Selection of megohmmeter: What size megohmmeter is suitable to buy?
When selecting the size of the megger, it needs to be determined based on the voltage rating of the electrical equipment.
If an electrician is engaged in low-voltage operation, he or she usually chooses a megohmmeter of 250V-500V. If an electrician is engaged in high-voltage operation, he or she can choose a megohmmeter of 1000V-5000V.
When measuring 250V electrical equipment, you can use a 1000V or 5000V megohmmeter to measure its insulation resistance value, which is likely to be broken down. Explanation: The original resistance value is qualified.
Therefore, when choosing a megohmmeter, you need to determine the range of the megohmmeter according to the voltage resistance level of the electrical appliance under test. Choose a 500 megohmmeter for voltages below 500V, and a 1000-2500 megohmmeter for voltages above 500V.
Megohmmeter selection requirements:
Choose a megohmmeter based on the object to be measured and the rated working voltage. Megohmmeters are classified according to output voltage. Commonly used specifications include 250V, 500V, 1000V, 2500V, 5000V and other models.
When the working voltage of the object being measured is low, you can choose a 250V megohmmeter. Most of the AC power supply in my country is three-phase 380V (single-phase 220V), and a 500V megger is generally used. This is also a necessary measuring instrument for electricians and home appliance maintenance personnel. 1000V, 2500V, and 5000V are mainly used on electrical equipment lines with higher working voltages and are used by electrical testing professionals.
The initial reading of some megohmmeters is not zero, but 1MΩ or 2MΩ. If this type of megohmmeter is used to measure electrical equipment, household appliances or circuits in a humid environment, it may cause a misreading of zero megohms. Judgment.
Therefore, when general electricians and home appliance maintenance personnel choose a megohmmeter, they should choose a megohmmeter with a measuring range of 0~200MΩ or 0~500MΩ.
