部落格

Keep it Safe: Overload Protection at the Rack

Posted on September 22, 2021 by Gento

This article from Raritan provides an overview of overload protection standards for rackmount PDUs.   

Lost in most discussions about rackmount PDUs and intelligent PDUs is a simple premise: their job is to keep you and your equipment safe. Newly certified ITE PDUs of any type and with more than 20 amps are required to use overcurrent protection that meets branch circuit protection requirements in accordance with the National Electrical Code, ANSI/NFPA 70. In effect, this means these products are required to have branch circuit breakers listed under UL 489, “Standard for Molded-Case Circuit Breakers, Molded-Case Switches and Circuit Breaker Enclosures,” or fuses listed for branch circuit protection, such as those listed under UL 248-5, “Low-Voltage Fuses – Part 5: Class G Fuses.” 

Using the Right Circuit Breaker Means Avoiding Short-Circuit Disasters 

In addition to UL Standard 489, Underwriters Laboratories also publishes UL Standard 1077, which is the “Standard for Supplementary Protectors for Use in Electrical Equipment.” Devices certified to this standard are considered “Supplementary Protectors” and are called “Recognized” components, not “Listed” devices (as UL 489 breakers are). UL Listed Circuit Breakers meet more stringent requirements for branch circuit protection than Supplementary Protectors with UL Recognition. UL 489 requires the breaker to be functional after being subjected to a short-circuit test. UL 1077 and the IEC standard EN 60934 allow for breakers to clear a short-circuit condition but become safely destroyed in the process. 

Circuit breakers are used in a variety of ways: 

  • They are mounted in panel boards (also referred to as building PDUs) and rackmount PDUs to protect branch-circuit wiring. 
  • They are also built into equipment to protect components and systems. Interrupting a short circuit—current flow limited only by the resistance of wiring—is a severe test of a circuit breaker. 
  • If the interrupting capacity of the breaker is not adequate, the device could literally explode. 

While that last bullet sounds a little dramatic, it is a friendly reminder that the amount of energy being harnessed in the electrical systems of most data centers, even at the rack or individual circuit level, is significant. Keep in mind UL 489 breakers can interrupt short circuits of 5,000 amps or more and UL 1077 breakers can interrupt fault currents of 1,000 amps. 

Overload Protection and Rack Mount PDUs 

If you would like more information on the topic of data center overload protection, check out our White Paper “Data Center Power Overload Protection: Circuit Breakers and Branch Circuit Protection for Data Centers”. 

Contact us here at Raritan to learn more about how our rackmount PDUs can support your power safety needs. 

Other Blog Posts

Need a Customized PDU? Raritan Can Build It for You
Posted on October 18, 2021
機架層級的IoT安全性合規
Posted on October 1, 2021
A Teaching on Supporting Higher Densities for Higher Ed
Posted on September 9, 2021
量子世界中的超級運算
Posted on September 1, 2021
Fire and Ice: Data Center Environmental Monitoring
Posted on August 19, 2021

View all Blog Posts

訂閱

近期活動

Data Cloud India
February 5-6, 2020  •  Mumbai, India
Industrial Automation
April 24, 2020  •  Tainan, Taiwan
DigiTimes Data Center Forum Taipei
May 8, 2020  •  Taipei, Taiwan
Cloud & Data Center Convention (Wmedia)
May 14, 2020  •  Manila, Philippines
Industrial Automation
May 14, 2020  •  Taipei, Taiwan

View all Events

Raritan最新新聞

Raritan 發表 MasterConsole® 數位雙電腦切換器
Posted on February 18, 2021
Legrand Data, Power and Control Division Announced as Finalist in Six Categories at DCS Awards 2020
Posted on November 9, 2020
Raritan 新款智慧機櫃控制器 (SRC) 可智慧管理資料中心與關鍵任務設施的環境與安全性資訊
Posted on November 9, 2020
Legrand India Launches Datacenter Infrastructure Solution for the addressable market size of INR 3000 crores
Posted on August 23, 2020
Raritan 推出中小型企業專用的新一代經濟型 KVM-Over-IP 切換器與序列存取
Posted on March 16, 2020

View all news