Westom, I don't know how it happened but it did. I did not imply that the electricity magically traveled up a dead-end wire with no p.d acoss - that would be a dumb thing to say. ... And why would an Ethernet port be required to withstand thousands of volts without damage?
You may not have meant electricity flows through a dead end wire. But surprisingly, a majority do. These posts are for everyone - not just you. The fact that damaged ethernet ports exist says a surge current (current - not voltage) was seeking earth ground via those wires. This, for example, is how we confirmed that a plug-in protector earthed a surge destructively through a network of powered off computers.
We literally followed the path through the network wire by identifying and replacing failed semiconductors. Plug-in protectors earthed a surge from AC mains to earth ground via powered off computers - destructively. Anything that tried to stop that surge means voltage increases, as necessary, to destructively blow through. If you replaced those 2000 volt ethernet ports with 4000, then voltage will increase to 4000 volts so that current still flows.
All electronics withstand voltages without damage. One reason is static electricity. Meanwhile IEC and other international standards now require interface electronics to withstand 2000 and 15000 volts without damage. (Due to length, the citations will only be provided on request.) Electronics have long been required to be that robust. A most robust appliance in any house is the computer's power supply.
A computer grade UPS can output power so 'dirty' as to be harmful to small electric motors and power strip protectors. But a computer's power supply, like ethernet ports and so many other interfaces, has always been so robust as to make 'dirty' UPS power irrelevant.
Why did that plug-in protector earth a surge through those networked computer? Being too far from earth ground and too close to electronics, that power strip protector bypassed internal computer protection - made damage easier - bypassed power supplies. Significant protection exists. But protection routinely inside every computer can be overwhelmed or bypassed.
Does not matter if one AC electric wire is earthed. Surge protection means every wire in every cable must be earthed. Many do not understand that to claim their AC is earthed. Obviously all incoming electric wires directly earthed means no electric service. That is why a protector is installed. An effective protector does not stop, block, or absorb surges. Nothing can do that. The effective protector earths those other AC electric wires. Every wire (include coax cable and telephone) must be earthed.
A protector is only a connecting device. Protection is earth ground. Energy must be absorbed in earth before entering a building. A plug-in protector without that short (ie 'less than 3 meter') connection to earth must earth that surge somewhere. Above example: protector earthed a surge destructively through powered off computers. Too far from earth ground. Too close to appliances.
UK has few thunderstorms typically with less energy. Why so much damage? Because most all protection is only inside appliances. Effective surge protection means energy does not enter a building - does not hunt for earth destructively via appliances. The surge that does not enter a building does not overwhelm protection already inside every appliance. BT and other facilities that must never suffer damage do not waste money on plug-in protectors or UPS. BT earths surges where wires enter the building - 'whole house' protectors. That was how it was done 100 years ago.
Not earthing every wire in every cable means you are permitting surge energy into a building. Surge damage is directly traceable to human failure. You don't see that energy inside munitions dumps. Direct lightning strikes do not cause explosions. Why? Humans installed simple solutions so that lightning is harmlessly earthed. If failure occurs anywhere, (ie in a radio station), then an analysis starts with mistakes made by humans in the earth ground 'system'.
Did telephone operators remove their headsets and leave the room when thunderstorms arrive? Of course not. Even 100 years ago, protection from direct lightning strikes has been that well understood so that operators were not killed by surges via their headsets.
Nothing stops a surge. Wooden church steeples were damaged by lightning. Why? Even wood is an electric conductor. That 20,000 amperes will flow no matter what tries to impede it. Because wood is not that conductive, then 20,000 amps times a high voltage means destructive energy dissipated in the steeple. How did Franklin eliminate damage? Nothing will stop a surge. Franklin's lightning rod simple connected (diverted, shunted, clamped, bonded) a surge to earth via a conductive path. Now 20,000 amperes times near zero voltage is near zero energy. All energy absorbed harmlessly in earth. No steeple damage. You must do same to protect your appliances. A surge that does not enter a building does not overwhelm protection that has always been inside every appliance.
A safety ground wire in every power outlet is not earth ground. Critical to surge protection is low impedance - not low resistance. High impedance is created by a wire too long, too many sharp bends, splices, inside metallic conduit, and other problems. No plug-in protector is sufficiently earthed. Worse, that ground wire is also bundled with other wires; induces surges on those other wires. To be earthed, a protector is located at the service entrance - the always critical 'less than 3 meter' connection to 'single point ground'. All protector must make a short (low impedance) connection to the same earth ground.
To make protection better, BT wants protectors up to 50 meters separated from electronics. Impedance is why a protector must be so close to earth AND why separation increases electronics protection.
