Building Operating Management, April 2011 (Archived) — This webcast provides not only an overview of the necessary considerations in developing high-availability– and green — facility infrastructures, but also addresses the role of short- and long-term sustainability planning and its impact upon data center financial liabilities. Learn about emerging trends, options and alternatives in data center development, and get updated information regarding LEED requirements as well as local, regional and national regulations that will affect the future of data center design, construction and operations.

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Key takeaways from this webcast include:
* Identifying data center green initiatives
* Understanding reliability vs. redundancy vs. uptime
* Clarifying the role of LEED in data centers
* Learning the cost impacts and trends in greening data centers

December 13-15, 2011

Las Vegas, NV

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Thursday, February 3, 2011
1:00 PM, Central Standard Time

The emergence of the smart grid will have three substantial impacts on data centers. One will be the need for more data centers to support the massive amounts of information and data processing that the smart grid will engender for utilities, energy service providers, and marketers. The second will be how data centers themselves interact with the smart grid as loads responding to grid conditions, microgrids, and demand-response programs without compromising mission-critical cooling and operations. The third will be a boost in efforts and incentives to increase the energy efficiency of data center facilities and equipment.

This Webcast will provide an overview of the smart grid’s anticipated information architecture and how data centers could interact with the smart grid through automated demand response, microgrids, and virtual power plants. Also covered will be an update on public/private efforts to improve the energy efficiency of data centers.

This Webcast is free and one (1) AIA learning unit (0.1 CEU) (or 1 PDH) will be provided upon successful completion of exam following the Webcast.

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When you are responsible for superior service for more than 10 million shareholders and 172 institutional clients, you can’t afford to blink.  With more than 3500 employees and six computerized service centers in Massachusetts, London, and Tokyo, Putnam Investments has invested in emergency/backup power systems for all its facilities to assure continuity of service to its customers.

Putnam is one of the largest money-management companies in the world, offering mutual funds retirement plans, college savings plans, insurance products and institutional portfolios.

As the company grew in the late 1980s and early 1990s, Putnam learned about the differences in backup power systems firsthand.  Chronically malfunctioning switchgear installed in 1986 at the company’s first data center led management to reconsider its choice of equipment when planning the emergency/backup system for its headquarters in Boston’s Post Office Square.  Installed in 1990, this new system included a single Caterpillar 800 kW generator and three open-transition automatic transfer switches manufactured by Russelectric® Inc. in nearby Hingham, Massachusetts.

These equipment changes were the result of a scoping process in which Putnam executives and S.B. Sager Associates, the system designer, investigated not only the equipment but also the capabilities, reputation, and performance history of various system suppliers.

“Russelectric® was one of three firms we looked at,” says Barry Mosher, Putnam’s Project Engineering Manager.  “We knew what we wanted the equipment to do, and we compared the failure histories, service records, and so on.  Russelectric® seemed the best choice; there was no question about it.”

Russelectric® designs, builds, commissions, and services switchgear and power control systems for hospitals, data centers, ISPs, airports, and other critical facilities.  Systems can provide sophisticated control functions such as emergency/standby power using either open-transition transfer or live-source, closed-transition transfer; cogeneration; prime power; peak shaving; load curtailment; uninterruptible power; and utility paralleling.

Russelectric® also supports its customers with 7 x 24 field service.  Mosher had heard about this, but in 1991 when one of his transfer switches developed a problem, Russelectric®’s response made him a true believer.

“I had to shut the building down that weekend,” he recalls.  “If I couldn’t fix the switch, we’d be out of business.  I called the [Russelectric®] toll-free field service number and was told the engineer in charge would be paged.  He called back a few minutes later from his daughter’s wedding!  He understood the jam I was in and said he would be there in about half an hour.  He was still in his tuxedo when he showed up.  He quickly fixed the switch and checked the other switches.  I was so impressed!  And I never even got a bill.  That day I learned firsthand that if there is ever a problem, Russelectric® will fix it and fix it right.”

With the growth of the financial industry in the 1990s came the realization that a power outage could badly hurt business.  Putnam’s concerns included more than inconvenienced customers and reduced employee productivity.  The company was concerned about the outright loss of electronic data as well as its ability to conduct routine daily tasks.  Large numbers of checks and statements have to be processed on time.  Other documents and publications have to be printed and mailed on schedule.  Putnam sells all its retail funds through financial advisors, so there are large numbers of inbound calls and e-mail messages from shareholders, financial advisors, and banks in addition to outbound communications from Putnam’s marketing and support staff.

To keep up with its rapid growth, Putnam built new facilities in three Boston suburbs, including Franklin and Andover, between 1994 and 2000.  Designed for each building and installed during construction, a 3000 kW backup power system includes three Caterpillar generators and Russelectric® closed-transition paralleling switchgear.  The backup power system at Putnam’s headquarters was upgraded to 1500 kW and supplemented with a web-based monitoring system that captures data (even from the London and Tokyo facilities) for analysis later.

The Russelectric® power control systems in all four Putnam facilities have redundant programmable logic controllers (PLCs), which coordinate the systems and can switch a facility off the grid to generator power whenever there is a problem.  The controls constantly monitor the utility feed.

“Before we renovated each new building, we conducted a fresh scoping process,” Mosher explains.  “We weeded out the average vendors; we wanted the highest quality we could get.  We looked at competitors’ services, equipment, capabilities, and failure rates, and every time we went through this evaluation process, Russelectric® emerged as the leader — the best value for the dollar.”

In the event of an unforeseen power loss at any of the three suburban facilities, Russelectric® closed-transition switchgear will automatically start the generators, parallel their outputs, and pick up loads in order of priority.  While this entire process takes only about 20 seconds, that is still long enough for computers to “crash.”  With so much at stake, Putnam also invested in uninterruptible power supply (UPS) systems to prevent even the slightest power blink.

Because data centers need absolutely pure power, Putnam is taking no chances.  The suburban power lines that feed these centers are strung between poles and are subject to damage from storms and motor vehicle accidents.  To smooth out any irregularities or anomalies in the power coming into its three suburban facilities, Putnam runs the utility feeds through its UPS systems.  This conditions the utility power and eliminates the damaging effects of harmonic distortion and brownouts.

As with the company’s disciplined scoping process, Putnam’s care is evident in its precautionary pre-storm transfer protocols.  Although the reliability of the utility feed to Putnam’s Franklin facility has since improved, from 1994 to 1999 it failed an average of 14 times per year, with outages averaging 2-3 hours each.  So today, whenever a thunderstorm, blizzard, or ice storm is predicted for the suburbs (4-5 times a year), maintenance personnel use the Russelectric® equipment to parallel the utility feed and the emergency generators and to transfer to emergency power before the storm hits.  Each system has enough fuel to run for 10-12 days if necessary.  In Boston, however, most power lines are underground, utility power is more reliable, and outages are rare, so such precautions are unnecessary.

Because the closed-transition system design transfers each facility’s loads seamlessly from utility feed to backup generators, Putnam can test the systems on a regular basis without the slightest impact on operations.  In addition to the pre-storm transfers, Putnam exercises each of its suburban systems twice a month, during a workday, for four hours.  Every quarter they test them for eight hours.  Neither customers nor employees ever notice these tests.

Under contract, Russelectric® takes care of routine maintenance on the Putnam facilities three times a year and trains Putnam employees in the use of the equipment.

“Russelectric®’s training is conducted by seasoned professionals,” says Mosher.  “But who would expect anything less?  When you tour their plant, you see that every employee takes pride in the Russelectric® name.  The customer is #1, and that comes across in their R&D, their service, and their overall attitude.”

Healthcare Network Offers Glimpse of the Future of Backup Power

Bassett Healthcare, based in Cooperstown, New York, is noteworthy not only for its top-quality patient care, but also for its self-sufficiency.  With more than 270 physicians on the payroll (an unusual closed-group practice), Bassett operates a teaching hospital, a research institute, and a network of regional clinics serving eight counties in upstate New York. All of its 24 facilities are protected by emergency backup power systems that go beyond the capabilities of most other hospitals — all using equipment designed and built by Russelectric® Inc.

In August of 2003, when a surge of electricity to western New York touched off a massive blackout affecting eight states in the Northeast, Midwest, and parts of Canada, Bassett was an island of light in a sea of darkness — up and running on its backup system.  The company’s “flagship,” the 180-bed Mary Imogene Bassett Hospital in downtown Cooperstown, played a key role by feeding the community, accepting refrigerated vaccines from county offices that had lost power, and providing other services for competing healthcare institutions that didn’t have backup power.

Bassett is even more secure today, thanks to a 2004 upgrade/expansion that added generating capacity and more capabilities to its advanced emergency power system.  Much of the credit goes to Joe Middleton. Middleton, Bassett’s forward-thinking vice president for corporate support services and facilities planning, has a degree in electrical engineering and once taught at the university level.  His knowledge and experience helped him guide Bassett’s board of directors through some tough decisions and significant financial investments to the enviable position they find themselves in today.

“Power outages are common,” says Middleton.  “But it’s not just a reliability issue; it’s a matter of system redundancy – we’re in a rural area with a single electrical feed and no natural gas service, so it became necessary to create our own secondary power source.”

Although hospitals are required to have an emergency power system for critical loads, many are located in communities with a second source of normal power.  Some are even served by two electrical utilities.  The National Fire Protection Association (NFPA) code sees this as the ideal, stating: “For the greatest assurance of continuity of electrical service, the normal source should consist of two separate full-capacity services, each independent of the other.” [NFPA 99 2005 ANNEX A.]

Bassett employs 2800 people, more than the population of Cooperstown, and sees about 1000 outpatients a day on top of regular admissions.  While management’s first concern is how to provide the best patient care, reliable backup power has a fiscal benefit as well.  Middleton estimates the loss of power for eight hours would amount to a revenue loss of $1,000,000.

Bassett isn’t taking any chances.  The default mode of the paralleling gear for their backup power system meets the requirements of the NFPA’s National Electrical Code (NEC), providing emergency power to loads that supply critical services for life safety plus the HVAC system and some other equipment – the typical hospital emergency power system.  However, that is only the beginning for Bassett’s system, which ensures that all elevators will also keep running and then, five minutes after the beginning of the outage, ramps up two additional generators to restore full power to the hospital and 15 other buildings.

In an operating room, for example, this can make a big difference.  The NEC says only a certain percentage of electrical receptacles (outlets) in an operating room (OR) must be on emergency power, not all of them.  “You can’t count on two hands the number of computerized devices in our cardiovascular OR,” says Middleton.  So at Bassett, five minutes after a power loss, not just the receptacles prescribed by code, but all receptacles are live again.  At that point, Bassett facilities are energy independent, generating all their own primary power.  The system can back-feed and feed around any fault on the campus.

But that’s not all.  Another backup system, entirely separate and distinct, ensures a continuous power feed to Bassett’s data center, which is also on the Cooperstown campus.  This system, which has its own redundancies, allows no power interruptions at all.  These days, the loss of computer access to patient drug histories, digital radiology films, and other electronic records would be a serious setback for doctors, nurses, and ultimately patients.

An advocate for the extra backup he brought about at Bassett, Middleton observes, “As healthcare technology becomes more and more sophisticated, concurrent with the increased focus on expense control, the continuous delivery of medical information is critical.  A reliable power system really needs to be a bottom-line calculation.  Unfortunately, most healthcare facilities have not realized this yet.”

In the 1980s Middleton worked for the Carle Foundation Hospital in Illinois.  When, as part of that hospital’s expansion program, management decided to consolidate and centralize their power distribution system and parallel their sources of emergency power, Middleton was involved in the selection process for the design, manufacture, and installation of the necessary switchgear.  Before long, one company — Russelectric® Inc. — stood out for both their products and service.

Based in Hingham, Massachusetts, Russelectric® designs, builds, commissions, and services power control systems for hospitals, data centers, Internet service providers, airports, and other mission-critical facilities.  Systems can provide sophisticated control functions such as emergency/standby power, peak shaving, load curtailment, utility paralleling, cogeneration, and prime power.  All systems are supported by the company’s factory-direct, 24-hour field service.

Impressed by Russelectric®’s post-installation support services as well as by the quality, reliability, capability, and adaptability of its equipment, Middleton recommended the company when he came to Bassett Healthcare in 1988.  Bassett made Russelectric® its sole-source supplier for emergency backup power equipment.  Nowadays, whenever Bassett decides to design a new system or modify an existing one, it invites Russelectric® to sit in on all planning sessions, beginning at the very start of the preliminary planning phase.

In 1990 and 1991, Bassett asked Russelectric® to design, build, and install switchgear synchronizing three 900 kW, 480 volt generator sets for the main campus in Cooperstown.  Upon loss of utility voltage, this system starts and synchronizes the three generator sets, and automatic transfer switches transfer the emergency load to the generator source.  Upon return of utility power, after a time delay to make sure the utility source is stable, the transfer switches re-transfer the emergency loads to the normal source.

Everything worked so well that years later, when it was time to upgrade/expand the system, there was no question who should do it.  “We stuck with Russelectric® because we needed reliability and flexibility of control,” says Middleton.

In 2004 Bassett upgraded the controls of the paralleling and transfer gear installed in 1990/91 and added two medium-voltage gensets (2 mW each) capable of generating 12.47 kV.  Installed on a primary bus, these are linked to and parallel with the three original gensets.  For an overview of the system, see Figure 1.

Russelectric<sup>®</sup> Drawing

Figure 1 – Bassett Healthcare’s emergency power system is programmed for two stages.  If the utility feed is lost, the Russelectric® switchgear transfers critical life/safety loads to three 480 volt generators.  Five minutes later, if the utility feed is still unavailable, two 12,470-volt generators kick in, restoring full power to the hospital and 15 other buildings.  When the outage is over, the system gradually retransfers power to the utility in the reverse order — first from the two larger generators, then from the three smaller ones.


With these upgrades, if the normal utility feed is not restored in five minutes, the Russelectric® equipment switches to the Bassett system as the primary power source (Figure 1).  Special controls in the paralleling switchgear and transfer switches lock the equipment in the emergency position so it doesn’t roll back to normal.  Then, when a tie breaker is closed, the system begins back-feeding through a 2000 kVA transformer (480 volts secondary, 12.47 kV primary) to generate enough primary power to feed the entire Cooperstown campus.

“In a sense, we’ve spoiled people,” says Middleton.  “Our employees have become accustomed to continuous full power; they become very anxious with any transient outages.  We’re seriously considering adjusting the timing circuit to reduce the delay from five minutes to just two minutes.”

When the normal supply voltage returns, the system, after a preset time delay, transfers all building loads, in the selected transition mode, back to the normal source.  Once initiated, the retransfer sequence occurs in two stages.  In the closed transition mode, the 12.47 kV generators synchronize with the utility power source, close the 12.47 kV utility breaker, transfer the load gradually to the utility source, and then open the 12.47 kV generator tie breaker.  Once the 12.47 kV generators have transferred their load, the switchgear controls allow the 480 V transfer switches to retransfer to their normal position.  The engines will continue to operate unloaded for a cool-down period.  All controls are then automatically reset, in readiness for the next operation.

The Russelectric® switchgear can also be programmed for baseload peak-shaving.  Thanks to a lucrative agreement between Bassett Healthcare and the regional power company, Bassett’s backup power system pays for itself over time.  An “interruptible power contract” gives the utility permission to drop Bassett from the regional electrical grid (with advance notice) during periods of peak demand.  In return, the utility pays Bassett, at a rate much higher than what Bassett pays for its normal feed, for every megawatt Bassett generates while off-line.

“It’s great for us,” says Middleton.  “We’re off the grid for a few hundred hours a year, mostly in the summertime, when the power we generate is of higher quality than what we get from the utility.  It’s rock-solid, with stable frequency and voltage.  But on the grid, with all the air-conditioning demands, we see large switching transients as new power sources are switched in and out.”  Bassett also has the capacity to export power to the grid, although they have never been asked to do so.

Middleton makes sure he has 45,000 gallons of less-polluting, low-sulfur oil stored on site for the generators.  The two largest generators consume 280 gallons an hour when operating — 6,720 gallons every 24 hours.  With the three older, smaller generators operating concurrently, Bassett could burn 8,000 to 10,000 gallons of oil a day just to power the main campus.  Due to improvements by the manufacturer (Caterpillar), Bassett’s two newest generators, the largest ones, produce fewer emissions together than one of the original generators purchased in 1990.  All of Bassett’s generators are rated and permitted for continuous use if necessary.

Today, in addition to the main facility, every Bassett clinic has its own Russelectric® automatic transfer switch for backup power.  Bassett maintains 30 generators in all.  “When you look at a Russelectric® transfer switch, you can see that the quality of the bussing, the control wires, the layout, etc. is dramatically better than that of competitors’ switches,” says Middleton.  He estimates that 16 Russelectric® transfer switches and one set of paralleling gear, all of which were installed almost 18 years ago, will last another 10 years.

“At Bassett, we look at utility infrastructure as the core support element for all our other initiatives,” Middleton explains.  “If the infrastructure is flexible, and adaptable, you can build on it.  But to do that, you need to partner with a company whose systems are adaptable and reliable, a company that is nimble and service-oriented.  Russelectric® is both.  We depend on Russelectric® field service for everything except routine daily maintenance.  When we have issues with our system that are beyond our local capabilities, no matter how complex, Russelectric® is there without delay — their service is timely and spot-on.”

“Russelectric® has been a true partner with us from day one,” Middleton continues.  “Their top-notch engineers have helped us through problems, creating unique solutions.  It’s been a great relationship.  Russelectric®’s focus is on the design and sale of industry-leading products, but they should sell their services too.  They are a talented, creative group of people, and they offer exceptional engineering capabilities and services.  After all, when you invest in a power control system you’re buying much more than gray boxes!”

New 30-Cycle Transfer Switches Simplify Selective Coordination

By John Stark, Sales & Marketing Specialist


Recent changes to the National Electrical Code® (NEC) require the selective coordination of overcurrent protective devices at hospitals and other mission-critical facilities. Transfer switches with 30-cycle closing and withstand ratings dramatically simplify designing to that requirement.

Selective Coordination Requirements

Selective coordination was first required by the NEC in 1993 for elevator circuits. Amendments to the Code in 2005 and 2008 strengthened the requirements and expanded them to include emergency and legally required standby systems, as well as critical operations power systems (COPS).

Selective coordination, as defined in the 2011 NEC, Article 100, is the “localization of an overcurrent condition to restrict outages to the circuit or equipment affected, accomplished by the choice of overcurrent protective devices and their ratings or settings.”  It is a complicated process of coordinating the ratings and settings of overcurrent protective devices, such as circuit breakers, fuses, and ground fault protection relays, to limit overcurrent interruption (and the resultant power outages) to the affected equipment on the smallest possible section of a circuit.  In other words, in a perfectly coordinated power system, the only overcurrent protective device that should open is the device immediately “upstream” from the circuit/equipment experiencing an overcurrent condition.

UL Standards and Testing

Underwriter Laboratories (UL) Standard 1008 is the industry-accepted standard that establishes the criteria by which automatic transfer switches are listed.  The listing process includes passing tests for closing and withstand short-circuit values.  Switches may be listed under several different testing protocols, including:

  • Testing with a specific overcurrent device so that the listing is dependent on use of that device or another with identical or faster time/overcurrent curves.  While this approach makes it easier for the manufacturer to pass testing, it actually complicates the process of selective coordination for the design engineer.
  • Testing for a 3-cycle fault duration.  A switch passing this test is considered to be coordinated with any molded-case circuit breaker capable of interrupting the test closing and withstand value.  This test is more stringent, but in no way simplifies selective coordination.
  • Testing for a specific amount of time beyond 3 cycles to establish a short-time rating.  To pass this test, a switch has to close in on and withstand a fault current for the specified test duration.  Close and withstand for 30 cycles is considered to be coordinated with any circuit breaker having only short-time overcurrent protection (not instantaneous).  A 30-cycle-rated switch therefore eliminates a host of coordination considerations and dramatically simplifies the entire selective coordination process.

If transfer switches are being protected by circuit breakers with short-time overcurrent protection only, and the switches have only 3-cycle closing and withstand ratings, they are not properly coordinated with their protective breakers.  Under these circumstances, transfer switches with 30-cycle ratings are needed to properly coordinate.

Error and Trial

Selective coordination is best done on the drawing board, at the beginning of the design process.  Although achieving genuine, documented selective coordination as defined by the NEC can be time-consuming and expensive, flawed selective coordination is even more so.  To comply with requirements, a selective coordination plan must consider — for every pertinent circuit — the full range of maximum available overcurrents, including overloads, all types of faults, and short circuits. As daunting as the process is in theory, it is even more difficult in practice, complicated by differences in the ratings of overcurrent devices from one manufacturer to another.  Obviously, choosing a supplier who offers a full line of sizes of a particular device, whether protective device or transfer switch, also makes the coordination process much easier.

Many contracts and code enforcement authorities require a study to evaluate the pertinent circuits and confirm that the protective devices have been selectively coordinated.  Performed after construction, such studies are a minefield for systems that were not designed carefully in the first place.  Once a system has been determined to be non-compliant, redesigning it and replacing various components can be extremely costly and time-consuming.  Even if proper protective devices are installed as a corrective measure, the cable, bus, or conduit ratings may not be adequate.  Or a higher-rated transfer switch or new panelboards may be needed, requiring extra mounting space.  Since a change to one component often affects others, new calculations are necessary to see what else must be replaced.  Such retrofitting to obtain a certificate of occupancy is a design engineer’s nightmare.

Numerous modifications of the NEC requirements have been adopted by local and state governments with varying degrees of enforcement, but let designers be forewarned: It is far better to err on the side of too much protection than not enough.  The specifier might be called upon to prove that the time-current curves for circuits in his/her selective coordination scheme comply with the NEC by not overlapping at the available fault current.  Even in a locality where selective coordination requirements on the books are not enforced, a specifier and his/her engineering firm could be found liable for injuries suffered due to inferior selective coordination — for the life of the building!  So, needless to say, selective coordination should also be done with an eye toward future changes in or the expansion of the power system.

Hold That Line

In a selectively coordinated electrical system using circuit breakers, the breaker for every load circuit must have the proper ratings, interrupting capacity, and settings for the point at which it is installed, based on the highest potential overcurrent from either power source (normal or backup).  Progressing “upstream” through the circuit paths, from the smallest load branch circuit all the way to the normal and backup power sources, the specifications of a true selective coordination plan must ensure that every circuit breaker has a higher overcurrent rating and a longer time-delay than the one below it, so that every overload/fault will be cleared by the breaker farthest “downstream” (the breaker immediately “upstream” of the problem).

Today, most transfer switch designs have only 3-cycle closing and withstand ratings.  The ability to withstand fault current for 10 times that duration (one-half second) necessitates that 30-cycle transfer switches are mechanically stronger by orders of magnitude.  Because of its function — switching from normal to backup power and back again — a transfer switch is obviously in a key location, and its ability to withstand a fault condition is vital to supply power to the served load.  In the event of a fault, a transfer or bypass/isolation switch that can withstand 30 cycles of overcurrent is like a sturdy defensive lineman in a football game.  Holding the line long enough to allow the coordinated overcurrent protection to interrupt the fault, a 30-cycle switch assists in protecting downstream equipment, such as expensive medical devices.

Another major benefit of 30-cycle transfer switches is the extra capacity they provide for later expansions of electrical systems.  The design phase of a renovation that upgrades available fault current or replaces overcurrent protective devices will proceed more smoothly if 30-cycle switches are already installed.  For example, many hospitals are upgrading their power systems to supply backup power to more loads.  In the past, the typical hospital backup system covered only NEC-required essential loads (typically only 25-30% of the hospital’s total connected load).  Recently, the trend is to add the hospital’s HVAC system to the backup system to reduce patient discomfort (and perhaps even save lives) in the event of an extended outage.  Medical imaging machines are also being added, and as hospitals transition to electronic medical records they often wind up creating their own mini data centers, where computers must not crash.  Today, a hospital’s standby electrical load can be as much as three times what it used to be — 75% or more of its total connected load.

Another example is today’s data centers, many of which are being designed and built on a modular basis.  Through the selection of and standardization on specific types (and even brands) of servers, cooling equipment, etc., data center designers have significantly simplified the process of modifying these facilities to accommodate changing needs, or expanding them to accommodate growth.  Yet, if the selective coordination process is based on current needs only, there will be little flexibility in the power control system for such changes or growth.  And ensuring that the power system complies with selective coordination requirements after it has been reconfigured or expanded may require far more time, effort, and expense than the changes themselves.  In many cases, investing more today in equipment that exceeds current requirements will dramatically simplify selective coordination efforts that result from future growth.

Proceed With Caution

Several things should be taken into consideration when selecting a 30-cycle transfer switch.  With the right switch, the additional security and system design simplicity offered by a 30-cycle closing and withstand rating can become reality.  Asking a few important questions can make a difference.

Does the manufacturer offer a full line of 30-cycle transfer switches?  If so, the specification of a switch is simply a matter of its continuous current rating and is not complicated by gaps in the manufacturer’s product line, or by the necessity of specifying a much higher continuous-rated switch than the circuit would normally require. 

Has the 30-cycle transfer switch been tested according to UL standards, and is it UL listed and labeled?  The switch’s closing and withstand rating must be a performance value based on actual testing to UL Standard 1008.  Because the 30-cycle closing and withstand test is optional under UL-1008, specifiers and purchasers of 30-cycle switches should carefully scrutinize the presentation of any manufacturer’s 30-cycle ratings to be certain that they are based on actual testing by UL and that the switches are UL listed and labeled.  This listing must include a close-on rating.  Withstand ratings without concurrent close-on ratings are not adequate.

Cost is always a consideration in the choice of any piece of equipment.  In the final analysis, however, a transfer switch is a key component in an emergency/backup power system designed to protect lives and/or vital assets.  Since the switch serves such a critical function in the system — for both normal and emergency loads — and since the potential losses from any malfunction are so great, the cost of the switch should be secondary to its performance.  With this in mind, system designers and owners should insist on the best switch they can find.  And given the robustness of its design and construction and its proven ability to withstand 30 cycles of punishment, a 30-cycle-rated switch makes perfect sense.


The 30-cycle transfer switch holds tremendous promise as perhaps the single most cost-effective and simple solution to the complex challenges of selective coordination.  The right 30-cycle switch can simplify a backup power system’s design and offer more reliable protection.  Plus, it provides unmatched flexibility for future system upgrades and expansion.

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Meet the needs of a power-hungry world with the right control switchgear.

By John Meuleman, Vice President, Sales & Marketing

With daily advances in information technology and other processes and services, the world is becoming a more complicated and power-hungry place. Many industries and services have become increasingly more dependent on a continuous, uninterrupted supply of electric power. However, a continually shrinking electric generation margin reduces the reliability of utility-provided power.

Consequently, the use of backup power control systems and generator control switchgear has grown and will continue to grow—in number, capacity, and complexity—in the coming years. A savvy specifier considers many factors to make sure such equipment performs as needed and its service life is not only long, but virtually trouble-free.

Some facilities cannot be without power for extended periods, but can still tolerate a short outage. For such facilities, a backup power system can be fairly simple. In other applications, however, even a momentary interruption of power could be disasterous. To avoid this, systems should include an uninterruptible power supply (UPS) system to prevent even the slightest “blink.” Generator control switchgear also can be specified to allow closed-transition retransfer or test without power interruption when both sources are available.

Generator control switchgear, typically used as part of a multi-generator electric backup power system at a mission critical facility, should have a life expectancy of at least 15 years. However, another important consideration for maximizing the life expectancy of the switchgear is the possibility of future load growth. Don’t just focus on immediate needs.

When extra capacity is specified, future expansions/upgrades can be accommodated more smoothly and at a much lower cost. For example, a hospital’s standby electrical load today can be three times what it used to be—75% or more of its total connected load.

Construction and components

Regardless of the switchgear’s application, the quality of its construction is key. Start with the cabinets, which should be fabricated from heavy-gauge steel with welded reinforcing gussets for strength and rigidity. For many geographic locations, equipment must be built and tested to withstand a seismic event per International Building Code (IBC) requirements. Enclosures should be protected with a corrosion-resistant electrostatic powder coating.

Inside, the construction of the switchgear should be durable. Switchboard wires should be flame-retardant and should have permanent sleeve markers at both ends. The best wire runs are custom-assembled on chassis (not pre-manufactured) and should include extra wires for faster, simpler repairs and future expansion. Cage clamp-type connectors provide sustained, secure control wiring connections.

Busbar should be formed, cut, and punched before being silver-plated, to ensure integrity of the plating. If the manufacturer buys pre-plated bus and forms it later, the process of bending it can crack the plating and expose raw copper. This can reduce conductivity and cause problems with corrosion and overheating, adversely affecting the performance of the whole system. Where insulated bus is used, the insulation also should be applied after the busbar is formed.

Switchgear should be built and tested to the highest Underwriter Laboratories (UL) requirements such as UL Standard 1558 for switchgear 600 V or less, and the UL category for medium-voltage switchgear (“Circuit Breakers and Metal-Clad Switchgear Over 600 V”). The withstand rating should be a performance value based on actual testing. Keep in mind that, for applications in which the utility and generator sources are paralleled, the withstand and interrupting capacity of all breakers must be greater than the sum of the fault capability available from both power sources.


Programmable logic controller (PLC)-based digital controls should provide automatic starting, synchronizing, and distribution of standby power upon detection of loss of the utility source. A fully redundant PLC will ensure fail-safe operation. Should one PLC fail, the other one will automatically take over systemwide control. Manual start, paralleling, and load controls are also good ideas in case automatic control is lost.

A color touchscreen operator interface will permit system monitoring and parameter selection on-site. Custom supervisory control and data acquisition (SCADA) will allow for remote monitoring, real-time and historical trending, comprehensive reporting, and remote alarm management. In many cases, the SCADA system for the backup power system can be interfaced with a building’s energy management system and other systems via TCP/IP or other Ethernet protocols—to provide a comprehesive overview of power quality and usage and to document energy usage trends and savings.

Long-term considerations

Other concerns are operator safety and ease of maintenance/troubleshooting. Generator control switchgear should have grounded, separately accessible compartments with drawout power circuit breakers located in their own compartments. Controls should be segregated from power bays, and only control voltages should be available in control compartments. For medium-voltage applications, the main bus joints and power connections should be insulated with preformed boots.

A purchaser of generator control switchgear should select a supplier that specializes in the field. When comparing switchgear suppliers, it is best to consult some of their previous customers to learn their track records. A supplier that is experienced in designing complete switchgear systems can contribute important ideas regarding control schemes, sequences of operations, power transfer options, and installation. A top-quality supplier should be able to provide a comprehensive guide specification that deals with most of the considerations discussed here—a specification that can be easily tailored to a customer’s unique requirements.

Negotiate a good warranty, too. A supplier that backs its switchgear with a two-year warranty probably builds it with better components than a supplier offering only a one-year warranty. A longer warranty also may help reduce the lifecycle cost of the equipment.

Needless to say, it also helps when the supplier is a service-oriented company. Factory-direct field service is preferable because the technicians are intimately familiar with the equipment, are aware of the latest updates, and have easy access to spare parts. This facilitates equipment repair and reduces downtime.

Managing cost

In some cases, generator control switchgear can actually produce a revenue stream of its own, thus defraying a portion of its lifecycle cost. In fact, standby power systems now are frequently used for peak shaving, with the system’s generator controls providing automatic operation. Furthermore, many utilities offer an “interruptible power contract” that gives the utility permission to drop the customer’s facility from the electrical grid (with advance notice) during periods of peak demand. In return, for every kilowatt the customer generates while offline, the utility pays the customer a rebate at a rate that, in some cases, is higher than what the utility charges. In certain cases, the facility can get an electricity cost reduction just for being able to provide load-curtailment operation, even if never called upon to do so.

Intitial cost is always a consideration. In the final analysis, however, the lowest first cost solution may not be the lowest total cost solution once installation, commissioning, and maintenance are considered. And, when the switchgear or power control system will be protecting lives (such as at a hospital or airport) or vital electronic records (such as at a data center), the potential losses—in terms of life or money—from an equipment malfunction can be substantial.

Author Information
Meuleman is vice president of Russelectric® Inc., which designs, builds, and services on-site power control systems. Meuleman has more than 30 years of experience in emergency/backup power systems for mission critical facilities. He holds a degree in electrical engineering and is a member of IEEE, AEE, and NFPA.

Link to Publication Website

Building Operating Management, March 2010 (Archived)

In this 75-minute Webcast presented by Bill Kosik, energy and sustainability director for HP Critical Facilities Services, attendees will learn the fundamentals of ensuring a reliable, energy-efficient data center, including:  the latest on the Energy Star standard for data centers; a review of current benchmarks, including power usage effectiveness (PUE) and data center infrastructure efficiency (DCIE); and the impact of LEED on greening data center operations.

Russelectric® custom designs and manufactures power control and synchronizing switchgear systems in low and medium voltage ratings for single- and multi-unit on-site power generators.  In addition to emergency power, system designs may include a variety of sophisticated control functions such as peak shaving, load curtailment, and utility paralleling for both open transition transfer and live-source closed transition transfer.  Closed transition transfer allows retransfer and system testing without disturbing the load.  Prime power/cogeneration systems are also available.

Systems include PLC controls for automatic prime mover starting and stopping, prime mover status and alarm annunciation, synchronizing, and priority load control.  Other features, such as load demand control for fuel management, are available.  Systems include sensors to monitor volts, amps, watts, frequency, and other pertinent electrical power data of individual generator sets and the overall system.  Controls can be furnished for any type of prime mover, including diesel engines and gas, steam, or hydro turbines.  Custom system integrating SCADA and simulation are also available as options. 

All systems are UL listed and are designed and built in accordance with ANSI, IEEE, and NEMA standards.

Because reliable electric power is required for proper operation of security equipment, the threat of terrorism makes any facility vulnerable to a loss of power. Russelectric® power control systems provide the emergency/backup power needed to keep critical security equipment up and running in the event of a loss of utility feed.

With the threat of terrorism, security systems and equipment such as specialized sensors and alarms (smoke, fire, heat, motion, pressure, contaminant, etc.); optical scanners for identification (badge, iris, or fingerprint readers, etc.); video surveillance systems; emergency lockdown systems; fire-suppression and sprinkler systems; explosion-suppression systems; and ventilation systems that automatically isolate contaminated areas have become commonplace. Without an emergency/backup system, the loss of utility feed for even a short time could render such equipment useless and compromise the security of a site. Russelectric® custom designs and manufactures low- and medium-voltage on-site backup power systems with single or multiple generators. These systems will automatically pick up critical loads if normal power is lost, to keep security equipment on line and help ensure site security.

To ensure a continuous flow of power, Russelectric® PLC controls automatically start and stop prime movers, annunciate prime-mover status and alarms, and control priority loads. Systems also include synchronizing switchgear and sensors to monitor pertinent data from generator sets and the overall system. Optional control capabilities include load demand (for fuel management) and integrated SCADA and simulation. Russelectric® furnishes controls for any type of prime mover, including diesel engines and gas, steam, or hydro turbines.

In addition to emergency power, system designs may include a variety of sophisticated control functions such as cogeneration, peak shaving, load curtailment, and utility paralleling for both open-transition transfer and live-source, closed-transition transfer. Closed-transition transfer allows retransfer and system testing without disturbing the load.

All Russelectric® systems are UL listed and are designed and built in accordance with ANSI, IEEE, and NEMA standards.