the reality is that telkoms lines are not properly protected and that is where the real damage comes in.
Most damage is incoming on AC mains. Surges are electricity. AC mains are the most often struck. Surge is electricity flowing from a cloud to earthborne charges. Most common destructive path is incoming on AC mains, through a computer modem or portable phone base station. Then to earth via phone lines. First that current flows through everything. Much later, only something (the weakest link) fails. Most modem, portable phone base stations, fax machines, etc are damaged because current is incoming on AC mains and outgoing on phone line. Both paths must exist to have damage.
Every incoming wire inside every cable must connect to single point earth ground BEFORE entering a building. Any one wire violating that requirement means the entire surge protection 'system' is compromised. Both phone wires must connect to earth via a 'whole house' protector. Every AC electric wire must also connect short to earth either directly (ie neutral) or via a 'whole house' protector.
And every connection must be short to the same earthing electrode. A separate paragraph because wire length (and other similar factors) is so critical.
For example, AC electric enters on one side of a building. A satellite dish enters and is earthed on the other side. Then satellite equipment may be damaged by a surge incoming on AC mains. Surge incoming on AC mains found earth ground destructively via the satellite dish. Again, the both incoming and outgoing path defined.
Do not make an assumption that a majority make. For example, let's assume a surge enters a computer via AC mains; outgoing via modem and phone line. That same surge is also incoming to computer memory. But memory has no outgoing path. Therefore memory cannot be surge damaged no matter how massive that surge. No 'incoming and outgoing paths' means no surge damage.
That incoming and outgoing path is also why a building earth ground must be 'single point'. Surge do not crash on a satellite dish transponder, destroy electronics, then stop. It is electricity. First current is flowing through everything simultaneously in a path from cloud to earth. Long later, something in that path fails - ie the transponder.
Yes, phone lines also require a 'whole house' protector. Something that costs so little as to be installed for free everywhere in North America. In other nations, buy and earth one. But again, the protector is only as effective as its earth ground.
The effective 'whole house' protector costs about $1 per protected appliance. Compare that to ineffective plug-in protectors that cost typically 20 and 100 times more money per appliance. And that do not even claim to provide surge protection. Why do telecoms install a superior 'whole house' protector? Because it also costs significantly less.
Routine is to have direct lightning strikes without damage. What determines whether that can happen? Earth ground. More expensive protectors do nothing to improve protection. Every protector is only as effective as its earth ground. What makes that protector even better? Better earthing. No magic box is protection which is why even the tiniest protector can provide the best protection. It is only as effective as the earth ground it connects to.
Disconnecting is one of the least reliable solutions alongside plug-in protectors. Disconnecting is dependent on one of the least reliable solutions - humans. Effective protectors are always there so that even direct lightning strikes cause no damage. But again, that is true only if humans properly earth every incoming wire.
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