Every complete circuit must include a "load'' (something to use the electricity coming from the source). Without this load, the battery would attempt to deliver its entire power supply from one pole to another. The electricity would take a short cut to ground and cause a great amount of damage to other components in the circuit by developing a tremendous amount of heat. This condition could develop sufficient heat to melt the insulation on all the surrounding wires and reduce a multiple wire cable to a lump of plastic and copper.