On Monday, October 26, 2015 at 7:04:19 PM UTC-4, Muggles wrote:
I do understand what you've been saying about earthing. The current has
to have an entry and exit point as it's searching for it's target.

Surges that do damage are hunting for earth ground. A lightning strike is a direct connection from cloud to earthborne charges maybe 5 miles distant. A shortest electrical connection may be three miles down to earth and four miles through earth to those charges. If appliances get in that path, then damage occurs.

A direct strike to AC wires far down the street is incoming to every household appliance. Now that current must hunt for an outgoing path to earth via some appliances (and to charges maybe four miles away). If that current is connected to earth BEFORE entering a structure, then no destructive hunt exists inside the house.

Best protection for TV cable is a hardwire from cable to single point earth ground. Then a surge need not enter on TV cable.

AC electric and phone cannot connect directly to earth. So a 'whole house' protector does what that hardwire does better - connect a surge to earth.

If every wire inside every incoming cable makes a low impedance (ie less than 10 foot) connection to earth, then an incoming and outgoing path (the hunt) need not exist via appliances.

A protector is only a connecting device to what does protection. Protection is a connection to and quality of earthing electrodes at the service entrance. Every effort to improve earthing and lower impedance (ie shorten that hardwire) increases appliance protection. Then a surge is less likely to blow through protection inside appliances. A surge is less likely to find earth destructive via appliances.

Earthing is how protection was done over 100 years ago. And how it is done in every facility that cannot have damage. Protectors are only connecting devices to what really does protection - single point earth ground.