The gas discharge tubes are designed to withstand many impulses without destruction or loss of the initial characteristics (typical impulse tests are 10 times x 5kA impulses for each polarity).
On the other hand, a sustained very high current, i.e. 10A rms for 15 seconds, with simulate the dropping out of the AC power line onto a telecommunication line and will take the GDT immediately out of service.
If a fail-safe end of life is desired, i.e. short circuit that will report a fault to the end user when the line fault is detected, the gas discharge tube with the fail-safe feature (external short-circuit) should be selected.
Post time: Aug-08-2018