Understanding The Electricity Grid Distribution. The national grid is supplied with three phase from a substation to a transformer through high tension power lines in three or single phase. The transformer steps down that power from 11kV to 415v for three phase low voltage lines or to 240v single phase low voltage power line. #electrician #electrical #electricity #viralreels #reelsfb #trendingreels #instadaily | Topheights Electricals and Electricians