Picture a living room full of eager football fans watching their team's season opener on television when suddenly the power goes out. For most of us, this would mean waiting for the electric utility to fix the problem or, more realistically, racing out to watch the rest of the game elsewhere. In a few households, the owner could turn to a portable standby generator. But for those with Schneider Electric's new Square D QO Intelligent Load Center connected to an onsite standby generator, power would transparently be restored in seconds — with no action required by the homeowner.
Introduced at the January 2006 International Builder Show in Orlando, Fla., the intelligent load center eliminates the need to install a subpanel with residential standby generators. Power is automatically transferred to the backup source when the utility source is lost.
“[They] don't even have to be at home for the generator to start up or the transfer operation to happen,” says Bill Unseld, manager of product marketing and residential products for Schneider Electric, Palatine, Ill.
A joint venture between the North American Operating Division of Schneider Electric and Kohler, Wis.-based generator manufacturer Kohler Power Systems, the load center is designed to work in combination with a Kohler residential generator system. The load center operates exclusively with a variety of Kohler generators up to as large as 30kW.
The combination load center and automatic transfer switch works using sensors to constantly monitor power coming from the utility. When the transfer switch logic senses abnormal voltage or frequency levels on the incoming feed, it signals the generator to start and makes the transfer of power to the backup source. “Typical transfer time is less than 10 seconds,” Unseld says.
During this transition, the transfer switch locks out utility connection to prevent back feeding power onto the utility line. Then the pre-determined electrical loads in the home are transferred to the generator. Once utility power is restored, the transfer switch automatically reverses the process, transferring the load back to the utility and shutting down the generator.
The intelligent load center and its automatic transfer switch are sold separately so that an electrical contractor can make new homes generator-ready or opt to install the transfer switch and generator at a later date. According to the manufacturer, contractors will benefit from reduced installation time and labor costs, as the combination panel eliminates the need to install a second distribution panel. Installing the load center is just like installing any other load center, maintains Unseld, explaining that the difference lies in the installation of the field-installable transfer switch kit.
Electrical contractor and owner of G.J. Richardson Electric Service in Selma, N.C., George Richardson installed these load centers in two North Carolina homes last winter and was impressed with the simplicity of installation. “I'd say it would save at least 20% to 30% on labor, and probably cost too,” he says. “When you use this Intelligent Load Center, everything is right there in one panel. All you have to do is go straight from the generator right to the panel.”
For one retrofit installation, Richardson says he removed the old 400A meter base, replaced it with a combo 400A Square D assembly on the outside of the house, and fed two 200A panels inside. Then he rerouted the circuits for all of the primary equipment that was essential for that homeowner, including the refrigerator, lights, and a well pump.
“If [the homeowner] lost power, he had a gas furnace he could actually run in the winter time, and he could run one of the heat pumps in this particular application on his generator,” he says.
Beyond the labor savings he receives, Richardson likes the benefits this product allows him to pass on to his customers. “It's a whole lot safer,” he says. “The average homeowner is not real familiar with transferring power, and this takes all that out of the equation. It does all the work for you.”
The Square D Intelligent Load Center is now available for new construction, and its transfer switch will be available in October. Combined, the load center and transfer switch will cost about $1,600.
For more information, visit www.squared.com.
- Transfer cycle typically less than 10 seconds
- Indoor and outdoor enclosures
- 120/240VAC single phase
- Indoor: 42 circuit maximum construction
- Outdoor: 28 circuit maximum construction
- 125A maximum branch feeder connection to an alternative energy source
- Service entrance rated
- Manual override capability