Effectiveness
SAFEGROUND®
SAFEGROUND®
The effectiveness of the surge protector depending on the grounding status
The effectiveness of the surge protector depending on the grounding status
If the surge protection device does not have an adequate path to ground for discharging voltage peaks, the protector will be forced to operate under sub-optimal conditions.
The effectiveness of surge protectors is indeed closely linked to the grounding system, since a high impedance path may increase the exposure of sensitive equipment to the effects of the overvoltage.
To understand the relationship between the quality of the ground connection and the effectiveness of overvoltage protection, people often use a very intuitive hydraulic simile (Figure 1). If we equate the energy of the overvoltage to a specific volume of liquid, the ground connection may be thought of like a funnel. There is a direct relationship between the diameter of the funnel opening and the quality of the ground connection. Once the funnel has drained the entire volume of liquid, the overvoltage will have been shunted to ground and the equipment will see a completely normal voltage.
Figure 2 compares what happens to a bad ground connection (funnel on the left – small opening) to what happens to a good one (funnel on the right – big opening) in the event of an overvoltage. We can see how a ground connection with higher resistance (funnel on the left) is saturated with the energy of the discharge (the funnel overflows because it is incapable of draining fast enough). Intuitively, this prolongs the time during which the equipment to be protected is subjected to the effects of overvoltage, and which therefore suffer more wear (the funnel takes longer to empty due to its smaller opening).
Since all the equipment is referenced to ground, this can even lead to the current, unable to find a better escape route, doing direct damage to the equipment and rendering the protection ineffective (Figure 3). In the extreme case of loss or lack of a ground connection, the surge protection device becomes totally ineffective.
