Under most conditions these services require a 16S electronic meter or a 9S CT rated meter. With 4 wires being present there should be 3 elements in the metering. There are some fancy ways to do with 2 element metering but we won’t get into it here.
In the mechanical meter world the wild leg (the 208 volt L-N) needed to go to the C phase in the meter. The was due to requiring a different voltage coil for the higher voltage leg. This was also the reason for more meter forms in the mechanical world and now in the electronic world, one meter can be used in several different form applications. This presents issues at times because the NEC requires it goes on the center leg (B phase). If you find with an electronic meter that doesn’t have the wild leg in C phase most likely you don’t have an issue that requires rebill. Most electronic meters are auto voltage form 120 to 480 volts per phase. The meter should be doing registration just fine but it may give service errors on the screen which are really more nuisance than anything. There have been several asks in the industry to get rid of error in on this with the meters because in the electronic world it doesn’t really have any meaning.
For a 9S meter sometimes when a customer has the wild leg in the B phase in a CT cabinet we just wire the wild leg to the C phase of the meter. It can cause some confusion with looking at wiring after the fact but good labeling and good color coding of the wiring should keep those issues minimal.
The Upper Midwest Metering Association serves the upper midwest states of Minnesota, Iowa, Wisconsin, South Dakota, and North Dakota. We provide connections for members, utilities, meter schools, and vendors in our bi-annual meetings and continuous dialog throughout the year.