Kassel Rural District: Broadband expansion in Rittal outdoor enclosures

Outdoor Enclosure

High speeds are the order of the day on Germany’s information highways – especially after a network expansion. The German Federal Association of Broadband Communication estimates that households in Germany will be surfing the net at average transfer speeds of 200 Mb per second by 2020 at the latest. In rural areas in particular, large sums are currently being invested. In 2012, the rural district of Kassel connected 74 areas in 23 municipalities to the DSL network.

“We took delivery of enclosures that had been prepared precisely to our requirements”
Klaus Peter von Friedeburg, Managing Director of ACO Computerservice GmbH, Kassel

Rittal supplied more than 150 outdoor enclosures that had been specially customised for their intended use. The technology inside links the signals arriving by glass fibre cable or microwave radio relay to Deutsche Telekom’s existing copper lines.

Coping with heat

To stop the multifunctional enclosures from overheating, Rittal chose an entirely double-walled construction and incorporated vent slots close to the ground and under the enclosure roof. When the outer skin heats up, the air in the cavity between the two aluminium sheets also gets warmer, which causes it to rise up, creating a vacuum effect and drawing in cool air from close to the ground. This thermal flow provides extremely effective cooling in a natural – and completely free – process.

Extending service life

Keeping temperatures under control helps to extend the service life of the electronics and, more importantly, safeguards availability. That is particularly important when the outdoor enclosures are located along radio relay lines in the middle of the forest and are therefore very difficult to reach. However, the stringent requirements for failsafe operation are not restricted to simply withstanding extreme temperatures. When positioned close to roads, the compact units can be exposed to very different immediate and long-term hazards. For example, Rittal uses a special coating made from pure polyester to protect the units from salt spray during winter.

Protection from traffic accidents and vandalism

Taking into account the risk of traffic accidents, Rittal designed the total of 150 enclosures installed in Kassel so that they can be repaired or the outer enclosure even completely replaced without having to switch off the communications technology inside. “When an excavator bent a door completely out of shape while it was being installed, we were able to see for ourselves how quickly and easily repairs could be carried out. A replacement was available immediately and Rittal’s service team arrived at the scene promptly,” says ACO Key Account Manager Stefan Finger. The enclosures have also been built to meet resistance class 2 and therefore offer adequate protection against vandalism.