[servo_sausage]

Is that something other than a labelling convention? Is ground actually connected to a earth stake?

[CamperBob2]

Cathodic protection against corrosion was the goal of using -48V, in the telcos' case.

[myself248]

And the telegraph lines before that.

[magicalhippo]

> Is ground actually connected to a earth stake?

Yes, or something similar[1]:

A few of the more efficient grounding electrodes for buildings and structures are:

- Metal Underground Water Pipe

- Metal In-ground Support Structures

- Concrete-Encased Electrode (also known as “footer ground” or “Ufer ground”).

- Ground Ring

As mentioned this is particularly important for telecom and similar systems which have signal wires going literally through the ground.

[1]: https://www.nfpa.org/news-blogs-and-articles/blogs/2021/09/2...