Cable management: Going public with electrical installation
Tight lead times from clients throughout the construction sector are leading electrical installers to look at ways to shave valuable time off all projects. A main driver for the cabling industry to introduce innovation to save time on projects will come from work won in the public sector, on schemes including schools and hospitals.
Projects such as the Government’s Building Schools for the Future programme will provide cabling installers with a fair chunk of work over the next few years. In his pre-budget speech, Gordon Brown backed the Building Schools programme further, with an extra £36bn for construction and refurbishment.
For any contract, time is money, and the public sector can be very cost-efficient, so any savings are absolutely critical. Lead times on schools projects are dictated by term times, so everything is tight.
It is a sign of the electronic age that there is more data and information cabling going into school buildings now than there is power cabling. When working on schools projects, installers are faced with increasing pressure to fit more cabling in less space. The same heavy demands to install more data cables into smaller spaces are true across the board, from other public sector projects such as hospitals to private sector projects like offices and shopping centres.
With these high demands in mind; if contractors went into a job with a clean sheet, time, space and cost would convince them to specify wire cable trays over alternatives such as perforated steel.
As far as installation time goes, it is generally considered that you can install three metres of traditional perforated steel tray in an hour. Using wire cable tray allows you to install cabling 30% faster, and we have installers who say they can install up to 50% extra an hour.
The time savings come mostly because wire cable tray is lighter and easier to handle than perforated steel. If you save half an hour each time you transport 20 or 30 metres of wire cable tray across the site, that saving will make a big difference by the end of the project.
The biggest time saving comes with the product’s flexibility. Contractors buy wire cable trays in straight lengths, cut sections out with bolt cutters on site and bend them to fit. If you need a 27 degree bend, for example, you cut a section out of the side of the tray and bend it to suit. When working with bends and junctions for perforated steel trays, installers would have to order pre-manufactured components ahead of time instead of using bolt cutters on site. Using wire cable tray, installers can modify the awkward sections while the rest of the team puts in the straight sections.
You do not need power tools or a licence for hot work when working with wire cable tray as you would when working with perforated steel tray. This is a great benefit as if you were working in a hospital, for example, you would have to close off the ward.
The flexibility of wire cable tray allows installers valuable inches with which to work in tight, refurbishment projects. We are currently supplying a project for Marks & Spencer, where the services are so tight almost to the point that the contractors working on the scheme have difficulty getting their fingers into the space. With wire cable tray, they have a flexible tray that they can modify to fit the space available.
Installing wire cable trays is not rocket science, and the job can be carried out by an experienced cabler under supervision by an electrician. This leaves more qualified and experienced operatives free to use their skills elsewhere on the site. We offer free on site training to installers, and a typical training session will take approximately 30 minutes. Our engineer will show installers how to join lengths of tray, and how to cut and form it using bolt cutters. Installers will also be tutored on how to fix brackets, loading capacities and spacings, according to the needs of the site.
Many contractors working on public sector projects, such as hospitals, do not have English as a first language. Technical terms do not translate well, and it helps if installers are working with something that is straight forward to use. The beauty of wire cable tray is it is a very visual product to work with, which is very convenient when it comes to teaching installers to use. We have found that trainers can just hand it over to people and they can understand easily what is required to install it.
Because wire cable tray is easy to handle, it also makes things easy for installers to observe health and safety regulations. In these safety-conscious days, most people on site will be wearing gloves. This can be incredibly laborious, and you need a product that you can feel and work with through the gloves.
Because wire cable tray is easy to work with, it is also suited to factory conditions, which can address on site restrictions of time, space and costs. On our biggest project, Heathrow Terminal 5, space and time were particularly tight, and contractors such as Amec, Crown House and Balfour Kilpatrick used offsite methods of construction. This relieved the logistical headache of transporting millions of components to the site. Approximately 70% of the wire cable tray we supplied to the T5 project was used in offsite fabrication. As wire cable tray uses fewer parts than perforated steel, the T5 project saved 2.5 million to 3 million components, which was a huge cost saving across the project.
When using offsite modular components, contractors incur costs on site like cranes, but it is still a very viable option, as it can reduce labour costs. Following the decision by the former Office of the Deputy Prime Minister to recommend that the construction industry should explore Modern Methods of Construction, we can expect to see a lot more work coming offsite in the future.
Despite higher specifications for buildings to include more cabling, and greater demands that contractors install cabling on time and in more constricted spaces, installation costs have not risen very much over the last ten years. This can be put down to demands from clients for contractors to find more efficient and economical ways of getting the job done.
The public sector holds great potential for the cabling industry, and it is up to the sector to find innovative means to meet this demand within its very cost-efficient specifications. One way of doing this is by studying the efficiencies of cabling products.
Wire cable trays are 30% quicker to install than perforated steel, and the materials are 25% cheaper. Considering that a hospital can take 500,000 metres of cabling, which, in turn, would use 40,000 metres of wire cable tray; this can make an enormous saving just on one job.