Today, Internet of Things is an important topic in Research. One key technology for IoT development is PLC (Power Line Communications), which is widely used in Domotic Networks. Although PLC for low voltage networks have been studied widely in physical layer aspects, one important theorical lack of this studies is the abscence of traffic models for these networks. Then, there are no models that allows dimentioning in such scenarios. With the aim to improve this situation, we have performed a study with a Narrow Band PLC Low Voltage Network. In this work, we have performed traffic measurements, and we obtained that this system can be modeled as a Poisson traffic model, which allows PLC networks dimentioning in a simple way.