When it comes to cable management, debates over the suitability of one solution over another are commonplace, but when it comes to the pros and cons of perforated cable tray in relation to wire mesh things can become heated. In order to get a balanced view on the subject Electrical Review spoke to Nigel Leaver, a marketing manager in Legrand’s cable management division, which manufactures and sells both products

Tracking the perforated tray versus wire mesh debate back to its origin is relatively straight forward, with it all beginning when wire mesh first squared up to perforated tray with a view to grabbing market share and establishing itself as the solution of choice.
Ever since, this battle between the new kid on the block and the traditional old master has demanded industry attention, with the two trading blows, but neither being able to deliver the telling, knock-out punch.

As a manufacturer of both types of tray we are ideally placed to referee such a bout – providing as we do a balanced and non-biased opinion on both solutions. Unfortunately, this neutral position doesn’t mean we can resolve the debate as perforated and wire mesh tray are both perfectly acceptable solutions and both are covered by the same European standard for tray and ladder (IEC 61537).

Instead, the decision of when to use one rather than the other is very much dependent on the installation – meaning the question to ask is not, which is the best, but rather, how do I choose between them?

Round 1
One of the main benefits of wire mesh tray is that it’s said to be cheaper and quicker to install, and in many situations this is the case.

Take for example an installation in a confined space with numerous twists, turns and obstacles to cope with. In this situation wire mesh tray is cheaper and quicker to install due to the fact it is designed specifically to be configured on site without the need for factory manufactured fittings. However, this task does need to be undertaken by experienced installers so as to avoid potential problems such as sharp edges caused by poorly cut and installed fittings.

Of course, installations do vary and if we were faced with one that required numerous straight lengths then we would typically advise in favour of perforated tray. The reason being it’s generally stronger and so only needs supports every 2.0 to 2.5 metres, rather than the 1.0 to 1.5 metre intervals that wire mesh requires. Therefore, with fewer cantilever arms or trapeze hangers to fit, the installation time, and subsequently cost, is significantly reduced.

Round 2
Another differentiating factor between the two that is often picked up on is that wire mesh tray is generally installed using accessories that are made on-site, whereas perforated uses dedicated factory fittings.

Again, the debate focuses on ease of installation, and again no definitive answer can be given. As perforated tray comes with factory fittings, some may say the job of installation is far easier than it is when having to create fittings for wire mesh on-site.

On the other side of the argument, the flexibility provided by being able to create fittings on site can be invaluable – especially when you consider just how quickly these bends and fittings can now be made, and the speed with which they can be secured using clips like our Fastlok. And of course, some manufacturers do now supply factory made bends, tees and risers for wire mesh tray with the aim of tipping the balance in its favour.

Round 3
The suitability of the two types of tray in relation to different cables also needs to be considered. Both can carry power and data cabling, however, when installing power cables these need to be fitted with steel wire armour or a second sheath of PVC-U as perforated and wire mesh tray provide cable support, rather than full mechanical protection.

Following directly on from this, is the question of how cables are secured. In the majority of instances this can be achieved through the use of cable ties, but this approach becomes unsuitable when larger cables, such as 3-phase power cables, need to be carried. Then there is no choice but to secure the cables with specially manufactured cleats, which need to be fixed securely to an already rigid system.

Until very recently this was something that could only be achieved to a satisfactory level using perforated tray, but a UK cleat manufacturer has recently developed, tested and launched a wire mesh clip that provides a strong and reliable means of securing cables with high fault levels, which can be used in conjunction with heavy duty trefoil cleats – a development that allows wire mesh to compete with the traditionally stronger perforated tray on this kind of installation.

Round 4
Finally, the availability of different finishes should also be taken into account. Wire mesh is most commonly supplied with an electro-plated finish, which is similar to the standard pre-galvanised finish of perforated tray. Both systems can also be supplied in stainless steel or hot dipped galvanised finishes for more aggressive environments. In fact, it’s only when a system is installed in an area where corrosion will be very high, that a difference between the types of finish becomes significant. In these scenarios, perforated tray can be given a thicker galvanised coating (deep galvanised) that uses special sheet steels that can provide a galvanised thickness of at least three times that normally used – a solution that gives an extended product life three times that of a standard hot dipped galvanised product and up to six times that of electro-plated wire mesh cable tray. All of which means, the more aggressive the installation environment, the more suitable perforated tray is.

Round 5
In terms of general usage, the rule of thumb tends to be that wire mesh tray is used in applications where the installation is in a false ceiling or cavity floor. One reason for this is that its design allows for better air circulation, thus reducing numerous potential problems caused by overheating cables. Meanwhile, in installations, which are accessible to the general public, and therefore at risk of vandalism or accidental damage, perforated tray provides greater physical protection to the cables due to the fact it’s secured with screws, which are harder to vandalise and less likely to be accidentally dislodged than the quick-fit tabs used to secure lengths of wire mesh tray.

The big fight verdict
As you can see, not only is it hard to say which of the two solutions is better, it is also difficult to provide a definitive guide as to when to opt for one over the other – and, with the strides being made in the development of wire mesh this boundary is likely to become ever more blurred. Therefore, in order to ensure that you get the best possible solution for any given installation, make sure you talk to a company that isn’t biased.