Surge protection – when should I use it?

bg triangle top left

Surge protection is the protection of electrical equipment from dangerously high voltage spikes or surges. The most common cause of voltage surges is lightning strikes.

A surge protector or surge diverter generally works by diverting the dangerous voltage to ground (earth), and thereby keeping the voltage within a range that electrical components can safely handle.

Where is surge protection used?

In the context of industrial control panels, lightning or surge protection can be fitted to:

  • Incoming power to the control panel
  • Sensitive internal equipment such as DC power supplies and PLC hardware
  • Analog instrument connections
  • Digital instrument connections (not very common)
  • Radio antenna connections
  • Data cabling e.g. Ethernet, serial or phone lines

Surge protection is most commonly fitted to incoming power. It’s highly recommended in areas that may be subject to lightning, particularly exposed equipment such as a radio antenna mounted on a high pole, or sensors mounted out in the open. Where all field equipment is sheltered from lightning strikes inside a container or building, the only likely way a surge can enter the control system is via the incoming power cables –  protection on the incoming power only is generally sufficient.