I have installed the first sensing shield on an Arduino Uno near my house’s breakers box. I finally got a 9V AC/AC transformer so I wanted to monitor my voltage, power factor and effective power usage in my house. I managed to squeeze in a power supply for the Arduino, the 9V AC/AC transformer and of course the CT inside the breaker box, but there was no room for the Arduino+Sensing shield so I placed them in a plastic Arduino enclosure.
The sensing shield is sending the data to a NanodeRF and the NanodeRF is sending it to my emoncms installation. I use a multigraph to overlay these values. The voltage readings are a bit high, but they match my digital multimer as well. In my country it should be 220V, but readings are in the 240V range. Last year we got a new grid power transformer in our block, since then voltage has been higher.
The graph shows the expected small drop in voltage when powerful appliances are switched on. Power factor has been multiplied by 100 so that is visualizes on scale. It varies a lot, I will have to research further.