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10 Things You Need to Know Before Ramping Up to 415 VAC Power

Posted by RJ Tee on Feb 20, 2017 1:03:33 PM

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You and your team members have been thinking about switching your cabinets to 415/240 VAC. This will reduce the total number of transformers in your power path, which should in effect reduce power loss — and operating costs — in your facility.  

Hold onto your horses before getting started, though. Here are 10 things you should know before attempting this:

  1. Most international data centers are already doing it: Be prepared to answer some questions from your supervisor or facilities manager. You may receive some pushback about pumping more voltage into your cabinets. That’s because here in the U.S., most data centers are using 240/120, 208/120 or 480/277 VAC systems. 208/120V high leg delta systems are sometimes used, too. But throughout the rest of the world, 400/230 VAC power distribution setups are commonplace. And this trend is quickly spreading throughout North America, as data centers are finding they need more power to support increasing densities and workloads.

 

  1. Mind your frequency: Most North American IT devices require 60Hz to operate, meaning they require a current that changes direction about 60 times per second. However, most 400 VAC systems run at 50Hz, and so you may run into some performance issues. This is true especially with your heating and cooling systems. You’ll want to keep a close watch on this, and look to see if there is a correlation if you start experiencing quality problems.

 

  1. Determine how to measure power loss: Talk with your team members and discuss whether you want to view power loss as an overhead expense, or an IT issue. Many large data centers — like Google — consider loss from a server’s power cord to be an overhead power expense. Google, for instance, only measures its servers, networking equipment and storage systems when calculating power usage effectiveness (PUE). Make sure you and your team members are all on the same page before proceeding to eliminate confusion.

 

To that point, it’s also time to stop calculating PUE if you haven’t already done so. As we discussed in a recent blog post, the American Society of Heating, Refrigerating and Air Conditioning (ASHRAE) now has a new standard for measuring data center efficiency. And it does not include PUE.

 

  1. Plan for fault currents: By increasing your system voltage, you will increase the risk for fault currents on your network devices. Make sure that your downstream equipment has a high level of interrupting capacity, so that you avoid short circuits that could lead to unplanned system downtime.

 

  1. Follow safety precautions: By ramping up to 415/240 VAC, you will be operating a system that has more power, and more voltage. It’s not a simple tweak, but a serious change that could have major repercussions if you aren’t careful — namely serious injury or even death for IT personnel. Arc flashes, for instance — or electrical explosions — can sometimes happen when increasing power and voltage. So make sure that your staff members are well educated about the risks that come with the project, and that they are using proper safety gear in the data center.

 

  1. Ensure all devices are optimized: Most IT devices can operate between either 100 to 120 VAC, or between 200 and 240 VAC. But this is not something you want to guess about. Check each device’s nameplate rating to make sure they are capable of working safely at a higher voltage. If they can, you are golden; running devices at the higher voltages, equaling a lower current for the same power, will increase efficiencies approximately 2 to 3.5 percent.

 

  1. Watch out for higher costs: While increasing your power and voltage can save you money in the long run, it can also increase operating expenses- regardless, you are able to utilize more power at a more efficient rate. With that in mind, it’s important to monitor your system consistently in order to keep track of daily expenses.

 

  1. Temperatures may increase, too: Of course, you’ll also want to keep a close watch on your data center’s environmental conditions. This is especially important if you are running heavy workloads. Your best bet is to invest in an intelligent PDU that provides real-time environmental monitoring in addition to power metrics. Look for a solution that can send SNMP alerts, so that your team can spring to action if things go haywire in your data center.

 

  1. You will lose compatibility with 120V IT devices: Another thing to keep in mind is that some IT equipment may come with a 120 VAC NEMA power cord, which will not be compatible with a CDU in a 415/240 VAC system. You’ll need to switch over to a device that uses an IEC-based cord.

 

  1. Control is critical: The success of this operation will be determined by your ability to understand how your system is performing, and to make remote changes immediately when problems arise. Surprises will undoubtedly occur on the way, and you need to be in a position where you can react quickly.

 

Server Technology offers the Sentry Power Manager, which is a centralized, Web-based management console that you can use to manage your 415V setup. With the help of SPM, you can confidently migrate to a higher voltage in your data center safely and confidently.

 

To learn more information, click here.

 

Topics: 240/415V, efficiency

The Benefits of 240/415V Power Distribution in North America

Posted by Bob Parente on Feb 22, 2013 9:14:00 AM

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North American data centers continue to implement higher voltage power distribution to the end equipment AC power supplies at an increasing rate.  Bringing higher AC voltages to the data center rack equipment power supply modules will maximize device energy efficiency.
  • AC power supplied equipment will operate more efficiently using the highest supported voltage available.

Provisioning for increased power demand using minimal power feeds into the rack requires increased voltage, current, or both.  Using an example of a rack with a power requirement for up to 17kW of continuous current redundant power, we can determine how many power feeds to the rack (and upstream Remote Power Panel circuit protection points) would be necessary based on the power delivery system parameters (voltage, amperage, and phase).  Referencing the table below, we can see the higher the voltage and / or amperage, the greater the power availability using less conductors (power feeds into the rack).

Number of Power Feed Required Comparison to provide safety rated 17 kW

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The most common method of rack power delivery in the data center is to provide independent appropriately rated A & B power sources.  The A & B input feeds load share with a maximum of 40% capacity on A & 40% capacity on B.  This maintains an 80% maximum load (NEC Safety rated requirement) should any one side be required to carry the entire load.

Following outlines the two power distribution methods that would provide up to 17kW of continuous current redundant power with full power redundancy:
  • 208V, 60A 3-Phase [208V x 60A x 1.732 x .8 = 17.3 kW, per power feed  (Volts x Amps x square root of 3 due to line-to-line load with 2 of the 3 phases x 80% maximum safety rating per NEC].
NOTES: two3-phase power feeds (A & B) to the rack with full redundancy.  This would provide a means to maintain an 80% safety rated maximum load of up to 17.3 kW should any one side (A or B) be required to carry the entire load. 
  • 240V 30A 3-Phase [240V x 30A x 3 x .8 = 17.3 kW per power feed: Volts x Amps x 3 due to line-to-neutral load with 2 of the 3 phases x 80% maximum safety rating per NEC].
NOTES:  two 3-phase power feeds (A & B) to the rack with full redundancy.  Increasing the power by means of increased voltage without increasing the amperage (240/415V @30A) allows use of rack based power strips utilizing smaller more pliable power inlet cords with reduced size connectors as compared to that of a higher amperage rated (208V @ 60A 3-Phase) power strip.  

The majority of the implementations are for new data center builds for 240/415V power distribution. Some key points for 240/415V power distribution to the rack are:
  • Provides a means to increased rack Power densities.
  • Equipment will operate more efficiently using the highest supported voltage available.
  • Fewer branch circuits to the rack will reduce wiring, weight, & bulk.
  • Less wiring bulk increases airflow and cooling efficiency.      

Topics: power consumption, data center power, data center planning, 240/415V, power distribution, north america