Burying electricity cables is common practice when laying cables within urbanised areas. Placing the direct-buried cables underground reduces disruption during construction and lowers the risk to members of the public. However, it does provide a number of risks for future excavation and third party digging.

In 2010, the dangers of not correctly marking or tiling buried electrical cable were unfortunately brought to light when a construction worker received severe burns to his face, neck and arms after the tip of the ground breaker he was using pierced through a 11kV cable buried around 80cm underground. The tool tip vaporised in a surge of at least 1 million watts causing injury to the worker.

Even recently, in March 2014, a digger bucket came into contact with a 20kV underground electric cable during excavation works in front of a newly built substation. Fortunately both workers avoided injury, but it was a serious enough incident that is sparked a HSE investigation. Andrea Robbins, HSE investigator of the case digger case, stated:

“The construction industry needs to be more aware of the dangers of working in the vicinity of live underground services.”

“Appropriate planning and control measures should always be in place. A failure to do so could result in inadvertent contact with the live cables, the consequences of which can be fatal.”

The dangers of burred cables are well known throughout the industry and products have been developed to reduce the risk to workers unknowingly disrupting electricity supply and risking injury or death. ETS provide a number of different buried cable marking and tiling products from concrete tiles to heavy duty 60micron thick plastic tape tile to aid with the identification of underground cables.

Our vast range of products provide a number of different advantages, not least protecting and reducing the risk of injury and loss of life. Correctly marking cables can help reduce the risk of loss of power supply for end users and tiled cables can improve the impact resistance of the cable to reduce damage during localised digging and disruption.

Using cable markers to identify and protect underground electrical cables offer a significant cost benefit when compared to the time and cost of replacing damaged or severed sections of the cable.

We also supply a traceable underground warning tape which features two stainless steel wires running through it to enable detection by metal detectors prior to any digging, enabling any alterations to be made before work begins.

Ultimately, taking precautions when burying cable can help save time and money during future projects and it could even safe someone’s life.

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

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.

Extruded Brass Bar	Honey Brass

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!