Megger testing is a method used to measure the insulation resistance of electrical systems and equipment. It involves using a device called a megohmmeter, which applies a high voltage to the insulation and measures the resistance. This helps identify any potential faults or degradation in the insulation that could lead to electrical failures or hazards. The test is commonly performed on various electrical components, including cables, motors, and transformers. By ensuring that insulation is intact, megger testing plays a crucial role in maintaining safety and reliability in electrical installations, preventing accidents and equipment damage.