Cabling and the invisible threat of non-compliance

Feature

6 March 2019

By Eland Cables technical authors

Since 2010, some 1.1 million homes have been built in England alone, with the number homes rising by 15% in 2017, according to the UK government. In London, Sadiq Khan plans to put £250m toward buying and preparing land for new and affordable housing.

And, growth is not restricted to the residential sector. The London Bridge station rebuild was a major focus in the capital, and a glance at the skyline shows a city constantly developing.

Powering all this is a busy construction industry, with a raft of materials and products underpinning every project, one of which is cabling. The quality of every construction depends on the quality of its cable, hence building firms need to ensure that the materials they source are truly fit for purpose.

There are British, European and international standards to define cable construction and performance, as well as clear rules for compliance.

Standards and Compliance

Various industry bodies are charged with keeping standards up to date and fit for purpose, and the specifications they publish are stringent to safeguard safety and reliability. The UK’s national standards body – the BSI (British Standards Institute) is part of CENELEC (the European Committee for Electrotechnical Standardisation) and is bound as a member to adopt its recommendations on top of the UK regulations, promoting uniformity in standards across the EU.

In July 2017, an EU regulation called Construction Products Regulation (CPR) came into force, which classifies newly-manufactured cables by their reaction to fire. Cables used for fixed installations must be tested for their flame characteristics and classified from A to F, with additional classifications for smoke emissions, flaming droplets and acidity.

However, despite the regulation and testing, it’s still estimated that up to 20% of all cables in circulation in the UK are either sub-standard, counterfeit or non-approved. For a commercial or industrial build, sub-standard cable can result in downtime, reliability issues and ballooning maintenance costs at best, and major safety hazards at worst. For residential projects, sub-standard cable can be a dangerous time-bomb to families and a major business risk for developers. As such, non-compliance is a huge threat and would jeopardise the industry’s ability to deliver.

In part, a big responsibility falls to the site developers and engineers to be vigilant and take a proactive stance. They play a key role in ensuring only compliant products make it onto site, ready for installation.

Up to Standard

The sheer number cable types and standards can be overwhelming, covering cables for power, data, control and instrumentation; low, medium and high voltage; armoured or fire-resistant; and covered in different materials that include PVC and Low Smoke Zero Halogen (LSZH) compounds.

RoHS Directive (the Restriction of Hazardous Substances) is a well-known and established Europe-wide legislation, designed to prevent products with high level of substances that can have a devastating impact on health enter the supply chain. These include lead, mercury and hexavalent chromium. Any cables sold inside the EU need to be RoHS-compliant and most are; however, it’s essential to be absolutely certain.

In addition, CPR and other standards determine the flame propagation (Vertical Flame Testing to BS EN 60331-1-2) and gas emissions of cables under fire conditions (BS EN 60754). For instance, PVC emits chlorine gas when burnt, which turns into hydrochloric acid when mixed with water from the atmosphere. It also produces a thick, light-obscuring smoke that can cause damage to sensitive equipment and risk safe evacuation of buildings. This is why Low Smoke Zero Halogen sheath materials are now mandatory for cables in public buildings and spaces in the UK. They emit low levels of toxic fumes, 60% less dense black smoke and no acid gases.

Regulating the Cable Supply Chain

Cable manufacture is now limited in the UK. The bulk of manufacturers of British and European standard cables are based in Italy, Spain, Portugal and Turkey, making policing standards and regulations harder.

Small changes to the raw materials going into the cable can have a huge bearing on the final product. For example, small reductions in the concentration of copper content in the conductor can have a major impact on the performance of the finished product; or the water used to mix with the pellets for the sheathing and insulation materials might have elevated levels of lead as a result of emissions from an upstream factory.

All of this is manageable, help prevent sub-standard, non-compliant cable from entering the UK supply chain. Sadly, that’s not always enforced to the degree it should be, meaning in most cases it’s not immediately apparent that the installed cable is non-compliant. It might be years before problems come to light – it was only recently discovered that 11 million metres of non-compliant low-voltage cable made it onto the UK market in 2010, and only seven million were withdrawn. The low copper content of the cables makes them a significant potential fire risk with little knowledge of where that cable had ended up.

With the sheer scale of construction projects active and planned across the UK, cabling is entwined in home, community and business infrastructures. As such, it’s vital to understand the effect that using a non-compliant cable can have on the long-term safety of a project.

Holes in the Net

It’s not enough to assume it is up to standard just because there hasn’t been a reported problem with that product or supplier before. Good manufacturers conduct extensive tests on the cables before releasing them to market. In addition, third-party accreditation markings provide valuable reassurance by indicating the compliance of a tested length, although just against a sample rather than batch-by-batch or at cable-drum level. There’s also the issue of fraudulent cables available for sale – deliberate sub-standard copies made to look the part. It underlines the importance of testing throughout the cable supply chain, not just at the point of manufacture but also before delivery to the end user.

What’s Should a Site Developer Do?

The worst is to assume. Most projects source their cables from a supplier that can amalgamate different types and sizes into a timely delivered order – going direct is not always an option.

The construction firm and its contractors are relying on the cable supplier to be certain that every batch from every manufacturer is compliant and as expected, which requires extensive testing, most likely beyond the in-house capabilities of most suppliers. The end user should be able to assume that any cable bought from a UK manufacturer, supplier or wholesaler is wholly compliant and fit for purpose, although sadly that’s not universally the case. Admittedly, no control system is ever perfect.

To help, there are a few steps site engineers and developers can take to minimise the risk of substandard or non-compliant cable:

Look into the supplier’s supply chain.

This information shouldn’t be hard to get from the supplier, and it’s basic due diligence for any project. It’s important the supplier is tracking its products and – ideally – testing them with its own or third-party testing facilities. If this information isn’t forthcoming, don’t hesitate to walk away.

Check for the appropriate markings.

Looking at the cable itself is a basic and easy check that is all too often overlooked. It’s not failproof; small changes, a testing mistake, or fraudulent behaviour might see a bad cable stamped with all the right markings, but the print legend is the first indicator of whether the cable is what it should be.

Similarly, does the label have the relevant information including CPR compliance details where appropriate?

Check for accreditations.

High-quality suppliers will proudly display their ISO, BSI and UKAS accreditations. If the supplier offering the best or cheapest deal doesn’t do the same, it’s worth wondering why. In addition to these reputable industry accreditations there are also internationally-recognised marks such as the BSI RoHS Trusted Kitemark which pinpoint organisations that can assure quality and compliance.

If ever a site engineer suspects they might have sub-standard cable on their hands, they can have an accredited third-party test it, or report it to the authorities to do so. An independent assessment into the quality and compliance of the cable will provide certainty, and with a bad batch a remedial action needs to be taken, meaning prevention is always better than cure.

Construction underpins so much of our everyday lives, including our homes, communities, workplaces and transport systems. Cabling might not be the most visible or glossy part, but it’s integral, woven throughout the entire ecosystem, making it crucial to get right.

What’s important to remember is that having an established and successful industry doesn’t automatically mean that its supply chain is always reliable and trustworthy. Instead, it is up to each firm to question suppliers and ensure the industry adheres to its own standards and remains compliant.