:

– What is the conductor size?
– What type of cable? i.e. single core, multi-core, XLPE, unarmoured, steel wire armoured, aluminium wire armoured etc.
– What is the overall diameter of the cable?
– Does the specification call for a specific type of cleat or type of material?
– Does the specification call for any fault current requirements?

Common issues and questions raised when ordering cleats:

– Preference for using cables ties to save money, instead of cleats.
– Spacing requirements, i.e. ladder-rack not being wide enough to accommodate the required number of cleats.
– The short-circuit withstand required from a cleat when installing single core AWA cables.
– Suitability of cleat to a particular cable, e.g. Fire Performance cleats to suit FP400 cables.
– Other spacing issues, such as the recommended mounting distance between cleats when installing cables vertically being different from when the same cable is being installed horizontally.

ETS Cable Components are the UK’s leading stockists and distributors of cable cleats and cable management accessories. For more information on our range of cleats, visit our cable cleats page or contact our Sales Team.

If you found this article helpful or interesting, please share it!

The safe and correct working of accessories used for cable terminations is dependent upon many issues from the correct specification of the product through to competent installation. The following is a list of (maybe obvious) do’s and don’ts which should be adhered to.

The “Do’s” of Cable Terminations

– Do ensure the correct products are specified – such as ColdShrink, Heatshrink or Screened Connectors.
– Do check associated products are compatible and safe to be used together.
– Do check the accessories and cable dimensions match.
– Do ask the manufacturer or distributor for more information on the product is required.
– Do prepare the cable and accessories in a suitable environment (clean and dry).
– Do ensure all staff are trained and competent to carry out the termination.
– Do use the correct tools for the job.
– Do ensure these tools are properly maintained and functioning properly.
– Do make sure the cable lugs/terminals are installed correctly – for crimp connectors, ensure the correct die sets and compatible tooling.
– Do smooth any sharp edges on lugs caused by crimping dies.
– Do read and follow installation instructions carefully.
– Do not forget to install the earthing system correctly.
– Do ensure heat shrink and cold shrink components are correctly positioned before shrinking or removal of cores.
– Do fully test the terminations after installation.

The “Don’ts” of Cable Terminations

– Don’t rush any part of the job.
– Don’t cut corners or take short cuts.
– Don’t allow sheds on adjacent cores of a three-core termination to touch – This can lead to discharging.
– Don’t allow any secondary wiring to be damaged when installing heat shrink sleeving.

If you found this article helpful or interesting, please share it!

Single-core power cables can be run in a number of formations, the most common include flat or trefoil formations. Each cable formation has its benefits and drawbacks, we’re going to look at the differences between each way for laying these cables.

Trefoil Phase Formation

One of the main reasons trefoil formations are used is that it places the phases the same distance apart, so the magnetic field and circulating currents are equivalent for each cable phase. Typically, trefoil phase formation is more commonly used for Low and Medium Voltage applications up to 132kV due to ease of installation and the reduction in space the formation has across the containment system used. However, installing single-core cables in trefoil formation can mean that the touching cables will exhibit worse heat-dissipation when compared to flat formation, therefore lowering the current-carrying capacity. Considerations which should be taken into account by specifying electrical engineers when designing such systems.

Flat Phase Formation

Rarely used at voltages below 275kV due to the mounting centres having to allow for sufficient heat-dissipation. Running in flat formation, the central phase of the three-phase set is adversely affected by the magnetic fields around the neighbouring phases, leading to a higher running temperature on the middle phase and subsequent voltage imbalance. Phase transposition can be used to counter-act these affects, but the necessary mounting space required for such installations usually precludes their use in most industrial/commercial installations and flat formation tends to only be used by major DNOs in their distribution networks.

Trefoil formations are chosen for applications where space is at a premium and flat formations also tend to be less cost effective due to the increase potential cable route space they take up. Our experience of such installations has generally been with cables above 132kV, with cables under 132kV being laid in a trefoil formation.

Triplex Formation

An adaptation of the trefoil formation can be found with the increasingly popular Triplex formation. Triplex cables are three conventional single-core cables supplied pre-wound in trefoil formation by the cable manufacturer/vendor, the three cores having been slowly twisted together during the manufacturing process and supplied on one drum, offering significant benefits in installation time.

Due to the constant phase rotation of the cores, using conventional trefoil cleats is not possible as the position of the mounting base will not be constant. For this reason our Triplex Cable Former provides a cleating solution, allowing traditional trefoil cleats to be used. Learn more about our offer of power cable lugs.

Cable cleats suitable for each cable formation:

If you found this article helpful or interesting, please share it!

Flexible conduit systems can provide a proven safe and cost effective protection solution for cabling installed in explosive atmospheres. Better safe than sorry is a sensible approach, but make sure that you are not fooled into unnecessarily expensive options warns Tim Creedon, Sales and Marketing Director for Flexicon.

Explosive areas exist where a flammable mixture of gas and air or dust and air exist in large enough quantities and for long enough. If an ignition source exists then there is a real danger of an explosion.

Naturally we all think of the oil and gas industry in such situations, but there are a surprising number of other industries where explosive atmospheres could exist such as in building and construction, transport, marine and defence, food processing, water treatment and power generation to name but a few.

Wherever possible it is important to minimise the risk of explosive mixtures forming and/or prevent the risk of ignition. Where this is impossible or impractical then you need to consider providing protection.

Any electrical installation in such an environment is a potential source of ignition. The degree of protection any equipment requires depends to a large extent on the risk of an explosion occurring in a given area.

To understand the level or protection required, you must understand the nature of flammable mixtures and ignition sources and also how different zones are classified depending on the level of risk.

Gases are classified into 3 groups with group A being the least explosive and group C being the most. Equipment classification is from T1 to T6 according to the maximum allowed temperature resulting from the ignition temperatures of the gas/air mix. It is important to remember that certain fine dusts dispersed in the air can also be explosive.

Hazardous Zones

The above table shows the zone designations, which are divided first into the hazardous areas for gases, vapours and mists and secondly into the hazardous areas for dusts. It also shows their risk categories, i.e according to the probability of a risk being present.

Assuming that the electrical equipment is correctly specified, it is important not to overlook any cabling that connects into it.

Until recently those specifying cables for such areas had to select from the products offered by various cable manufacturers. In addition each individual cable needed a flameproof gland, which added to both the cost and the time needed for installation.

Such cables could also be difficult to terminate and, if a number need terminating in an enclosure, could necessitate the specification of a larger enclosure.

The development of flameproof ATEX and IECEx approved barrier glands for flexible conduit means that you can use liquid tight conduit systems in hazardous areas without compromising safety.

There are a number of ways of classifying protection techniques used to address hazardous zones. Most glands are classified as Ex d or Ex e.

An Ex d classified gland forms a flameproof or explosion proof barrier – they are strong enough to contain any explosion or fire that may occur. An Ex e classification is defined as ‘increased safety’.

If something is classified as Ex d then it can also be used for Ex e applications in Zone 1 and Zone 2 areas for gases and Zones 21 and 22 where explosive dust may be present. In most cases such glands do not add to the temperature of the enclosure into which it terminates, so it can be used with all temperature classes.

By using Ex d glands with liquid tight conduit, you can group several cables together into one system. The conduit provides protection for all of these cables and, if correctly selected, offers all the necessary mechanical protection for a given application.

So, for example, by using steel cored armoured metallic conduit you might be able to use standard cables instead of more expensive SWA specialist cables. In this example one braided conduit effectively takes the place of several more expensive braided cables. It also means that only one flameproof barrier gland is needed, rather than several.

This single termination, instead of the multiple terminations that would be needed with individual cables, limits the risk of the enclosure integrity being compromised since there is only one point of entry. Using a flexible conduit system also provides additional mechanical protection for the cables.

It is worth pointing out at this stage that it is the flameproof gland that is rated at Ex d so that if there were an explosion within the electrical equipment enclosure it would be contained. Some conduit manufacturers have in the past muddied the waters and inferred that the conduit is also classified as Ex d and been able to charge a premium.

The role of flexible conduit in any application is to protect cabling so you should take care in its specification. This is even more important in hazardous areas since you want the installation to remain safe throughout its lifetime, not just once the system is installed.

Fortunately when you specify the correct barrier gland, you can effectively use a liquid tight flexible conduit for the vast majority of applications.

There are a number of different types of liquid tight flexible conduit that are suitable for both indoor and outdoor applications.

With this in mind the specifier needs to conduct a thorough risk assessment of all of the hazards potentially faced by the conduit in addition to the explosive atmosphere.

From this risk assessment they can then accurately specify the most appropriate liquid tight conduit for the project. As an illustration Flexicon has eight different grades of liquid tight conduit which, between them, would suit most applications.

Other environmental factors

If conduit is left in an exposed situation, it could be crushed or there is a chance that something could be dropped onto it. For such applications you should specify conduit with an adequate compression and/or impact strength.

Other factors that you may need to consider when selecting the correct conduit might include: extremes of temperature, EMC screening requirements, moving equipment, abrasion, resistance to chemicals or corrosion and UV resistance for external installations.

Note this list is not comprehensive, hence the need for a full risk assessment. If you have any concerns then most manufacturers should be able to advise.

A great deal of attention has been paid to hazardous area equipment. Do not forget cable protection and electrical lugs.

For more information on our range of Flexicon flexible conduits, please contact our Sales Team.

If you found this article helpful or interesting, please share it!