Ratings of Breakers for Data Centers

Regardless of their size, data centers are a huge cost of ownership for businesses and their owners. Electrical power is now 30 percent on average of the operating cost of a data center today. Over the last 10 years, the average power requirement at a data center?s rack has gone from two kilowatts to 10 kilowatts. In order to deliver all this power efficiently and safely, IT professionals charged with managing today’s data centers are deploying power distribution units (PDUs) that are able to handle voltage above 200 volts and 30 amps. As a result, new ratings and safety specifications for breakers for data centers are ever evolving.

Breakers for Data Centers

Circuit breakers for data centers are very important to both manage power and provide a safe environment for electrical equipment, which in turn keeps property and people safe. They are mounted inside power distribution units in order to protect branch circuit wiring. They are also housed inside different types of equipment to protect valuable, and expensive, components.

The role of circuit breakers for data centers is to interrupt a short circuit, in case of some type of current flow issue. All breakers for data centers are tested and rated for short-circuit activation, however, after a short circuit occurs, the ability for the circuit to respond again might be compromised, depending on the level of the original short circuit event.

Underwriters Laboratories

Underwriters Laboratories (UL) is an independent product safety company that works to ensure safe living and working environments, specifically as they relate to electricity and power.

Different breakers for data centers can handle different levels of amps and shorts. For example, UL 489 requires the breaker to be functional after a short-circuit test and can interrupt shorts of over 5,000 amps. UL 1077 allows for breakers to be safely destroyed after a short circuit occurs.

Each circuit breaker has two different ratings for interrupting capacity. One identifies the maximum amount of current the breaker can interrupt safely and still continue working. The other rating specifies the maximum current the breaker can interrupt safely, however, as a result of the power interruption, the breaker will likely no longer function properly. These are often referred to as either “not fit for further use” or “not recalibrated after testing”.

Understanding Power Overloads

Power overloads can be quick or take place over a long period of time. This means the breaker must not trip with a short overload that can be part of the every day occurrence of using high tech power equipment. Servers are a prefect example of equipment that has this type of “short term” event on a regular basis. Breakers for data centers need to be able to handle this type of every day event. If a power overload continues, however, then the breaker should open to prevent any potential equipment damage or other electrical issue.

The ratings provided by UL are essential to running electrically safe and electrically efficient data centers.