What is the difference between Megger and Hipot?
The difference between Megger Test and Hi-Pot Test are widely used in
- Motors,
- Transformers,
- Cables and
- Switchgear testing.
Difference between Megger Test and Hi-Pot Test
| Parameter | Megger Test | Hi-Pot Test |
|---|---|---|
| (Insulation Resistance Test) | (High Potential Test) | |
| Purpose | Used to measures insulation resistance value | Used to tests insulation strength and breakdown capability |
| Main Function | Helps to detects insulation deterioration, moisture, and leakage | Used to verifies insulation can withstand high voltage stress |
| Test Voltage Type | DC Voltage | AC or DC Voltage |
| Voltage Level | Low to Medium (250V to 10kV typical) | Very High Voltage (2kV to 100kV depending on equipment) |
| Measurement | Provides resistance value in Megaohms (MΩ or GΩ) | Provides leakage current value in mA or µA |
| Test Nature | Non-destructive test | Potentially destructive test if insulation is weak |
| Risk to Equipment | Safe for the routine maintenance | Can damage the insulation if weak (or) defective |
| Usage Frequency | Routine maintenance test | Commissioning or periodic certification test |
| Detects | Moisture, contamination & insulation aging | Insulation breakdown & dielectric strength |
| Output Result | Insulation Resistance value (e.g., 500 MΩ) | Pass (or) Fail based on leakage current |
| Equipment Used | Megger (Insulation Resistance Tester) | Hi-Pot Tester |
| Test Duration | Short (usually 1 minute) | Longer (1–10 minutes typical) |
| Application Stage | Preventive maintenance | Factory testing, commissioning, and safety certification |
| Safety Level | Lower risk compared to Hi-Pot | Higher risk due to high voltage |
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