Structured wiring is now a well-accepted technology and has been tried and tested in many applications, but not all specifiers have yet embraced the concept. Mark Redfern of Wieland Electric highlights the benefits these ‘plug and play’ systems can deliver to end users and others in the supply chain.

There has been discussion around the need to cut the costs of construction for many years, and certainly some progress has been made, albeit not as rapidly as many people would like. Now, though, the construction industry faces increasing pressure from government to deliver less costly buildings in public sector projects and many private sector companies are also moving in the same direction.

Progress in this respect will undoubtedly be aided by the application of new technologies, such as Building Information Modelling (BIM) which is gaining much attention at the moment. However, it’s important not to lose sight of established technologies that can also contribute to more efficient and cost-effective construction.

Structured wiring with ‘plug and play’ connections is a case in point, as it has been shown to deliver savings of as much as 40% on the final installed costs of lighting and small power. Typically, the time savings themselves will be in the region of 60% but capital costs will be slightly higher.

These figures can vary though. in situations where access is difficult, such as high bay lighting, the savings in installation time can be as high as 70% compared to conventional wiring techniques.

For those readers who aren’t familiar with structured wiring, it uses pre-fabricated and pre-tested plug and socket systems, manufactured off-site so that on-site connection is a simple matter of plugging in the male to the female connector. Some systems also continue to develop to offer greater functionality and ease of use. For example there are now compact ‘micro’ connector systems specifically developed for use with LED lighting in display cabinets. There are also newer 6-pole circular structured wiring systems that use a patented coding system for different applications and use round connectors to minimise space requirements and facilitate installation through firewalls.

As a result structured wiring offers a number of benefits. For example, in addition to the time-savings for the high bay lighting mentioned above, there will be additional benefits in factories, warehouses or retail units where scaffolding or mobile work platforms would disrupt normal business. Anything that minimises such disruption will clearly be welcomed by the end customer.

Highly adaptable

Nor are these benefits confined to high bay lighting. Modern office workplaces tend to be far more dynamic than they were a few years ago because of developments such as hot desking, as well as pressure on organisations to optimise their space usage. The inevitable changes in layout will also require the lighting, and possibly other services such as fan coils, to be reconfigured to maintain the required comfort levels.

With a traditionally wired system this could be very complex and time consuming – so much so that many end users may choose to avoid the ‘hassle’ and leave things as they are. The result is a far from efficient workplace – in terms of both comfort and energy performance. However, with a structured system there is considerably less disruption and less overall cost so the project is more likely to proceed so that the services are optimised to the new configuration of the space.

This approach can also save on wastage because the structured wiring components are re-usable. A few years ago, when a building with structured connections was damaged by a bomb, the insurers insisted that the structured electrical connections were re-used. With conventional conduit and hard wiring, this would all have been thrown away – wasting money as well as increasing the environmental impact of disposing of these materials to landfill. With more pressure coming through European legislation for products to be recycled at the end of their life there is a lot of sense in using a system that offers this versatility.

Structured wiring also offers ongoing benefits when things are likely to change on a regular basis. In a hotel, for instance, the lighting requirements are inclined to change on a regular basis. Using ‘plug and play’ structured wiring introduces a high level of flexibility so that luminaires can be reconfigured as and when required.

Another obvious example is in the retail sector, where changes to display lighting are frequent. With plug and play, this work can often be carried out while the store remains open, as the whole process is clean and efficient with no risk to customers.

This was the case when Wieland Electric’s structured wiring system was installed at a number of Boots stores. The project involved the installation of a three-pole system to enable the installation of accent lighting, combined with a four-pole system that will create an ambient mood with the added benefit of an emergency lighting feed.

Similarly, Tesco was able to use our RST plugs to quickly upgrade refrigeration fan motors at around 50 stores in Ireland, saving on energy and ongoing maintenance costs. A key benefit of this project was that one section of the plug could be fitted to the fan motors prior to arrival at the store, so that on-site time and disruption were reduced. This approach also avoided making alterations to the internal wiring of the cases.

Furthermore, of course, plug and play is ideal in situations where electrical connections are made and un-made on a regular basis. Exhibition stands and hospital beds are both obvious examples of this.

Benefits for contractors

In addition to the time savings that contractors can make on installation, structured wiring also provides an opportunity for them to make optimum use of their multi-skilled operatives. For example, if mechanical operatives are working at high level on pipework, they can also plug in the connections for the lighting. The plugs are configured so there is only one way that they can plug in, so there is no chance of the wrong connections being made. Of course, it is essential that connections at the distribution board and final testing are made by qualified electricians but a simple plug-in operation is well within the scope of any multi-skilled operative.

Plug and play safely

For all of these reasons plug and play wiring has become increasingly popular but it is clearly very important that this technology is used safely and that specifiers are aware of any potential risks.

For example, we have come across situations where male to male connectors are being requested for plug and play ring main circuits. This is potentially dangerous because the convention is that only female connectors should be live – and the good thing about following conventions is that if everyone does it there can’t be any mix-ups and the risk of accidents is reduced.

Also, the female connector tends to have more inherent protection as it is usually shrouded to a greater extent than the male connector. In fact, this is because of the convention, as the expectation is that the female connector will be bearing the mains power and will require enhanced protection against shock – especially when the connectors are designed to allow disconnection under load.

For these reasons we recommend that plug and play systems are only used for radial circuits only, not for ring main circuits.

There is certainly some confusion around this issue and this may have arisen because of the need for such connectors to comply with BS 61535, which states that connectors intended for permanent installation must comply with IP2X when engaged, and the socket (female) part shall also be IP2X when disengaged (IP2X is the ‘standard’ European finger test, which uses a 12mm ball bearing as the ‘finger’ to ensure that even small fingers cannot be inserted into the socket).

Again, the emphasis is on the extra protection for the female connector but many manufacturers play safe by designing their male connectors to comply with IP2X as well. There’s nothing wrong with that, of course, but perhaps some people have got hold of the wrong end of the stick and believe that an IP2X rating for a male connectors means it’s OK for them to be live.

Another point worth mentioning is that, according to EN 61535, these connectors can only be used in readily accessible areas as long as a cap is available, unless they are IP4X rated either engaged or unengaged.

Nevertheless, as I hope this article has made clear, there are many very good reasons for specifying the use of structured wiring, with clear benefits for all parties. Furthermore, these benefits increase as new manifestations of the structured wiring concept come to the market. So it makes sense for specifiers to take a fresh look at structured wiring, if they haven’t already done so, and get up to speed with what is currently available.

It also makes sense to work with a supplier that can meet a wide range of requirements and provide the technical support that may be required through the project.

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