Operation of the lightning guard

The Lightning Guard looks like a simple product, but in terms of technology it is a complex matter. Hereunder a short summary of the operation. The Lightning Guard does not protect against direct lightning strikes, for direct lightning strikes (but direct lightning strikes are rare), lightning protection rods with earth down conductors are commonly used. An indirect lightning strike will enter the home mostly via the mains, either through Line, Neutral or Ground. (This occur often)

The Lightning Guard has to absorb brief power surges from the mains that can occur between L (line), N (neutral) and G (ground) or has to guide it to ground. Power surges may occur due to indirect lightning strikes or peaks on the mains. The Lightning Guard do not protect against a long time overvoltage from mains, for example when there is 380V for 30 minutes on the mains.

For the Lightning Guard MOV’s (Metal Oxide Varistors) are used, which can absorb the energy of power surges. As soon as the voltage rises above a certain level, the MOV will conduct a current. The voltage will therefore be limited and the current that is running will be growing rapidly (the resistance of the MOV will become lower). The energy that is going through the MOV is being transformed into heat. As a result the MOV can become warm, and certainly when it is degraded after a certain period of time, it even will get to hot that This is the reason why we built in always a temperature protection in combination with a MOV, which will shut off the MOV when it will become too hot.

Most household appliances are tested to withstand power surges of 1,5Kv, but peak surges in a home can be as much as 5 to 6Kv. This means that the Lightning Guard has to absorb approx. 6Kv in order to protect the appliances. In a ratio from 10 – 35 meters the Lightning Guard can absorb this power surge for appliances connected to the same grounded-group within 1ns (faster as the appliances). Recommended is a radius of 10 meters for protection. As every home has different wiring, the further away the appliances, the less impact the lightning guard has due to the slower reaction time. In a non-earthed group, the Lightning Guard will absorb the peak surge and convert it to heat to protect the appliances. The Lightning Guard has been tested according IEC/EN 61643-11 / DIN VDE 60884-1 and an absorption of 9Kv was passed without any problem.

The Lightning Guard is based on MOV’s and a MOV outdates (deteriorates) with the amount of lightning and the processing of the strength of the power surges. A common rule is that a MOV cannot handle more than 10 surges in its lifetime.

Furthermore there are regulations for the enclosure of the product, all parts need to be double isolated and if an MOV does brake, the enclosure needs to stay intact.