What feature defines the effectiveness of a transmission arrestor?

The effectiveness of a transmission arrestor is primarily determined by its voltage rating. This rating indicates the maximum voltage at which the arrestor can operate safely without failure. A properly rated arrestor will effectively protect electrical equipment by shunting excessive voltages (such as those caused by lightning strikes or switching surges) to the ground, thereby preventing damage to the system.

The voltage rating is crucial as it ensures that the arrestor operates within safe parameters and can effectively handle surge events. If the voltage rating is too low for the application, the arrestor may not engage during a surge, leading to potential damage. Therefore, a correct voltage rating is essential for the reliability and performance of a transmission arrestor in protecting electrical infrastructure.