The main differences between common mode protection and differential mode protection of lightning arresters are as follows:

1： The protected objects are different.

Common mode protection: mainly aimed at protecting against common mode overvoltage between the line and the ground, aiming to prevent damage to equipment caused by excessive voltage between the line and the ground due to external lightning strikes or other electromagnetic interference, and to protect the insulation of equipment and personnel safety.

Differential mode protection: focuses on protecting the differential mode overvoltage between two wires in the circuit, preventing the instantaneous high voltage difference between the two wires from damaging the electronic components inside the equipment, such as integrated circuits, chips, etc.

2： The types of interference signals are different.

Common mode protection: mainly suppresses common mode interference signals, which are usually induced by external electromagnetic fields on the transmission line. Its characteristic is that they appear simultaneously on all wires of the transmission line, with the same size and direction.

Differential mode protection: For differential mode interference signals, differential mode interference refers to interference signals with equal amplitude and opposite direction that appear on two wires of a transmission line. It is mainly caused by internal factors such as changes in the load in the line and fluctuations in the signal source.