What causes power surges?

This Q & A is one of the thousands posted in our Technical Expertise area and answered by
our Voltimum Experts.

Question:
What causes power surges?

Answer: 
Lightning strikes produce the largest transient overvoltage events in electrical installations, creating
surges of thousands of volts lasting less than a millisecond. These can result from direct strikes, but
also (remarkably) strikes up to a kilometre away from the installation.

Man-made surges arising from switching event transients on the network, though much smaller in
scale, are more frequent and can stress electronic components, causing unplanned outages,
damaging or degrading equipment – and ultimately result in equipment failure.