[westom]

Originally Posted by Lenhart Electric

When you are shopping for your plug-in strips, stick with a name you know, GE or Intermatic or some brand you feel will honor their warranty.

Typically, a bigger warranty means a less effective or reliable product. That applies to most all industries from cars to surge protectors.

That protector warranty is often so full of exemptions as to not be honored. But then it also does not claim to provide protection in its numeric spec sheets. Fortunately appliances already contain significant protection.

A lightning strike to overhead wires down the street is a direct lightning strike to household appliances. A surge that can overwhelm an appliance’s internal protection is the reason why a 'whole house' protector is earthed. The IEEE even defines how much protection an earthed protector provides - in numbers and from lightning. From IEEE Green Book entitled 'Static and Lightning Protection Grounding':
> Lightning cannot be prevented; it can only be intercepted or diverted to a
> path which will, if well designed and constructed, not result in damage.
> Even this means is not positive, providing only 99.5-99.9% protection. ...
> Still, a 99.5% protection level will reduce the incidence of direct strokes
> from one stroke per 30 years ... to one stroke per 6000 years ...

A protector that costs maybe $1 per protected appliance. How much for the plug-in protector costing maybe $25 or $150 per appliance? Earthing a 'whole house' protector is definitely for lightning protection of household appliances. Even the IEEE says so. Should you need additional protection, spend another $5000 for plug-in protectors to get an extra maybe 0.2% additional protection.

Above IEEE Standard 142 says protectors are installed for lightning protection. Other IEEE Standards also discuss this.

How is protection accomplished? One highly regarded source is Polyphaser’s application notes. Sorry - the system will not let me post that easily:
Triple w dot polyphaser dot com slash technical_notes dot aspx

What does your telco - their computer connected to overhead wires all over town - do to never have a surge damaged computer? Telcos don't waste money on plug-in protectors. They earth every incoming wire in every cable - for lightning protection. To make that protection even better, first, their protectors are located up to 50 meters separated from computers. That separation between protector and electronics means even better protection. Then to make protection even better, second, they upgrade the single point earth ground.

As the NIST says:
> A very important point to keep in mind is that your surge protector will
> work by diverting the surges to ground. The best surge protection in the
> world can be useless if grounding is not done properly.

A 'whole house' protector has that ‘always required’ low impedance (not low resistance) connection to earth. A plug-in protector obviously does not. Just another reason why telcos do not waste money on plug-in protectors. Just another reason why facilities that need to stop surge damage from lightning, instead, upgrade the earthing. Such as Orange County FL did to eliminate surge damage to emergency response facilities. Again, it will not let me post properly:
Triple w dot psihq dot com slash AllCopper dot htm

Any protector that works by opening a switch (ie double pole breaker) provides no protection. Critical to surge protection is how that 'whole house' protector connects to earth. Again, the expression is 'low impedance'. That means a wire that is as short as possible (ie 'less than 10 feet'). No sharp wire bends. No splices. That grounding wire must be separated from all other wires (just another reason why interior AC wires cannot provide earthing). All grounds (even from the telco installed for free 'whole house' protector and from the cable) must meet at the single point earth ground. Then the earthing system is typically upgraded or enlarged. After all, what provides surge protection from all surges - especially direct lightning strikes? Earth ground.

Either surge energy is *diverted* short and harmlessly into earth. Or that energy goes hunting for earth destructively inside the house. Either that energy is harmlessly absorbed in earth. Or that energy is destructively dissipated inside appliances. Surge protection means protection inside all appliances is not overwhelmed.

Which solution is better? Which solution also meets and exceeds post 1990 National Electrical code for earthing? Each surge protection layer is only as effective as its earth ground.