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What is the difference between Class 10 and class 20 Overload Relays For Thermal overload relays ?

- For all types of thermal overload relays (LRD or LR9D or LR9F), These can be classified as follows:
* Class 10: According to IEC60947-4-1, it specifies the tripping time for 7.2 In to be between 2 to 10 Seconds
* Class 20: According to IEC60947-4-1, it specifies the tripping time for 7.2 In to be between 6 to 20 Seconds

This difference in tripping time has value in time coordination,