Electronic Products & Technology

Addressing circuit protection for data centre racks

By Carling Technologies Inc.   

Circuit Protection Electronics Chassis circuit breakers circuit protection data data centres OEMs PDUs racks telecom

Tending to the requirements and power distribution of data centre racks

Data centres are quickly evolving thanks to initiatives driving the adoption of green technologies, reduced physical footprints, increased densities, and better environmental controls. In response, several OEMs now preconfigure equipment racks with computing and storage solutions, helping to increase efficiencies while incorporating management controls, monitoring systems, and expansion capabilities.

Integrated, well-designed equipment racks are now the foundation of a data centre. However, racks can (and do) fail, bringing operations to a halt and introducing downtime into operations that are expected to function 24/7. Because of the equipment rack’s importance in a data centre, it is crucial for OEMs to incorporate more resiliency into their preconfigured offerings and adopt best practices that ensure their equipment functions as intended.

One important way to improve the quality and resiliency of preconfigured equipment racks is to use reliable power distribution units (PDUs) with circuit protection components designed for data and telecom centre applications. After all, an equipment rack is only as good as its PDU, and a PDU is only as good as its circuit protection.

Critical role of data centre PDUs

Data centres need to fit a lot of equipment into a small space, including PDUs that send power to servers. PDUs, in turn, need circuit breakers to protect sensitive electronics from short circuits and overcurrent conditions. In these confined spaces, the risk of fires and overheating are real concerns. Selecting inferior circuit breakers can lead to equipment damage, unreliability, and dangerous situations.


A man with a laptop stands in the server room. Source: AdobeStock

An equipment rack or enclosure must be designed to deal with the physical equipment housed inside, and that means incorporating PDUs and circuitry protection that extends the life of the equipment.

As you would expect, PDUs are facing the same evolutionary demands placed upon the reengineering of data centres, which means PDUs themselves have to be more efficient and reliable and take up less space while generating less heat. As densities increase and component miniaturization becomes more necessary, PDUs also need to incorporate better circuit protection technologies.

What to look for in circuit protection components

Making sure data centre equipment is properly protected means using a PDU with circuit protection technology that can operate under the expected conditions. Important criteria to consider include:

Operational Environment: What temperature range is the PDU likely to encounter, and what levels of humidity are expected? Better components have the ability to work under greater variations in temperature and humidity.

Ease of Service: Can the PDU be reset? Does it support hot swaps of components? Does it provide a bypass capability? Are replacement parts readily available? How long is the product life cycle? What guarantees are in place to ensure long-term parts availability?

Reliability: Has MTBF been tested? What is the rated number of cycles on the components? How does the device deal with dirty power sources, load ramping, surges, and other power problems?

Safety: What type of circuit protection is in use? Are buttons and controls protected from accidental activation? Is there any method to prevent accidental disconnects? How are cables routed? Are there any sharp edges? Is there ground fault protection? How well is the PDU secured to the rack?

Efficiency: Are increased densities supported (1RU sizing)? What footprint reduction options are available? Are management and monitoring tools included? Are any types of power alarms available? Are hydraulic-magnetic circuit breakers available?

With all of these criteria to consider, it is easy to see how complex choosing the right PDU for an equipment rack can be. Nevertheless, protecting connected devices comes down to one undeniable fact, and that is the quality and type of circuit breaker involved.

Circuit breaker solutions for data centres

Circuit breakers are the most critical component of any PDU. Much like any other technology, circuit breakers have evolved and offer many different ancillary features that mark design excellence. As IT equipment has become more sensitive to power variances, surges, and so forth, circuit breakers must be up to the task and properly integrated into a PDU.

In some cases, that may mean selecting circuit breakers that are compact in nature and designed to operate in confined spaces. Those breakers should use hydraulic-magnetic circuit protection technology, and when transformer-enabled, they should be able to sense current down to a level of 1%. This enables precise current monitoring and reporting required for back billing of the actual power consumed by data centre storage and routing devices, while also facilitating load adjustments and maximum efficiency.

In other cases, circuit breakers that are designed for high power density situations may be required. Those breakers should come in low-profile form factors, use hydraulic-magnetic actuator mechanisms, and ensure rapid tripping and cooling to prevent serious equipment damage and fire. Check out our J-Series for these features as well as its wide range of delay options, including Instantaneous, ultra-short, short, medium, long, short hi-inrush, medium hi-inrush and long hi-inrush.

Designed with a common trip linkage

Depending on the intended application of a PDU, circuit breaker designs may have a dramatic impact on the suitability of that PDU. Take for example cases where it is critical to prevent manual override of a breaker in an overcurrent situation. That may mean using a tandem pole circuit breaker, which is designed with a common trip linkage ensuring that if one pole trips, the tandem pole simultaneously trips. It is also important that the breaker incorporates a trip-free mechanism, which is a safety feature making it impossible to manually hold the contacts closed during overcurrent or fault conditions.

Of course, PDUs designed for dc environments require adequate circuit protection as well. Dc-powered systems have different needs and normally incorporate high dc voltages (up to 600 Vdc), along with high amperages. Better circuit breakers for those environments employ hydraulic-magnetic mechanisms, along with permanent magnets that can create strong magnetic fields that are used by arc runners to better react to spikes and help to cool the breaker as well.


Carling Technologies, a Littelfuse brand, provides a full line of hydraulic-magnetic circuit breakers that can be configured for specific data centre applications. The compact, low-profile circuit breakers are suitable for the rigors and confined spaces found in datacom and telecom rack systems and power distribution units.




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