Megger is a term closely associated with electrical testing and measurement equipment, particularly known for insulation resistance testers (also called megohmmeters or "meggers").

Meggar

• Purpose: An electrical megger, or insulation resistance tester, is a specialized instrument used to measure the electrical resistance of insulation in various electrical components and systems. This includes wires, cables, motors, generators, transformers, and electrical installations.
• Function: It works by applying a high DC voltage (ranging from a few hundred volts to several kilovolts, depending on the application and the tester) across the insulation being tested. The instrument then measures the small leakage current that flows through the insulation. Using Ohm's Law ($R=V/I$), it calculates and displays the insulation resistance value, typically in megohms (MΩ) or even higher units.
• Importance: Testing insulation resistance with a megger is crucial for:
  • Safety: Identifying deteriorated insulation that could lead to electric shock or fire hazards.
  • Reliability: Assessing the condition of electrical equipment and predicting potential failures.
  • Maintenance: Performing preventative maintenance to avoid costly breakdowns.
  • Quality Assurance: Verifying the integrity of insulation during manufacturing and installation.
• Key Features: Electrical meggers often have:
  • Multiple test voltages: To assess insulation under different stress levels.
  • High resistance measurement range: To accurately measure the typically high resistance of good insulation.
  • Analog or digital displays: To show the resistance value.

When you hear "electrical megger," think of the tool used to check the health and integrity of the electrical insulation that protects us and our equipment from dangerous electrical faults.