A typically destructive surge seeks earth ground. For example, a surge is a connection from clouds to earthborne charges some miles distant. A lightning strike to wires on the street may find earth via your AC mains service, household appliances, to earth. That is called surge damage. That is they type of surge that overwhelms protection inside appliances.
All appliances contain surge protection which makes most every surge irrelevant. But the rare and typically destructive surge overwhelms internal protection. Will some surge protector stop what three miles of sky could not? Retail stores will say that. Will that silly few hundred joules absorb surges of hundreds of thousands of joules? Of course not.
A surge that does not enter the building does not find earth destructively via appliances. That is how surge protection was installed even 100 years ago. Either massive energy is dissipated harmlessly in earth. Or that energy enters a building, destructively hunting for other paths to earth. Your choice.
Do you stop or absorb what even three miles of sky could not? Of course not. So how does your telco, with computers connected to overhead wires all over town, have no surge damage? Is telephone service down for four days all over town while they replace that computer? Of course not. Telcos use the same 100 year old concept. Every wire in every cable connects short to earth before entering the CO.
A protector is not protection. Protection is what a protector connects to. Earth ground dissipated all that energy. A protector either makes a low impedance connection to earth OR the protector must somehow stop that surge. Telcos do not use plug-in protectors for one simple reason. All but no earth ground. AND it does not even claim to provide that protection.
Telco also installs a ‘whole house’ protection on every subscriber’s interface – the NID box. But again, that protector is only as effective as what will absorb direct lightning strikes. That means a ground wire from the NID must be short (ie ‘less than 10 feet’), no sharp wire bends, separated from all other non-grounding wires, not inside metallic conduit, no splices, etc. Each requirement simple but critical for a low impedance (not low resistance) connection to earth.
Why is an AC wall receptacle safety ground not earth ground? See those requirements for low impedance? Safety ground wire violates virtually every requirement for effective earthing.
A protector is only as effective as its earth ground. IOW each protection layer is defined by one thing – a single point ground. No matter how many protectors are installed; if all connect to the same earthing electrode, then only one protection layer exists. That which absorbs surge energy defines the layer.
Single point earth ground is the same principle that makes your telco’s CO protection so effective. Cable TV wire also must drop down to also make that short (ie ‘less than 10 foot’) connection to earth – before entering the building. Cable TV and satellite dish are connected directly to earth. No protector required.
Telephone and AC electric require a protector to connect to earth. Telco provides one for free because that protector is so inexpensive and so effective. Any protector without earthing (ie on a UPS) would do nothing except degrade phone service (especially DSL). But a source of most destructive surges is AC mains. Wires highest on utility poles (most often struck) make a direct (destructive) connection to all household appliances. Worse, most all homes have no ‘whole house’ protector – have all but no surge protection.
What is typical modem damage? Incoming on AC mains. Through computer and modem. Out to earth ground via a phone line. First a surge current flows in everything in a path from cloud to earth. Then something in that path fails. Typically destroyed part was a PNP transistor that drives an off-hook relay. It suggests the amount of experience and technical knowledge behind this post. Many lightning damaged modems were repaired, and still working even 10+ years later. We followed the surge path, then fixed damaged parts. In every case, the damaged part was in a path from cloud to earth.
Earth a ‘whole house’ protector from one of many responsible companies such as General Electric, Square D, Intermatic, Leviton, Keison, Siemens, etc. A Cutler-Hammer ‘whole house’ protector sells in Lowes for less than $50. That will connect an incoming surge to earth. Quality of and connection to earth determines protection. Earthing must be upgraded to both meet and exceed post 1990 National Electrical Code requirements. One indication that your home may be earthed for human safety but not sufficiently for surge protection.
A breaker box ‘whole house’ protector would be earthed by a bare copper 6 AWG (quarter inch) wire from breaker box to an earth ground rod. If that wire travels up over the foundation and down to earth, then higher impedance is created. That wire must go through the foundation and down to earth. To make it shorter, to eliminate sharp wire bends, to separate it from other wires, etc.
Lower impedance is how to make a connection to earth – shorter, no sharp bends, etc. High impedance is why plug-in protectors have all but no earth ground. Why plug-in protectors must stop what three miles of sky could not. Why any facility that must never suffer surge damage does not use power strip and UPS protectors. Why protection means being fanatical about earthing.
Above only discussed secondary protection. What defines each protection layer? The one thing that every layer must have – earth ground. Home owners should also inspect their primary protection system:
http://www.tvtower.com/fpl.html View manufacturer numeric specs for that plug-in protector. Show us the numbers that list each type of surge and protection from that surge. Noted earlier: all appliances contain surge protection. Any protection provided by that power strip protector (and near zero protection provided by a UPS) is made irrelevant by protection inside appliances. Notice, no manufacturer specs claim that protection.
How to identify ineffective protectors: 1) It has no dedicated wire for that always essential ‘less than 10 foot’ connection to earth. 2) Manufacture even avoids all discussion about earthing. That defines most every power strip and plug-in UPS.
And finally, is a more expensive protector better? Do you view the price or learn the science? Science is what Ben Franklin demonstrated in 1752. Meanwhile, a $7 grocery store protector has the same circuit found in a $150 protector sold in Best Buy. Monster Cable (same company that sells speaker wire with polarity for maybe $70) locates obscenely profitable markets. Most expensive protector comes from a company with a long reputation selling scams? That is what some have claimed.
Do you spend $150 for each appliance including dishwasher, clock radio, and bathroom GFCIs? When damage is never an option, a ‘whole house’ protector is installed for about $1 per protected appliance. Price does not define quality – once we learn how these things really work. Spend tens or 100 times less money for protection that actually works. Do hundreds of joules stop surges that are hundreds of thousands of joules? Does a power strip or UPS stop what three miles of sky could not? Retail salesmen make that claim. But then appreciate their profit margins. A $7 solution selling for as much as $150 because it has fancier paint.
The informed consumer buys a solution well proven for over 100 years. That is required by the US Air Force. That is defined by the Sun Microsystems guide for server installations. That has been routine so that munitions dumps suffer direct lightning strikes without explosions. Spend less money for the well proven and superior solution. Then upgrade what provides protection: earth ground. A protector is only as effective as its earth ground.
