Earth Pit Distance

You will find your answer here,but you must look for it.

https://inspectapedia.com/plumbing/Gas_Meter_Clearances.php

Well you probably wouldn't want them touching...probably a safe distance should be tested to be sure...

https://www.coleparmer.com/tech-article/ground-testing

https://www.ecmag.com/section/codes-standards/grounding-and-bonding-gas-piping

It depends on the electrical code applicable in the country of installation, which has been withheld from the forum.

I'm certain such a standard exists for many locations and that there are many licensed individuals with the authority to say. This brings to my mind a few questions.

Where will this be installed?

Will our recommendation for a distance add any value to this project?

The short-circuit withstand current of 25 kA/1 sec it is not referring to the electrode but to an installation. We don’t know how many electrodes are used here and the what is grounding resistance. If we take only one pipe for grounding in 100 ohm.m earth, according to BS7430 we get only 32 ohm that means we need 814 kV in order to produce 25 kA. Let’s say the soil resistivity it is only 10 ohm.m [close to a river] the resistance presented by one steel pipe of 3m and 3/4” diameter is 3.25 ohm then we need only 81 kV for 25 kA.

In my opinion I think it is about low voltage [230 V] so the maximum short-circuit current it is only about 7 kA.

In my opinion since the installation is in open air it is an unclassified zone, where it is not a hazardous location for any distance. The connection of the grounding cable with the electrode may be enclosed-for more protection never the less if it is not any switching device it is not required by NEC art.500.

<...Fault current: 25kA for 1 sec...earth electrode...>

That's a bit unlikely. Here's why.

If the earth electrode resistance back to the supply were, say, 30Ω (not unrealistic), then the supply voltage would need to be 750kV(!) to produce such a fault current.

A fault current of 230V/30Ω would be 7.6A, which is well enough to open a residual current circuit breaker of 30mA or even 100mA, and insufficient to open a regular circuit breaker of 6A rating, as might be found on a lighting circuit, for quite some time. Higher-rated breakers would completely ignore it.