Grounding question

[nix85]

Floor that is all that is common knowledge most of it is already mentioned,
or perfectly assumed.

here is a video explaining all those basics nicely
https://www.youtube.com/watch?v=P-W42tk-fWc

you might just have simply written redundancy

also "Both the common and the ground wire are neutral to earth ground (ideally)."
this is often not the case cause there is potential between remote and local earth
which will trip the RCD if "neutral" is earthed.

sometimes it's even possible to power small appliances between neutral and ground
https://www.youtube.com/watch?v=BF0CS8aY1CY

again, there is no such thing as "phase" and "neutral", these are nonsensical terms
that just confuse the public.

in your american split phase system you have 3 wires coming from the pole transformer
2 of which might be called "common" cause one of your two 120v phases is common wire of the 3 phase transformer and your household "common" is common for two sides of that single phase winding.

the ONLY difference is that so called neutral/common is often but not always earthed.

Jerry Volland, all you wrote is basics all of us know

fritznien no, goal is not to be cheap on wire but to clear this up.
yea "any fault in the neutral will let the case rise to full voltage and ZAP"

but no zap happens in that scenario if you have RCD which you surely do
hopefully one with less than 500mA tripping current.

you might as well think of similar scenario where fault happens in the ground
wire and again casing is live, thankfully RCD again saves you

also i did not say ground wire is to handle lightning but earthing, that is, metal rod on your roof connected to the rod in the ground

i will accept redundancy as an answer

[kajunbee]

So I see at least two scenarios. One in which neutral and ground are connected at load, but only the neutral is connected to rcd.  In this case rcd will trip when load is connected. The other scenario is where neutral and ground are connected at load and also at rcd. In this case the rcd will not trip. Now suppose there is short to the case but it is perfectly isolated. In this case the rcd would not sense a fault, correct. You now come along and touch the device and provide a path to ground. As I see it the rcd will trip but you might feel a brief shock. But if case is grounded separately the rcd hopefully trips before you make contact with the faulty device. Does anyone else see it the same way or am I way off.

[nix85]

it makes no difference if casing is connected to neutral in the appliance
or few meters away in the breaker panel

in any case if "live" touches the casing MCB will trip cause of short circuit,
not RCD. in a case MCB fails for some reason and casing is live
and grounded person touches it small current will flow through
a person but only for 25-40ms. now we come to sensitivity of your
RCD

"To prevent electrocution, RCDs should operate within 25–40 milliseconds with any leakage currents (through a person) of greater than 30 mA, before electric shock can drive the heart into ventricular fibrillation, the most common cause of death through electric shock."

we for example have 500mA RCD so it is questionable would it save a person

this whole grid is shit and requires this overcomplex protection,
with greater potential for failure.

we should be using say 30v instead of 120 or 240 at cost of thicker conductors
but no danger of shock.

(yea, theoretically even 24v can kill you if you are wet but still)

grid of the future is no grid

[nix85]

i am looking at these high voltage long distance dc transmission lines
gaining popularity lately and transmission lines in general
such monstrosity, obsolete for 150 years

[fritznien]

it makes no difference if casing is connected to neutral in the appliance
or few meters away in the breaker panel

in any case if "live" touches the casing MCB will trip cause of short circuit,
not RCD. in a case MCB fails for some reason and casing is live
and grounded person touches it small current will flow through
a person but only for 25-40ms. now we come to sensitivity of your
RCD

"To prevent electrocution, RCDs should operate within 25–40 milliseconds with any leakage currents (through a person) of greater than 30 mA, before electric shock can drive the heart into ventricular fibrillation, the most common cause of death through electric shock."

we for example have 500mA RCD so it is questionable would it save a person

this whole grid is shit and requires this overcomplex protection,
with greater potential for failure.

we should be using say 30v instead of 120 or 240 at cost of thicker conductors
but no danger of shock.

(yea, theoretically even 24v can kill you if you are wet but still)

grid of the future is no grid

it makes every difference where the neutral is connected. in the panel the ground is tied to earth,
no matter what goes on in the appliance and neutral the ground line will remain safe.call it redundant if you like it is safe. your RCD breaker will kill somebody. at 500ma you are going to be standing there with smoke coming out your ears 6 months later when they cut off your power for non payment. also i have one GFI in my house, i'm sure many are similar. i bet there are service panels in my countythat still have fuses. would you trust your life to a 30 year old RCD?
grounding is not complicated, run the ground wire to every metal junction box where you have connections.it is also the law as it is required by code.