Electrical systems that could almost be designed for churn
Pre-fabrication and the use of modular systems assembled off-site is now common practice throughout the construction industry. MIKE JOHNSON discusses the benefits of modular wiring systems.In a fast-track, high-performance construction market, there is continual pressure on installers to deliver the required solution with less site time, higher integrity and a lower total cost of installation. As a result, there is also pressure on specifiers for a design that will facilitate such a fast-track approach while providing the end user with a flexible solution that will meet changing needs in the future. So it is hardly surprising that non-traditional methods that would have been rejected just a decade ago have become accepted in many construction disciplines. A case in point is pre-fabricated building services, covering everything from boiler rooms and switch rooms delivered on the back of a lorry and simply craned into position — right through to the wiring of the power, lighting and data systems. Building-services contractors that see beyond the cost of the materials to the overall cost of the installation have embraced these concepts and use them to increase productivity and profitability. The end client also gets a more cost-effective solution delivered in less time, so pre-fabrication is the obvious win-win solution for many projects. One of the most striking successes of pre-fabrication is the introduction of modular wiring, first in the USA, and now standard wiring practice there. It is now being applied worldwide. Modular wiring comprises cable assemblies and enclosures manufactured off site so that on-site connection work simply involves connecting the various components to complete the power, lighting or data installation. In some projects, modular wiring components are integrated into equipment such as luminaires and fan-coil units before delivery to site, speeding up the whole process even more. Flexibility
These time savings can be significant — often as much as 80% compared to conventional installation methods. Even with slightly higher capital costs, overall savings can be up to 50%. A modular design also offers a high level of flexibility. When site requirements dictate a variation from the original design, re-configuring the wiring is very simple. From the end user’s viewpoint, that flexibility extends to later re-configuration of lighting, data or power as the needs of the building change. All these services can be altered with the minimum of time and disruption to staff, a factor which has become an important economic consideration to fast-moving business where change is almost constant. Modular wiring is now widely accepted in commercial, residential, health and education sectors. It is widely predicted that modular wiring will become standard wiring practice in the UK within the next 10 years. Contractors can also make better use of their workforce, tying in with the increased use of multi-skilled operatives by many companies. Using a fully qualified electrician to make final connections to the distribution board is compulsory, of course. But in other areas, where work simply involves plugging in connectors that are designed so they can only be connected correctly, there is much more scope to use other operatives. An obvious example is where a non-electrical trade is working at a high level, when it makes perfect sense for them to plug in a few connectors as well. In addition, system integrity and safety is higher because all components are factory tested in a quality-controlled environment. This has a direct effect on commissioning times and the incidence of call-backs. Two types of modular wiring system are widely used in the UK. The non-armoured LS0H (low-smoke zero-halogen) system is primarily used in false ceilings where less mechanical protection is required. The armoured system is used in false ceilings and raised floors where enhanced mechanical protection is generally needed. 3, 4, 5 and 6-pole systems are available to satisfy the requirements of most power- and lighting-distribution applications. A combination of 1.5, 2.5 and 4.0 mm2 single- and multi-core LS0H cables are used for both non-armoured and armoured systems. In choosing the most appropriate modular wiring system, it is important to consider a number of factors. First, the system must comply with all relevant standards and regulations, and there are a number of key elements that ensure compliance. It is essential that the modular wiring system has a mechanically coded, unique connector system that cannot be linked to others forming part of the same electrical installation. Safety
The female, live connection must be fully shrouded to ensure electrical safety. Connectors must be fully colour coded for ease of identification and to help prevent components being interchanged between different, incompatible systems. Connectors must be suitable for both power and lighting. When all these factors are taken into consideration, it is clear that the benefits of modular wiring are easily quantifiable both in theory and practice, with numerous examples of smaller and high-profile large applications now a matter of record. The major barriers to their universal acceptance have been tradition and conservatism, but time and experience have worn these down, and modular wiring will soon be the norm rather than the exception. Acceptance is gaining pace, and manufacturers of these systems must invest heavily to meet increasing demand. Apex has responded with a multi-million pound investment in dedicated purpose-built manufacturing facilities in County Durham, the first of its kind in the UK and incorporating a high degree of semi-automation and specialist plant and machinery. Coupled with a strong commitment to stocking component parts, this has enabled the company to offer the best availability and assured quality of complete manufactured systems. Mike Johnson is sales and marketing director with Apex Wiring Solutions, St John’s Road, Meadowfield Industrial Estate, Durham DH7 8RJ.