Use of steel wire tray for cable management is growing across a wide range of commercial and industrial applications. EMC goes on-site to examine the installation issues.

During the past few years there has been a marked trend in the electrical contracting industry towards the use of steel wire cable tray for cable management in an expanding range of commercial and industrial applications, from low voltage, mains power and datacomms wiring, up to heavy-duty, armoured and high voltage mains cables.

It is likely that any first-time user with experience in the use of perforated sheet steel tray will be able to install welded steel wire cable management systems successfully in far less time and with less difficulty. Nevertheless, while the two systems provide identical functions, they are radically different in basic design and demand different installation techniques.

As a leading supplier of steel wire tray, Cablofil UK is now providing customers with completely free, practical on-site training in the use and installation of this cable management system. Service corridors and voids are becoming increasingly congested as more and more m&e systems and services are incorporated in modern buildings. On-site training can demonstrate readily the speed and ease by which the steel wire cable tray system can overcome practical problems encountered in installations, such as accommodating the bending radii of cables or ‘setting' up or down around other services or obstructions.

Involving a group of around ten people, a typical training session would be completed in about 30 minutes. The training engineer will be equipped with a few short lengths of steel wire cable tray, together with a range of accessories such as couplers, channel clips and other potentially time-saving components. Having first established if any of those present have previous installation experience with wire tray, it will be stressed that the primary objective is to enable the product to be installed quickly, easily and safely, demonstrating how bends, tees and other necessary accessories can be formed as required.

The initial part of the session is used to show the comparative speed with which two lengths of cable tray can be joined together using a fast coupler. Most installers would be used to joining successive lengths of traditional perforated sheet steel tray in a couple of minutes or so. Two similar lengths of welded tray can be securely joined in no more than 20 seconds and each member of the group is encouraged to practise applying the couplers and removing them safely.

The training engineer will then proceed to cutting and forming the cable tray using the bolt-cutters supplied by Cablofil. These are both specific to the task and integral to operator health and safety. The croppers are capable of cutting the maximum steel wire gauge of 6 mm. The jaws are designed to give an offset cutting action across the welded intersections on the tray, reducing spurs and sharp edges. Demonstrating how the tray can be cut correctly, it is placed with the base uppermost.

For the first cut, the bolt-cutters are placed with the jaws held firmly against the longitudinal wire. The natural loft of the jaw provides the correct cutting angle while the ‘beam' wires that cross the tray are used as a guide. The top ‘safety' wire can be cut safely by aligning and angling the bolt-cutters. Again, the participants are each given the opportunity to carry out the cutting operations, moving on subsequently to follow the training engineer's example in forming ‘accessories' including gusset flat bends, internal bends and angled bends.

With the principal training tasks completed, the Cablofil trainer will examine the planned installation, confirming that all available options have been considered in terms of fixing brackets, loading capacities and spacings. While the basic lengths of tray, couplers and assembly kits may have been placed on order, it is common for the installer to have overlooked the need for supports or suspension brackets and fixings. Because training is arranged to take place before any final deliveries are made, the timing of the training session enables any ordering oversights to be rectified and the products delivered without delaying the installation programme or incurring additional cost penalties.

While steel wire cable tray itself provides an exceedingly cost-effective alternative to traditional perforated sheet steel products, on-site training can provide even further advantages. Reduced installation times, improved installation quality and possible reductions in accident-rate impact on the contractor's bottom line and provide better customer satisfaction. These factors can also give a vital competitive edge, ensuring continued financial health in an increasingly tough commercial environment.

Saving time – and money

For most industrial and commercial electrical installation projects, the key to successfully tendering for the work and ensuring its profitable completion will be the contractor’s ability to estimate total costs accurately at an early stage. While the initial outlay in terms of plant and materials is clearly an important element in the final price, typically these costs will be outweighed by labour costs.

The high strength and ease of handling of steel wire cable tray are important, but the savings in installation time offered provides one of its most significant advantages. The simple use of bolt-cutters to cut straight sections of tray allows this to be done in around half the time needed for perforated sheet steel. Attaching fast couplers can take as little as ten seconds, enabling completed sections to be joined and installed in a maximum of six minutes – a 30% time-saving. The savings in total installation time offered by steel wire tray over the sheet steel equivalent for all standard thicknesses from 50-600 mm, are listed in Luckins’ ‘Green Book’ – Electrical and Mechanical Installations Times Guides.

As well as eliminating the need to stock the full range of bends, tee-pieces and risers required for a sheet steel tray installation, similar components for welded wire tray can be simply and very rapidly fabricated on site, providing further time savings. Typical listings in the Green Book show very significant reductions, particularly when installing heavy-duty products in tray sizes up to 600 mm. These can range from six minutes for each crossover on 50 mm tray, up to 20 minutes for 600 mm products.

The ability to slash labour costs by 30% without compromising installation quality, the health and safety of the workforce or the number of employees, represents a compelling case for adopting the steel wire option.

Down Cisco way

Based at a site in Reading, Berkshire, Cisco Systems’ new data centre represents the very latest in leading edge IT installations. Cisco is a worldwide leader in networking for the Internet and the development of Internet Protocol (IP)-based networking technologies.

The new data centre employs extensive, high-density wiring and cabling for all mains power distribution and low voltage networks including fire, security and surveillance systems as well as the entire fibre optic and other datacomms cabling networks. Containment and protection for all cabling and wiring is provided by more than 1000 metres of Cablofil welded steel wire cable tray, installed by main m&e contractor Skanska UK.

With its electrical installation team fully trained in the use of the wire tray cable management system under Cablofil’s on-site training scheme, Skanska was able to complete the complex wiring and cabling installation on time and within budget, with zero time lost through accidents. John Webb, a member of the company’s electrical installation team commented: “The training session we had from Cablofil was completely hands-on, giving us all the chance to practise cutting and forming using the techniques we were shown. There’s absolutely no doubt in my mind that wire tray is the way to go.”

The implications of expert product training for employee health and safety were a further consideration for Skanska, as the company is currently operating a “Safety @ Skanska” programme in partnership with Mencap, aimed at improving safety company-wide. Skanska UK has agreed to donate £1 for every near miss or hazard formally reported on any of its workplaces, with a further donation of £500 at the year-end for every accident eliminated when compared to the 2004 performance.

Source

Electrical and Mechanical Contractor