I’ve posted a great deal on the green benefits of using DC power in the data center. In this post, I’ll discuss how data center DC power effects safety and offers an alternative to the bane of data center managers, the Emergency Power Off (EPO) button.
The EPO has its basis in the National Electrical Code, Article 645. In a nutshell, the EPO allows emergency responders to deenergize the facility to safely deal with fires and such. The EPO is not required for data centers that don’t take advantage of the goodies in 645, but how can you argue with the safety of emergency crews?
The problem with EPO is downtime due to accidental or malicious operation. Since the buttons are required to be easily available, this is an ongoing problem with EPO equipped facilities.
So, how do DC power plants eliminate the need for the EPO and keep emergency crews safe? Most DC power plants have the ability to operate the battery disconnect breaker with a separate control circuit. Simply tie this circuit to the facility fire alarm panel.
If the fire alarm panel trips due to smoke, heat, or alarm pull events, it automatically disconnects backup power (the battery string). The facility continues to run until emergency crews make the decison to interrupt the AC power (as they would in any normal circumstance) and be sure ALL the power is off.
There’s fire but the alarm panel hasn’t tripped? Simply activate a pull station for the same effect. No more hunting for the battery disconnect breaker.
Since this is a two part process, the nuisance trips of the single part EPO are eliminated, there is confirmation there is definitely a problem before any activation, manual shutdowns are still available but no longer with uncontrolled access, and there’s no more electrical hazard in an emergency. Also, removing backup power no longer means a forced full shutdown.
Green, reliable, and safe, who would have thought.
Vern, SwiftWater Telecom