The ESRI provided electric utility network fundation doesn't include a low voltage electric meter as part of any of the Asset Groups in the Device Class. There is a Low Voltage Service Asset Group but it's not for meters.
Then, what is the recommended practice if we need to add meter data to the model? Would it be to create a relationship class and connect the Low Voltage Service features with a standalone table with the meters data? Or, create a new asset group/asset type for meter? And, what would be the best option if we want to implement an Outage Management System (OMS) using this model as a foundation?
Remember, the Electric Foundation model is just your first step. Based upon your question you can either modify the service point properties to include meter fields that are already available in the device layer, or you can add another LV Meter Asset type (don't forget your rules) and add appropriate fields already in the device layer.