Smart Grids are modern versions of the existing grids with an add-on intelligence for an cost-effective and green electric grid network. It amalgamates Information and Communication Technologies in different domains of power grids namely generation, transmission, distribution and consumption by incorporating full-duplex communications till the last-mile node in the distribution networks. SGNs are composed of network areas namely Home, Neighborhood and Wide Area Networks defining its architectural boundaries for communication. NAN is composed regional networks having number of HANs and is enable to provide distributed automation. NANs form the major actors in the Distribution domains. Recently developed standard IEEE 802.15.4g (a PHY and MAC amendment to 802.15.4) will be suitable for large scale deployment of low-data-rate wireless networks, specifically the smart metering utility networks. Smart Utility Networks (SUN) PHY are provided with a wide range of frequencies ranging from 450 MHz to 2.4 GHz in different operating modes. This will provide Smart Grids with unmatched features.