After my router broke in a thunderstrorm, I am trying to establish surge protection for power lines as well as (this question) for telephone/internet lines.
I found devices such as Tupavco TP302, using gas discharge tubes. It is placed between the TAE wall data outlet and the router. In contrast to others, it has also a grounding cable. I thought a grounding cable would offer additional security to get rid of surges, but...
- Is this truly beneficial? Isn't it enough to shortcircuit the 2 wires with the potential difference? Or is it simply "faster" for the current to escape via a (thicker) grounding cable? (The attached grounding cable is quite thin, I'd say less than the standard 1,5 mm for AC wiring :-(
- Could it be even a disadvantage? What about surges that might possibly enter via ground, especially if the telecommunication line is not connected to the "same" ground (main grounding terminal). Could temporary transients (as explained here) between the main grounding terminal of the house ("Potentialausgleichsschiene", AC power for router) and telecommunication ground (data lines) after an (indirect) flash of lightening rather cause destruction?
- Would ignoring the grounding wire of the data surge protector (i.e. not attaching it to ground) result in a disadvantage compared to a device that simply does not have a grounding cable in the first place? (I assume the grounding cable simply the center tap of the gas discharge tube(s)?)
- Most important: Would it be safe to connect the grounding cable of the data surge protector to AC power ground (PE contact, e.g. via a plug where I connect only the grounding (PE ) wire?)** I am hesitating to touch AC power outlets/plugs. Commercial grounding plugs I found so far have 1 MOhm resitance (necessary for EMD protection while touching electronics), thus not suitable. Alternatively I thought of iron water/heating tubes, but would have to determine resistance/impedance to earth and possibly introduce a "third" ground potential. Better than nothing?
AC power network is most likely TN-C in Germany as far as I found out so far.
I found the following schematic drawing (Tupavco website) of a rack-mountable version of the device (I can only guess it uses the same technique as my not-rack-mounted device), showing GDT betweeen paired lines, with the center tap connected to ground: