What’s the difference between voltage surges and voltage spikes and which is most damaging to electronic security systems?

A: Voltage surges are a rise in amplitude taking place over a short time and they last a minimum of 1 half cycle (that’s 1/120th of a second). Voltage surges are the result of powerful electric motors or equipment switching off and leading to a brief reduction in current load and a big increase in voltage. An air conditioning unit on low or mid cool mode is a classic culprit. As the compressor turns on and off line voltage can be pumped up by thousands of volts.

Meanwhile, voltage spikes occur when lightning strikes power lines or hits the ground near power cables. This causes a large and damaging voltage pulse that blasts down a cable and fries any circuitry that gets in its way. Lightning strikes are profoundly destructive. The associated spikes are momentary, they may only last milliseconds, but they’ll routinely reach thousands or tens of thousands of volts.

On a global scale lightning strikes destroy huge amounts of electronic equipment every year, a risk factor that can only be eliminated if electronic gear is always unplugged – something you just can’t do with security systems. The upshot of all this is that lightening protection strategies should be implemented that incorporate well-designed line protection and up to date insurance.