Lightning and your modem

[westom]

I leave everything on...but plugged into one of those surge protector plugs/strips. Just lost a modem about a month ago, but it was a weird one. Seems like one of my WiFi router LAN ports blew also (The one connected to the modem at the time).

As another so accurately noted, nothing stops a surge. Not mentioned are so many facilities that suffer direct lightning strikes without damage. What they do not use is a protector too close to electronics and so far from earth ground.

Surge is energy hunting for earth. Either you earth that energy harmlessly outside the building. Or nothing stops that energy from hunting for and selecting a destructive path to earth via some appliance.

What does a protector adjacent to an appliance sometimes do? Gives that surge even more paths to find earth - destructively. Such as through an adjacent modem.

No surge protector does protection. Either a protector connects hundreds of thousands of joules harmlessly to earth. Or it is a profit center. Where is a dedicated wire for the always required short (ie 'less than 3 meter') connection to single point earth ground?
That wire is how hundreds of thousands of joules are connected - harmlessly. How many joules in that plug-in protector? Hundreds? How does that protector without a short connection to earth make hundreds of thosuands of joules disappear? It doesn't as modem damage also demonstrates.

 

[Nokkie]

So basically these surge plugs are just another gimmick? Or do they actually serve a function?

As another so accurately noted, nothing stops a surge. Not mentioned are so many facilities that suffer direct lightning strikes without damage. What they do not use is a protector too close to electronics and so far from earth ground.

Surge is energy hunting for earth. Either you earth that energy harmlessly outside the building. Or nothing stops that energy from hunting for and selecting a destructive path to earth via some appliance.

What does a protector adjacent to an appliance sometimes do? Gives that surge even more paths to find earth - destructively. Such as through an adjacent modem.

No surge protector does protection. Either a protector connects hundreds of thousands of joules harmlessly to earth. Or it is a profit center. Where is a dedicated wire for the always required short (ie 'less than 3 meter') connection to single point earth ground?
That wire is how hundreds of thousands of joules are connected - harmlessly. How many joules in that plug-in protector? Hundreds? How does that protector without a short connection to earth make hundreds of thosuands of joules disappear? It doesn't as modem damage also demonstrates.

 

[westom]

So basically these surge plugs are just another gimmick? Or do they actually serve a function?

First learn what a protector does. An excellent summary from Dr Schneider:
> Conceptually, lightning protection devices are switches to ground. Once a threatening surge
> is detected, a lightning protection device grounds the incoming signal connection point of the
> equipment being protected. Thus, redirecting the threatening surge on a path-of-least
> resistance (impedance) to ground where it is absorbed.
> Any lightning protection device must be composed of two "subsystems," a switch which is
> essentially some type of switching circuitry and a good ground connection-to allow dissipation
> of the surge energy.

Does your telco disconnect phone service all over town when a storm approaches? Their overhead wires connected to every building in town means typically 100 surges with each storm. Why no damage? Telcos all over the world connect each wire inside every incoming cable as short as possible to earth ground. Why? See Dr Schneider’s summary. Either hundreds of thousands of joules dissipate harmlessly in earth. Or the protector does not even claim that protection.

How to identify ineffective protectors. 1) No short and dedicated wire to single point earth ground. 2) Manufacturer will not even discuss earthing.

Well proven from over 100 years of experience. How to make every protector even better? Upgrade single point ground. Make that connection even shorter (ie no sharp wire bends, not inside metallic conduit, etc). Every facility that cannot have damage always connects every incoming wire to earth ground. Either directly (cable TV, satellite dish). Or via a 'whole house' protector (telephone, AC electric). The simple conclusion: A protector is only as effective as its earth ground.

 

[Nokkie]

Thanks, are there any types of earth grounds available? (type class).

Do you know what a normal house hold would use?

 

[westom]

Thanks, are there any types of earth grounds available? (type class).

Concepts are demonstrated in this application note. Shown are two structures. Each must have its own single point ground. In this picture, each single point ground is a buried loop. A lesser but still required earth ground is every utility cable enters at one point. Connected short to a network of earth ground rods (3 meters or longer). And every wire in every cable connected to that earth ground before entering:
http://www.erico.com/public/library/fep/technotes/tncr002.pdf

Even underground cables must be earthed before entering.

Any wire between those two structures must be earthed when entering each structure. Replace the antenna tower with a second building. What happens when lightning strikes that building? It can connect that surge to earth ground via electronics in the first building. Just another reason why all incoming cables for both buildings must be earthed.

Some of these concepts were pioneered in munitions dumps where surges must never cause damage. Ufer ground - rebar inside an electrically conductive material such as concrete - is a superior earth ground. Or why surge protection is installed when the footings are poured.

The concept is simple. Some surge protection 'systems' have no protectors. But in every case, protection is about earth ground (not safety ground, chassis ground, motherboard ground, receptacle ground, etc). Either that energy dissipates harmlessly outside the building. Or energy goes hunting for earth destructively via appliances. No protector stops that hunt. Routine is to earth a 'whole house' protector at the service entrance - where all utility wires must enter. And upgrade the only thing that does protection - single point earth ground.

Protection is always about where energy dissipates. Any discussion that does not discuss energy dissipations - assume the worst. A protector is only as effective as its earth ground.

 

[Nokkie]

thx for the explanation