How to Protect a Telecom Outside Plant Cabinet from Thermal Damage

 

All forms of electrical equipment are susceptible to failure if they get too hot, and telecom equipment, even though it is built to high standards, is no exception. Usually the failures can be traced to an inadequate assessment of the total heat load in the cabinet, leading to higher than expected temperatures, or as a result of failure of the enclosure cooling system. Here are some ways to protect a telecom outside plant cabinet from thermal damage.

What Causes Thermal Damage?

Most telecom equipment is designed around powerful electronic components. Although such electronics can be designed for very high temperature operation, such as under the hood of a car, most commercial telecom equipment is not built to such rigorous standards. Consequently, telecom equipment malfunctions if it gets too hot and eventually fails.

In addition, it has been demonstrated that running electronic equipment above its recommended operating temperature decreases its service life. It is generally accepted that for every 18 °F temperature rise, the service life is halved.

Enclosure Design and Placement of Equipment

During cabinet design, careful consideration should be given to airflow inside the cabinet and to the placement of equipment to ensure that hot air from one piece of equipment does not enter equipment above and cause localized overheating. This is an important consideration because telecom cabinets are often quite cramped. As a general rule, equipment that generates less heat should be below equipment that generates a lot of heat.

Thorough Assessment of Ambient Conditions

Great care should be taken to assess the worst-case ambient conditions at the location of the cabinet. Climate data should be obtained to establish the maximum ambient temperature expected, and due consideration given to the effects of solar radiation. The enclosure’s internal heat load should be carefully calculated, and factors such as cabinet finish and insulation assessed to ensure that the total heat load calculations are valid.

Selection of an Appropriately Sized Cooling Solution

Cooling solutions vary from natural ventilation to the use of filtered fans and closed loop cooling solutions such as air conditioning and air to air heat exchangers. Each has its advantages and disadvantages, but the most important criterion is that the heat generated inside the enclosure is removed and an internal temperature that is below the temperature rating of the equipment is maintained. In all cases, the enclosure temperature must not be allowed to exceed 104 °F, but there are many factors that suggest that the optimum cabinet temperature should be much lower than this.

If an air conditioner is used, it is recommended that its cooling capacity should be closely matched to the heat load with only a small reserve capacity. The reason for this is an oversized air conditioner will cycle frequently, causing fluctuations in temperature. Additionally, humidity control will be poor and the air conditioner compressor could fail due to excessive cycling.

Remote Cabinet Monitoring

It is very important that some form of remote monitoring is used to ensure the wellbeing of the telecom cabinet. This will provide early warning of impending problems and notify the maintenance team in case of a cooler or power failure. Various solutions are available, but whatever is chosen, it’s important that the cabinet temperature is monitored, as ultimately this will prevent thermal damage.

Regular Maintenance Inspections

Regular maintenance inspections should be conducted with a frequency that depends upon the ambient conditions. If external filters are used, they need to be inspected, cleaned and changed at certain intervals to ensure they are in good condition. Although remote monitoring is effective, it cannot replace regular physical inspections that will reveal looming problems such as faulty door seals, loose connections and excessive vibration.

Select Equipment from Top-Class Suppliers

It is essential designers source their equipment from telecom cooling equipment suppliers who manufacture robust and reliable equipment. Thermal Edge enclosure coolers are UL listed and carry NEMA ratings, and are designed to survive the toughest outside plant conditions. Thermal Edge has a reputation for no-nonsense designs that are durable and its equipment enclosure housings are tough and supplied in powder coated or stainless steel finishes. Avoid thermal damage to your outside plant cabinets: speak to our Sales Team and let them demonstrate the Thermal Edge difference.