TVSS versus Surge Arrestor

[agapeagain]

Why would a 208/120V panel need a TVSS AND a Surge Arrestor?
What is the difference between a TVSS and a surge arrestor?

 

[7anoter4]

Surge protection takes two forms:
1) A surge arrester is connected at the main circuit breaker panel and provides protection for the entire building from surges traveling into the building on the electric utility's wires (e.g., lightning strikes, switching reactive loads, etc).
The main task of operation of surge arrester is to divert the overvoltage charge from line to earth. The surge arrester
provided with varistor responds to every change of voltage on its terminals. The surge arrester, when is subject to the
normal operation voltage, conducts the microamps current, but in case of occurrence in the line electric charge, causing the voltage higher than Uc (for example charge of direct or indirect lightning stroke), the arrester diverts this charge to the earth avoiding the occurrence of overvoltage that could lead to the failure of insulation of equipment.
2) A surge suppressor connected between the wall outlet and vulnerable equipment (e.g., computer), often in an outlet strip or hidden inside the equipment itself.
Transient Voltage Surge Suppression (or TVSS) technologies protect microprocessor operations from damage due to switching surges or surges associated with events like power outages.
So, what do you need is a surge arrestor-if no microprocessor is included in this low voltage panel.