Originally Posted by
westom
The first mistake is to assume a millimeters gap in an RCD will block what three kilometers of sky cannot. Or that an RCD, that takes milliseconds or longer to trip, will somehow 'block' a transient done in microseconds.
Only urban myths 'block' or 'absorb' that energy from a surge. And yet that is exactly what a Belkin or equivalent magic boxes must do. How does its 600 joules 'absorb' a surge that can be hundreds of thousands of joules?
Second, wall receptacle safety ground is completely different from many other, electrically different grounds (logic ground, floating ground, analog ground, ground plane on an antenna, virtual ground, ground beneath shoes that is relevant for static electricity, chassis ground, power ground, or earth ground). Only relevant ground is earth ground. It must be 'single point earth ground', as another may have noted. (All four words have electrical significance.)
Relevant concept was demonstrated by Franklin over 250 years ago. Lightning connected to distant earthborne charges destructively via something more conductive - wooden church steeple. But that steeple is not very conductive. So steeple damaged.
Franklin simply connected direct lightning strikes to earth via something very conductive. So lightning no longer connected to distant charges (maybe four kilometers away) destructively via a steeple.
Lightning connect to distant earthborne charges destructively via appliances. But appliances are not sufficiently conductive. So appliances (ie satellite dish electronics) damaged.
Solution implemented the world over, even 100 years ago, connected lightning to distant earthborne charges via a 'whole house' protector that connects low impedance (ie less than 3 meters) to earth. So lightning no longer connected to distant charges (maybe four kilometers away) destructively via any household appliance (including dish electronics).
Third, an AC utility demonstrates how to avert damage. View good, bad, and ugly (preferred, wrong, and right) installations at:
then select Tech Tip 8.
Protection is always about how that electric current connects from the cloud (maybe three kilometers up) to earthborne charges (maybe 4 kilometers through earth). Protection means that path is not anywhere inside. That means every wire inside every incoming cable must make a low impedance (ie less than 3 meter) connection to the same earth ground. Not wall receptacle safety ground or any other ground. It must be those earthing electrodes.
If any other earth ground is used, then all protection is compromised.
Four, these techniques are well understood. Each dish is treated as if separate structures. So each dish must have its own single point earth ground. Its coax cable must connect directly (low impedance) to that earth ground.
At the other end of each cable must be a low impedance (ie hardwire has no sharp bends) connection to the building's earth ground. That connection made BEFORE that coax cable enters.
Well, that best protection (that uses no protector) means a surge is not incoming on any dish. But most surges are incoming on AC mains. A direct lightning strike to AC wires many blocks down the street is a direct strike incoming to every appliance. Are all damaged? Of course not. This is electricity. So it must also have a completely different outgoing path to earth ground. Only some appliances might make a destructive outgoing connection.
Incoming on AC mains. Outgoing destructively to earth via the sat decoder and properly earthed coax cables. Once a surge is all but invited inside by any wire, then it will go hunting for earth ground destructively via any appliances.
Protection means every wire (all AC wires) also must connect to that same earth ground. Safety codes only define one AC wire connected to earth. Surge protection means all wires must connect to earth. So all over the world, that connection is made by a 'whole house' protector.
Again, that connection must be low impedance. A protector must make a less than 3 meter connection from each AC wire to single point ground. That connection must have no sharp bends or splices, not be inside metallic conduit, must be separated from other non-grounding wire, and must as short as possible. Connector length is more critical than connector diameter.
Obviously most of this was unknown by most others. And yet this technology has been standard in all Telstra facilities for longer than any of us have existed.
Again, no plug-in box does or even claims to provide effective protection. The effective protectors come from other manufacturers who a have earned a reputation for integrity (Belkin has not). Such as Clipsal, ABB, Siemens, and Novaris to name but a few.
Five, lightning is typically 20,000 amps. (Static electricity is microamps - irrelelvant.) So a minimal 'whole house' protector is 50,000 amps. Because protectors must remain functional for many decades after multiple direct lightning strikes. These effective products will probably cost about $1 per protected appliance - tens of times less than Belkin.
An effective solution will always answer this question. Where do hundreds of thousands of joules harmlessly dissipate? That hardwire connection from coax to earth ground or that low impedance connection from AC mains to earth ground - both are answers to that question. Belkin's answer: a paltry 600 joules. Ineffective protection. And another device that must be protected by the 'whole house' solution.
Finally, best evidence is found in each damaged electronics. Damage defines incoming and outgoing paths. Damage is most often on the outgoing path. How does that cloud connect to earth and earthborne charges some 4 km distant? Damage only happens when the path is anywhere inside a building. Nothing inside a building even claims to protect from such transients. Damage is always averted when that transient current connects to earth BEFORE entering a building.
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