Enclosures are an important part of network infrastructure, protecting a wide variety of electrical equipment.  However, the materials and properties of enclosures can sometimes be misunderstood.  In addition, there has been a growing trend for Glass Reinforced Polyester (GRP) enclosures due to the material’s supreme durability.  But there are some situations where this solution isn’t necessary or appropriate.  Here Chris Edwards, product manager at HellermannTyton, offers advice on how to choose the right enclosure.

Enclosures are important for the protection of valuable electrical components as well as safeguarding personnel.  Choosing the right enclosure is as important as selecting the electrical equipment itself.  It is always advisable to choose a high quality product, rather than trying to save a few pounds by purchasing a substandard one and in recent years the rise in popularity of GRP enclosures has been as a result of contractors recognising the importance of durable solutions to avoid leaks, damage to equipment and risks to public safety. 

However, while GRP is a hard-wearing option, it is still important to consider the right material and properties of the enclosure in relation to the application, particularly as GRP solutions tend to be 20 to 30 per cent more expensive.  With a wide range of enclosures available in varying materials, it is important to recognise that each type has their strengths and weaknesses in different situations.  By understanding the advantages and disadvantages of each individual product, contractors can ensure the right enclosure is used.  After all, buying a high quality enclosure, but in the wrong material, can be a costly mistake and one that could be easily avoided.

There are three common materials that enclosures are manufactured from – mild steel, stainless steel and GRP.  Looking first at mild steel enclosures, these are most suitable for general purposes.  It is a cost effective option for indoors applications in both industrial and commercial premises, and its ability to be easily modified has added to its popularity; however it would appear that contractors are recognising its weaknesses.  Mild steel can corrode quickly, meaning it is unsuitable for any external applications.  Due to its poor anticorrosion properties it has to be treated and this can be an expensive exercise, meaning it is not the cost effective solution it appears to be.

Turning to stainless steel, this has been a popular material for enclosures for many years.  Typical applications include food manufacturing and processing, as well as the pharmaceutical industry.  Stainless steel enclosures also provide a suitable solution for external applications as it can withstanding much more aggressive environments than mild steel.  In addition, it is rust resistant – although it should be noted that depending on the grade and the environment conditions, tarnishing and corrosion can sometimes occur.  An added benefit is that stainless steel has its own natural finish, so it does not require any additional treatment before being exposed to the elements.

GRP enclosures have been specifically designed to cope with harsh environments and been popular, standard products in Europe for many years.  It is particularly suited to outdoor applications as it does not corrode in damp or wet conditions, even when exposed to sea salt.  The material also offers excellent protection against UV rays, so it won’t discolour or weaken in outdoor settings.  Due to its strength, corrosion resisting properties, and the fact it is an insulated material, reinforced polyester is becoming a major competitor to steel enclosures.

As well as all the many properties of the material, reinforced polyester is self-extinguishing, which significantly reduces the risk of fire.  Some reinforced polyester enclosures also offer the benefit of being halogen free.  These features combined make them ideal for enclosed spaces where public safety is paramount, such as airports, rail applications and underground installations.  This makes the list of suitable applications for reinforced polyester enclosures quite extensive.  However it is not entirely impervious and for example, over time machine tool oils can affect its integrity.  Solvents and abrasives should also be avoided, deep scratches need to be filled in and if any work is carried out on the enclosure, cut or exposed surfaces, holes and edges must be treated to avoid moisture ingress.

So you can see that it is simply not the case of one enclosure being the ideal solution for any application.  But with plenty of choice available, contractors can be sure they can source the optimum enclosure even to fit in the most awkward site or to house the required equipment with maximum economy of space, avoiding the expense of an unnecessarily large enclosure.