Jan 23 - 29, 2006

When choosing UPS equipment how can you ensure that it will perform as expected and the information provided by different vendors is comparable? One way is to look at the European Union wide standards which govern UPSs.

UPS standards in Europe are created and maintained by an organisation called the European Committee for Electro technical Standardisation (CENELEC). This body is composed of members from each EU country as well as members from many other Eastern and Central European countries.

The UPS standard, EN50091, has three parts. Part one deals with safety requirements for UPSs and is compulsory for all UPSs sold in the EU. Part two is also compulsory and deals with electro magnetic compatibility (EMC). It has two parts - emissions and immunity. Emissions govern what levels of noise and disturbances the UPS is permitted to emit into the environment. The immunity section specifies what levels of disturbance the UPS must be able to tolerate from outside sources. The final part of the standard specifies performance. This section, which is not mandatory, provides benchmark data and a methodology on how to measure the performance and functionality of different types of UPSs and states specification methods for UPS values.

The performance standard is intended to aid buyers and users of UPS equipment in the selection process. The standard categorises the different UPS topologies:


Stand-by UPS supplies power to the load directly from utility until a utility power failure occurs. The UPS then turns on the inverter and supplies load from the battery. These UPSs are also called Off-line. These units meet CENECLEC Class VDF or VI


Line interactive UPS compensates for deficiencies in utility voltage by running the UPS inverter parallel to utility voltage when needed. The UPS output is therefore partly dependent of the quality of the utility power. Several marketing names are used for these UPSs, Single Conversion, Parallel On-line and Delta Conversion to name a few. These units meet CENELEC Class VI.


Double conversion UPS regenerates the electricity constantly. The output power is completely independent of the input power. These units are most often called On-Line UPSs. These units meet CENELEC Class VFI.

The CELELEC performance standard is an excellent aid in UPS selection, but using it does require some knowledge of UPSs and electrical systems. It is therefore most beneficial to buyers and users who are professionally involved in electrical power either as consultants, electrical contractors or facility managers.

Most UPS users, especially those buying small and mid-range UPSs, cannot afford to spend a lot of time thinking about different UPS topologies and UPS performance characteristics. Powerware has therefore taken an extra step to help in their selection procedure.

Powerware has further developed the UPS classification based on the CENELEC standard. It is based on the UPS's ability to solve different power problems. There are nine common power problems in any electrical environment. Powerware offers Series 3, Series 5 and Series 9 to address the various protection needs.


The UPSs are able to correct 3 out of the 9 power problems (Power failure, Surge and Sag). These UPSs are intended for protection of PCs and desktop workstation protection in the home and office environment. They are the most economical UPSs and due to their small size and virtually noiseless operation are ideally suited for desktop use. Series 3 corresponds to Stand-By in CENELEC classification


These UPSs are able to correct 5 out of the 9 power problems (Power failure, Surge, Sag, Undervoltage and Undervoltage). These UPSs are designed to be used with servers in an office environment. As servers are more critical than individual workstations, the higher protection level is required. Series 5 corresponds to Stand-by and Line-interactive in CENELEC classification


These UPSs are able to correct all 9 power problems (Power failure, Sag, Surge, Undervoltage, Line noise, Overvoltage, Frequency variation, Switching transient and Harmonic distortion). These UPSs are used with all mission critical electrical equipment which cannot afford to go down (servers, communication equipment etc.). Mission critical equipment both inside and outside the office environment should always be protected by Series 9 UPS. These UPSs also feature possibility for extending the battery back up time up t o several hours. Series 9 corresponds to Double-Conversion in CENELEC classification.

Both CENELEC Performance standard and Powerware 3-5-9 classifications are aimed at helping in the UPS selection. The CENELEC standard is intended for power professionals whilst the Powerware 3-5-9 can be very helpful for the less experienced UPS buyer. As a customer you should always make sure the UPS vendor can provide information about the UPSs CENELEC class and it's ability to correct the nine power problems.


A globally recognized industry leader for more than 40 years, Powerware designs and manufactures a full line of Uninterruptible Power Systems (UPS), DC power systems, power management software/connectivity products. Powerware products are typically used in networking, PC, financial, medical, industrial, voice and data communications, military and aerospace applications - wherever continuous power is essential to daily operations. Powerware is headquartered in Raleigh, NC, and is part of Eaton Corporation.

The company offers a full range of UPSs ranging in size from 300 volt-amperes (VA) for personal computers to greater than 1,000 kilovolt-amperes (kVA) for mission-critical applications including data centers, Internet service providers, and server farms. Network-connectivity devices, extended battery cabinets, power distribution modules and other power-related devices further enhance Powerware UPS hardware offerings. The Powerware product portfolio also includes a full line of DC Power Systems ranging in size from mini systems for roadside cabinets or customer premises equipment to large systems for major switching installations. Power management software and IT infrastructure management software complete the company's product line. Basic power management software provides industry-standard monitoring, alarm and shutdown capabilities. More advanced software packages offer expansive data archiving, trending and regression analysis tools with predictive capabilities. With innovative software that can predict the type and timing of possible future events, Powerware is leading an industry shift from reactive power protection to proactive power management.


Eaton Corporation is a diversified industrial manufacturer with 2003 sales of $8.1 billion. Eaton is a global leader in fluid power systems and services for industrial, mobile and aircraft equipment; electrical systems and components for power quality, distribution and control; automotive engine air management systems and powertrain controls for fuel economy; and intelligent drivetrain systems for fuel economy and safety in trucks. Today, the company classifies its business into four distinct segments, which are, by size: Fluid Power, Electrical, Automotive and Truck. Eaton has 51,000 employees, 207 manufacturing sites and sells products to customers in more than 100 countries.


GemNet is a power solutions company, providing quality power products and services. Our philosophy has always been to combine its local expertise and commitment with quality products, technical competence and the support of its principal. Since inception, it has been our goal to build deep and long lasting relationships with our customers and alliance partners by providing them top-quality power products and services. This has been the single most important success factor for GemNet, earning it the reputation as one of the leading and most professional power products and solutions companies. Today, GemNet enjoys an established track record of excellence with its customers in Pakistan and the United Arab Emirates. GemNet is the authorized distributor for Eaton Powerware's range of AC and DC Uninterruptible Power Systems, and offers a large range of specialized power related products and services. The company has local offices in Karachi, Lahore and Islamabad (GemNet Pvt. Limited) and Dubai, United Arab Emirates (GemNet Gulf).


* Service plans to fit the clients needs, including plans that cover the client's existing Power Systems and UPSs.

* Services also include: Needs Analysis, Comparative Product Analysis, Cost Justification, End-User Training, Maintenance, After Sales Support, Data/telecom center electrical contracting and site preparation

* Power Consulting & Critical Environment Site Audit (CESA): Audit of existing UPS and recommendation of a power solution. Analysis of the quality of power feeding the systems. Facility/Site inspection, identification and correction of the problem.