Can GRP enclosures reduce costs for trackside applications?

摘要

As part of a cost reduction programme to reduce overall spend by 20%, Network Rail has begun to switch to 2-core cables that are cheaper to purchase which reduces installation costs. However, since there is no earth core, this requires Class II installation, which means traditional metal enclosures may not be the best solution. This is why many suppliers, such as MGB Engineering, are moving to GRP enclosures for their latest products. Conventional single-phase, low voltage installations use 3-core cables where the size of the individual cores is governed by the design current and the total cable length, neither of which will change in the event of a replacement cable being required. The advantage of 3-core cable is that the inclusion of an earth core keeps the application safe, without requiring any additional insulation. Network Rail is looking for solutions which can help it achieve the required savings. It has gone to the lengths of designing a 2-core cable, which is cheaper than traditional 3-core; this must now be specified for all trackside installations. However, in order to maintain electrical installation regulations, Class II protection criteria must be met. MGB Engineering Ltd., a leading manufacturer of safety critical rail products, has recently launched a new FSP switch gear enclosure, a component of the Functional Supply Point (FSP), which takes advantage of GRP enclosures to provide Class II insulation. Mike James, engineering director, explains how they worked with its supplier, Spelsberg UK, to design an efficient and reliable solution, "We had previously worked with Spelsberg on another project, so we were aware of the company's technical knowledge and design capabilities. When we began to think about the new FSP switch gear, we approached Spelsberg and discovered that it had a product on the shelf which could be developed to produce a Class II power feed."