Earth/moon.

[JohnW2]

However, clearly distance does matter ...

Indeed. It's only 'simultaneously-touchable' things that really concern us, so anything significanly more than about 1.5m ought to be enough. In fact, it's very rare for people to do things with both arms stretched out sidewsys to their full extent, so less than that would probably usually be enough.

For those who like to scrape barrels, I suppose one might consider the possibility that someone might'extent their reach by having a lengthy conductive too/whatever in their hand, or if a group of people 'held hands' in a chain, but I'm not sure that I would be personally inclined to give too much weight to such considerations!

It's obviously a bit different when people can 'stand on soil', but they will rarely do that with bare feet, and I would suspect that almost any footwear would be enough to avoid a serious electric shock

 

[RandomGrinch]

In reality you need exactly the same protections as for any other IT system - that includes protection against line-line faults, and protection against shock for everyone involved.

I understand where you're coming from, and I may be talking utter rubbish, but at least in the short term - if the equipment for a Luna environment follows that of NASA and the ISS protocols - the risks to health from electric shock can be designed and risk assessed out.

Risk to Crew Health Due to Electrical Shock (Electrical Shock Risk) - NASA

It is important to protect humans from unintended electrical current flow during spaceflight. The thresholds for contact electrical shock are well

www.nasa.gov

Again, at least to start with, these will be highly controlled environments - the cost of developing systems for Luna use will be huge - the cost to additionally make the equipment inherently safe, when powered from a low voltage DC bus, is unlikely to break the bank.

It may also be worth considering (maybe coldly), that the risk of harm to the habitat could outweigh that of individuals. I.e. the priority may be to provide more mitigation measures to avoid electrostatic discharge, and the additional overload protection needed to help prevent fire, than to mitigate against a very low risk of electric shock.

Looking into the ISS power systems is fascinating. I had never considered the problems they have with space plasma causing a charge build up on the station, and how they get rid of it.
...and the ISS does use a 'single' point of 'grounding'!

 

[StephenStephen]

Indeed. It's only 'simultaneously-touchable' things that really concern us, so anything significanly more than about 1.5m ought to be enough. In fact, it's very rare for people to do things with both arms stretched out sidewsys to their full extent, so less than that would probably usually be enough.

For those who like to scrape barrels, I suppose one might consider the possibility that someone might'extent their reach by having a lengthy conductive too/whatever in their hand, or if a group of people 'held hands' in a chain, but I'm not sure that I would be personally inclined to give too much weight to such considerations!

It's obviously a bit different when people can 'stand on soil', but they will rarely do that with bare feet, and I would suspect that almost any footwear would be enough to avoid a serious electric shock

...though over the longer term you might need to factor in genetic drift under lower gravity towards taller humans with longer arms...

 

[JohnW2]

...though over the longer term you might need to factor in genetic drift under lower gravity towards taller humans with longer arms...

Maybe, but even if it happens, that sort of 'genetic drift' takes a very very long time, and I very much doubt that anything we know and discuss about 21st century electrical installations would be remotely relevant (if the human race still existed!) by the time arms had, in general, got appreciably longer

In any event, if you are thinking of Darwinian evolution, 'civilisation' has largely brought that to a halt as far as humans are concerned - I can't really see significant numbers of humans dying off before they reproduce because of their 'shorter arms' (and height)!