Placing automation and IT equipment - such as servers, UPS batteries, PLCs, and inverter drives - outdoors isn’t ideal. It exposes sensitive equipment to moisture and dust, weather events, shocks and vibration, and damage from vandals. But sometimes, it is simply unavoidable, for example in the case of railways (HS2), mobile phone masts, or electric vehicle charging stations.
Very often, its only real protection is the enclosure that it’s housed in. It’s therefore important that the enclosure you select suits the application, its location, and supports other issues such as ease of user access (possibly including its electromagnetic capability, or EMC).
The starting point when specifying most outdoor metal enclosures is whether to choose one that is single- or double-skinned.
Single-skinned enclosures typically have a simpler construction (often a single sheet of folded steel) and are usually cheaper. They are suited to installations requiring a simple internal configuration with fixings such as mounting plates and 19” angles, as well as private locations away from public access (including rights of way) and for housing equipment that isn’t particularly temperature sensitive.
As all this implies, single-skinned enclosures are not good at regulating their internal temperatures – which can rise considerably with UV solar gain - nor are they especially robust.
Double-skinned enclosures are typically a better option for equipment requiring an optimum temperature range. They are also more suitable for systems placed in public spaces where these systems may need extra security protection. And they are usually quicker and easier to repair/maintain.
If we look at each of these three considerations in turn:
1. Optimum Temperatures
Temperature regulation is a major concern for many outdoor applications because electrical systems and electronic components can be very sensitive to temperature fluctuations.
Not only does electrical equipment generate heat through its operations, there is also heat that collects inside the enclosure through UV solar gain. So, if you have an enclosure that is sealed tightly enough to keep dirt and moisture out then inevitably the temperatures inside will rise; the only way to remove it is to add either passive and/or active cooling solutions.
That said, a double-skinned enclosure does offer some temperature regulation advantages over single-skinned alternatives. Its outer skin reflects some of the heat away, while the void between the two skins also helps to funnel excess heat up and through a vented roof (the chimney effect).
This doesn’t necessarily mean you won’t also need to add-on climate management equipment, but it can reduce the amount of cooling that’s needed, which in turn will help lower your energy costs.
2. Enclosure Security & Resistance Class
Some enclosures have design features that make them more difficult for potential thieves to gain access, while a few more also have a Resistance Class (RC) rating. This rating recognises an enclosure’s ability to withstand a forced entry attempt.
(A selection of Rittal’s enclosures have RC 2 ratings, to help protect against vandalism and theft).
3. Quick Repair/Maintenance
Double-skinned enclosures are usually constructed out of panels which are securely fixed to an internal frame. Should a panel be damaged then a new one can be ordered, delivered to site, and fitted in-situ.
Single-skinned enclosures, on the other hand, are more vulnerable to damage and if they are damaged, they are likely to be difficult to repair. In that instance, your only option is to transfer all the equipment to a new enclosure which can create significant downtime for systems supporting critical infrastructure (such as signalling on the railways).
Conclusion
When it comes to protecting outdoor electrical and electronic equipment, it’s worth considering whether a double- or single-skinned enclosure better serves your particular circumstances.
Each one has its place, but a double-skinned unit provides an extra layer of security and peace of mind for very vulnerable applications.
Additionally, consider the implications of which material you need, as this decision often goes overlooked. Every solution with Rittal is tailored to your specific situation, so discuss your next project with us today!
If you're still unsure which choice is the best for you, read our eBook, 'Mastering Outdoor Installations: The Ultimate Guide to Selecting the Right Enclosure'.
