NJWIRENUT said:
"A TVSS relies on a short, heavy, low-impedance path to earth ground".
Sorry, but earth or ground has nothing to do with TVSS and has no function. Any TVSS device is just a clamp to fire at a prescribed voltage and acts as a short circuit between the two points it is connected too.
For example lets say you install a TVSS at the service entrance on a single phase 240 volt service. The best units (I am talking thousands of dollars) only have two surge protection (SPD) devices installed. One each from from line-to-neutral. You will not find a device installed L-G or N-G. Absolutely no need for one.
Once You get down stream from the N-G bond at the service, a SPD between L-G and N-G becomes usefull, but earth or ground still has no function. All you are doing is clamping the voltage between L-G or N-G at the receptacle or point of use. The EGC impedance is an open circuit to earth at lightning frequencies.
[This message has been edited by dereckbc (edited 12-13-2005).]
