What are Parasitic Loads?

          Parasitic loads are electric devices and appliances which draw power even when they are off.  For example, the television which has been switched off using the remote but, is still connected to the power socket continues to draw a small quantity of power.  Parasitic loads are other known as phantom loads or
vampire loads.

          It is estimated that around 5% to 10% of the total load consists of phantom loads.  Phantom loads can be avoided by disconnecting any device not in use from the mains supply.

           For example, a kitchen mixer should be disconnected from the mains or the switch of the power socket switched off when the device is not in use.  Another example would be a laptop that is switched off with a power adaptor which is still connected to the mains. 

What causes Parasitic loading

          Devices which have windings, such as motors, transformers draw a charging current.  The charging current is constant throughout the loading cycle of the machine.  The charging current causes Iron losses due to eddy current heating.  This power is wasted as heat and hence is a loss to the power system.   

          Many countries such as the US, Britain, and the EU have initiated laws which stipulate that appliances in the switched off mode should not draw power more than 1 watt.  This is known as the One Watt Initiative.  Better design of transformer with Torroidal cores which generate lesser losses is one way of reducing phantom power.