Understanding AC Current and Mains Electricity
Alternating current (AC) is what powers your home, and it's quite different from the direct current in batteries. Unlike direct current that flows in one direction only, AC repeatedly reverses its direction of flow throughout each cycle.
Your mains circuit has two main wires: a live wire that's alternately positive and negative each cycle, and a neutral wire that stays at zero volts. The peak potential difference is simply the maximum voltage measured from zero - this is the highest point the voltage reaches during each cycle.
When it comes to cables and plugs, safety is everything. Socket and plug cases are made of stiff plastic materials because plastic is an excellent insulator that protects you from electrical connections. A mains cable contains 2 or 3 insulated copper wires surrounded by flexible plastic.
Key Safety Tip: The earth wire connects to the longest pin and earths the metal case of appliances - if too much current passes through a fuse, it melts and cuts off the power, protecting you and your devices.
