Miscellaneous and electronic loads (MELs) consume about 20% of the primary energy used in U.S. buildings, and this share is projected to increase for the foreseeable future. Our understanding, however, of which devices are most responsible for this energy use is still rudimentary due to the difficulty and expense of performing detailed studies on MELs and their energy use. In order to better understand the energy use of MELs and the design of MELs field metering studies, we conducted a year-long study of MELs in an 89,500 sq. ft. (8310 m2) office building. We present insights obtained from this study using 455 wireless plug-load power meters including the study design process, the tools needed for success, and key other methodology issues. Our study allowed us to quantify, for the study buildings, how many devices we needed to inventory and meter as well as for how long we needed to collect meter data. We find that the study design of earlier work would not have yielded accurate results in our study building. This paper presents these findings along with a brief summary of the energy related results.