An effective protector means a direct lightning strike does not even damage the protector. Appreciate the many myths stated and implied in so many posts. If you think that article was long, appreciate how many myths here need be exposed.
The principle: Lightning seeks earth ground. A better path to earth is via something more conductive - wooden church steeple. But since wood is not an ideal conductor, then current through that wood creates a voltage. Science: 20,000 amps times a large voltage is large and destructive energy. Church steeple damaged due to that massive energy.
Franklin installed a lightning rod connected to earth. Lightning obtains earth ground via the rod and ground wire. Wire is conductive meaning near zero voltage. 20,000 amps times near zero voltage means near zero energy. No damage.
Did a lightning rod protect that church? Of course not. That rod and wire are only connecting devices. Energy was harmlessly dissipated in the protection device - earth ground. The simple principle when a direct lightning strike causes no damage. Well proven even 100 years ago.
Lightning strikes AC wires down the street. The path to earth ground means that lightning strikes your appliances directly. Appliances damaged because AC electric wires act like antennas; connect lightning to earth destructively via appliances. The solution: do what Franklin demonstrated. Do what has been the only effective solution for over 100 years.
Every wire in every cable must connect to earth ground before entering the building. If lightning connects to earth before entering, then where does energy dissipate? Earth ground - not inside a protector - is the protection. Surge protection is always about where energy dissipates. Always. Single point earthing is so critically important.
Will a plug-in protector rated for a few hundred joules absorb surges that are hundreds of thousands of joules? Of course not. No plug-in protector claims such protection in its numeric specs. They are not sellig protection. Only facts that matter are numbers in the manufacturer's specifications. No plug-in protector claims effective protection.
A few hundred joules in a protector will absorb hundreds of thousands of joules? Many will promote that myth by ignoring numbers. How does it stop what 3 kilometers of sky could not stop? See those spec numbers. No plug-in protector (or UPS) claims effective surge protection.
It claims to protect from a type of surge that is not typically destructive. That means it can claim surge protection, in big letters, on every box and sales brochure. Then sell a $3 power strip with some ten cent parts even for $150. A profit center; not surge protection. And a majority will recommend it - especially if a surge damages its undersized components.
As demonstrated up top: effective protection means energy harmlessly absorbed in earth. So we connect every incoming wire short to a common earthing electrode. Cable TV and satellite dish wires connect ‘less than 3 meters’ without any protector. A ground box and some wire means massive surge protection. AC electric and telephone wires cannot connect directly. So we install a ‘whole house’ protector to make that connection to earth. A surge dissipated harmlessly in earth does not hunt for ground inside the building. Does not find ground destructively via household appliances.
Your telco’s computer is connected to telephones all over town via overhead wires. It suffers about 100 surges with each thunderstorm. How many times has your town been without phone service for four days while they replace that computer? Telcos waste no money on ineffective plug-in protectors. Telcos spend tens of times less money for the protector that earths a direct lightning strike – and remains functional. That is the ‘whole house’ protector. Each protector is located where a wire enters the building. And connects as short as possible to the earth ground used by every protector – single point earth ground. To make that protector even better, you telco also increases separation between the protector and electronics. Up to 50 meter separation between protector and electronics means even better surge protection.
Those are the principles. Principles explain why plug-in protectors (or UPSes) do not even claim effective protection. You must install a single point earth ground. A protector is only as effective as its earth ground. How to make protectors even better? Make that ground connection shorter, no sharp wire bends, and ground wire not inside metallic conduit. Then increase the earth ground. Best protection means a ground wire completely surrounding a building, or installed when foundation footings are first poured. A best earth ground is inside something conductive – concrete.
Coax cables (ie cable TV) need no protector. Better protection is only a wire from that cable to earth ground. One ‘whole house’ protector for the phone line. Another for AC electric. Do what Ben Franklin demonstrated in 1752. And that is how surge protection has been installed for over 100 years. Technology is that well proven. Is used even in munitions dumps so that direct lightning strikes do not cause explosions.
Surge protection is always about where energy dissipates. Any recommendation that ignores ‘where energy dissipates’ is promoting a scam. Why do plug-in protectors not make protection claims in numeric specs? No dedicated and short connection to earth. No earth ground means no effective protection. A protector is only as effective as its earth ground.
