Is SAT grounding possible via a 7x2.5mm² cable?

It is dangerous to make such statements!
Driving slowly into the wall twice also doesn't hurt as much as once fast.
Conductor resistance, surface, etc. are massively different. Then there are funny effects with surface currents, solid material vs. stranded wire, etc. Which of the materials is better/at all suitable, I would not decide based on "should". Standards have a purpose and are mostly scientifically founded. Especially with such very well describable physical things.

And I definitely would not consult a practitioner here. Because I hope no practitioner builds so many houses that he experiences a relevant number of lightning strikes in his professional life. The statement "has always worked so far" is therefore probably only because he hasn’t had a strike in any of his installations yet.

Which statement do you mean exactly? I don’t read here that I have recommended anything even slightly. Primarily, I said that such a part definitely has to be grounded. You should have better quoted the comment before that.
And if that were physically not a problem, but someone demands green-yellow as identification, I wouldn’t care whether that is VDE compliant or not.

The pro in this question here would be

Because the naughty Dipol habitually attached a standard with a link, he was excommunicated, and that is why your "reputation" did not get through. ;)

With delay under the star-nick my comment as RFT antenna expert:

Once again, the temporary ban on multi-wire grounding conductors shines through from the OP’s question, which has long been lifted in the DIN EN 60728-11 (VDE 0855-1), primarily relevant for antenna safety, and has never applied in lightning protection construction. Grounding conductors for antennas subjected to lightning currents as well as lightning protection equipotential bonding conductors are standard-compliant if the individual wires have at least 1.7 mm diameter, which was also meant by the OP with the 7 x 2.5 mm².

With connectors designed for this purpose, 16 mm² can safely conduct extremely rare monster lightning currents well over 200 kA to ground without damage. But every chain is only as strong as its weakest link; connectors for antenna grounding conductors must be certified according to testing standard DIN EN 62561-1 in class H = 100 kA.

This applies both to the grounding conductor connection at the antenna mast as well as at its base point, usually the main grounding bar, which must be designed for lightning protection equipotential bonding; for 16 mm² Cu this requires tension clamps. Shields of antenna cables of antennas subject to grounding obligation must also be connected to the grounded antenna mast via grounding block or grounding bracket with at least 2.5 mm² Cu (protected installation) or 4 mm² Cu (unprotected).

Speaking of standard or paragraph riders: that is not an insult in forums but a compliment, usually given by norm-ignorant envious people. :cool:

Perfect…exactly what I expected! :-)

No, at least one 10 sqmm solid conductor is mandatory, actually you are not even allowed to use a 16 sqmm with single wires.

No, at least one rigid 10mm² conductor is mandatory, actually you are not even allowed to use a 16mm² with single cores

This supposed regulation exists exclusively in your norm-distant imagination. :mad:

Grounding conductor cross-sections of 10 mm² Cu and 16 mm² Aluminum are the standard status after the obsolete national VDE 0855 Part 1/07-71. Since VDE 0855 Part 1/05-84, that is now 38 years (!), grounding conductors for antennas of 16 mm² Cu, 25 mm² Aluminum and as before 50 mm² steel/tinned zinc are required.

Hopefully, you are not working commercially in antenna construction. If so, for the overdue training a quote from the current standard:

A suitable grounding conductor is considered a wire with a minimum cross-section of 16 mm² Cu, insulated or bare, 25 mm² Al, insulated, or 50 mm³ steel.

A dreadful German, but still clear language, there is no more question of 10 mm² Cu.

I will not further elaborate on the temporary ban on multi-stranded conductors in antenna construction, which still lingers in some minds and, although it never applied to lightning protection or photovoltaic systems, is wrongly transferred to them by those unfamiliar with the standards. Multi-stranded conductors, which used to be strictly prohibited in antenna construction but are common in lightning protection, are now also permitted in antenna construction subject to special connectors.

I want to install my dish soon. For grounding, I plan a 16mm2 grounding cable between mast and house equipotential bonding rail, and for the potential equalization between mast, grounding block with surge protector, multiswitch, and house equipotential bonding rail a 4mm2 grounding cable.

Now I have two empty conduits running from the attic to the utility room. Can I put all cables (grounding + 4x coaxial) into one empty conduit? A photovoltaic system is planned eventually. That will surely require grounding as well. How should I divide the individual cables? Grounding all in one empty conduit and the rest in the other?

For my safety, I want the lightning protection to be inspected. What measurements are performed?

We have installed a ring earth electrode in the ground and connected it to the foundation slab (steel). In the utility room, the conductor rises, where the house equipotential bonding rail was installed. Additionally, I have a conductor rising at a corner of the house. This should also be connected to the ring earth electrode. I believe the shell builder placed it there because our construction specification included this. Would this be suitable as grounding for a lightning rod or not?