Several manufacturers, including General Electric Co., E-Mon, Itron Inc., and Wechsler Instruments, offer meters that meet the reporting requirements of the Forest Service. Many of these meters were considered before MTDC chose units to evaluate and recommend.

MTDC installed and evaluated four systems from two manufacturers:

• Electro Industries/GaugeTech (EIG)—Nexus 1250 Power Meter and Shark200 Meter
• Schneider Electric—Square D PowerLogic ION7550 and ION6200 Power and Energy Meters.

Table 1 shows the costs of the units installed at MTDC.

By choosing both less expensive and more expensive units from both manufacturers, we were able to evaluate products that addressed a range of metering and data logging needs. The higher end models could be accessed by remote computers.

An advanced power meter should at least monitor a structure's primary electrical power feed from an electric utility. The meter must have enough memory to store power consumption and power quality data at regular intervals and must connect to networks that can send data to a central server where data are archived and reports can be generated.

One meter does not provide detailed information showing how power usage is distributed among lighting, heating and cooling, computing, electrical tools, and appliances. Submeters (figure 5) on specific circuits allow power usage to be monitored on those circuits, providing information that could be used to reduce power consumption.

Figure 5—A typical low-end submeter that sends data
to a high-end meter that stores the data.

Some models of advanced meters evaluated at MTDC could import and store data from a network of more than 10 submeters. While submeters cannot perform some of the more sophisticated power quality measurements, they can provide information to an advanced meter. The advanced meter allows power usage in the facility to be analyzed.