When selecting a distribution switchboard, many specifiers and designers opt for a fully engineered custom built solution. However, Eaton’s Colin McAhren claims that, for some applications, there is a more cost effective approach.
There are a number of different types of distribution switchboards that are currently available, and a complicated board could well be the right solution for your application. However, many projects are much less complicated. All they need is an incomer and a few outgoing ways, possibly with some metering provided to help the end user to meet requirements of Part L of the Building Regulations.
For applications like this, there’s a much simpler solution available based on the humble enclosed fuse switch disconnector. It’s easy to think of these convenient and cost effective units as stand alone devices that can only be used to provide power to individual loads, but to do so is to greatly underestimate their versatility. The reason is that the best ranges of fuse switch disconnectors now feature compatible busbar chambers.
Simplicity
Therefore, it is readily possible to build a distribution switchboard that comprises an enclosed fuse switch disconnector as the incomer and a series of similar but smaller units to serve as the outgoing ways, with everything linked together by a busbar chamber. In principle, that’s all there is to it – a cost effective, almost instant distribution switchboard. It’s also modular, so future modifications are easy to incorporate.
Of course, as always, the devil is in the detail and it’s not every range of enclosed fuse switch disconnectors that is going to be suitable for this type of application. The first thing to check is that busbar chambers are, indeed, included in the range and, if they are, that they have been tested in line with BS EN 60439-1, and that they have an adequate conditional short circuit current rating for the application in hand. It is worth noting, in this respect, that types with 63kA rating at 550V are readily available.
The next step is to make sure that the range includes fuse-switch disconnectors with ratings that cover the needs of the application. Leading manufacturers offer units with ratings as high as 800A, which will typically be used as the incomer, with a selection of smaller units down to 63A for the outgoing ways. Some ranges also include fully compatible unfused switch disconnectors, which can be useful in certain applications.
Requirements
Not long ago, that would probably have been all that was needed in the way of basic components. However, there is now the need to account for energy usage by type of load, as dictated by Part L2 of the Building Regulations. As a result, sub-metering is a necessity for almost every distribution system. Therefore, it is worth seeking out a fuse switch disconnector product range that includes convenient sub-metering packs that are uniform in appearance with the switches, and that are easy to install with them.
It is perfectly acceptable to mount this type of distribution system on a convenient wall. However, quite often a convenient wall isn’t available. To cater for these situations, the most comprehensive fuse switch disconnector product ranges include pedestal sets that enable free-standing, floor mounting assemblies to be readily constructed. Some pedestal sets even include floor mounting bolts as an aid to speedy and convenient fitting.
If the product range under construction includes all of the items and features mentioned it will almost certainly provide a satisfactory basis for a small distribution. However, that’s not quite the end of the story, as there are many other product related features that separate the merely satisfactory from the best. One of these is quality of construction. The best products have enclosures fabricated from heavy gauge rust protected sheet steel, with a tough paint finish to ensure long life even in demanding environments.
Then there are the features that make the difference between an assembly that’s easy to install and maintain, and one that’s a headache. These include the availability of accessories to simplify installation, such as cable extension boxes and spreader boxes, along with design features such as the provision of adequate space within the enclosures to allow for fast and convenient cabling.
Summary
The features discussed are embodied in the Glasgow product range from Eaton’s Electrical Sector. In addition, the range also incorporates Exel 2 switch disconnectors and switch disconnector fuses to offer greater flexibility.
When it comes to power distribution systems, there is often a very convenient, very versatile and very cost effective alternative to the usual custom built solutions. Just think fuse switch disconnector, but do be sure that you choose products from a range that’s comprehensive enough to cover all your requirements and that offers proven performance and quality.
