Galvanic isolation of COM ports: is it required for industrial applications?

Galvanic isolation of COM ports: is it required for industrial applications?

In various industries, there are many devices with COM ports, usually RS-232, RS-422 and RS-485. System engineers and designers are often faced with a dilemma: whether to use a galvanically isolated COM port or not.

On the one hand, 1–2 kV COM port galvanic isolation can protect against sudden transient overvoltage on the line and static discharge. The port will not burn out, continuing to work normally instead. You don’t have to search for a working COM port, repair the broken one, or buy a new one. Isolation can be either built-in or a separate external device.

On the other hand, isolation of a COM port means additional costs, and in a project with many devices, the price difference may become significant. But, there may never be any overvoltage incidents, and everything will work perfectly for many years.

Do you think COM port isolation is worth its money?