by w_tom - 7/11/13 5:38 AM
In Reply to: To R. Proffitt by C-Little
> One of other options I am considering is a "Whole House Surge Protector".
Use concepts even introduced in elementary school science to separate hearsay from hard facts. Lightning seeks earth ground. A path for a 20,000 amp surge is via a wooden church steeple, destructively, to earth. Wood is not a good conductor. So 20,000 amps creates a high voltage. 20,000 amps times a high voltage is high energy. Church steeple damaged.
Franklin installed a lightning rod. Now 20,000 amps is via a wire to an earthing electrode. High current creates near zero voltage. 20,000 amps times a near zero voltage is near zero energy. Nothing damaged.
Lightning seeks earth ground. A lightning strike to utility wires far down the street is a direct strike, incoming to every household appliance, destructively to earth. Appliances are not a good conductor. So lightning creates a high voltage. Lightning current times a high voltage is high energy. Appliances damaged.
For over 100 years, facilities that cannot have damage installed superior earthing connected low impedance (ie 'less than 10 feet') via one 'whole house' protector. Then high current creates near zero voltage. 20,000 amps times a near zero voltage is near zero energy. No appliance is damaged.
Protection of a building is a lightning rod connected to 'earth'. Protection of appliances inside the building is lightning connected to 'earth'.
Some facilities have no protectors. But still have what provides that protection - single point earth ground. Protectors never do protection. Either a protector is a connecting device to earth (just like a wire). Or that protector only claims protection from another type of transient that is typically not destructive. Two completely different devices share a common name.
Critical is that low impedance connection. It must be short (ie 'less than 10 feet'). Wire must not have sharp bends, no splices, not inside metallic conduit, and must connect to 'single point earth ground'. All four words have electrical significance. And further explain why wall receptacle safety grounds are not earth grounds.
More responsible companies provide these superior solutions including Intermatic, Siemens, Ditek, General Electric, Square D, Syscom, Polyphaser, ABB, and Leviton. A Cutler-Hammer solution had even sold in Lowes and Home Depot for less than $50. Price does not determine quality. Some of the least 'quality' protectors sold for $80 and $120. Quality of protection is defined what something far more important - single point earth ground.
Also important in every useful answer are numbers. Lightning is typically 20,000 amps. A protector must not fail even from a direct lightning strike. Because the primary purpose of a protector is protection even from direct strikes. So a minimally sized 'whole house' protector starts at 50,000 amps. So that nobody even knew a surge existed. So that even a protector remains functional.
More numbers. A destructive surge is maybe hundreds of thousands of joules. How many joules does an appliance adjacent protector absorb? Hundreds? Thousands. Near zero protection. Effective protection means hundreds of thousands of joules dissipate harmlessly outside in earth. So that nobody even knew a surge existed.
Two completely different devices are discussed. Protectors that have no earth ground. And will somehow magically make that energy disappear. Or another completely different device that unfortunately shares a same name. The 'whole house' protector to protect everything for about $1 per protected appliance. Earth ground is where more of your money and most of your attention should focus. A protector is only as effective as its earth ground.
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