Think of us as a TN-C world in much need of TN-S, but stubborn thanks to (cough POCOs cough) who don't like running more conductors then that which gets the lights lit. And wants the customer paying for the earth electrodes.
The soviet union and much of far eastern Europe had TN-C right up to the socket outlets until the mid 90s. It seemed like a good idea- I mean why waste money on an extra conductor? That is until a failing connection burnt itself open- putting 220 volts on every metal frame on that circuit. Enough of an issue that it influenced the way splices were made:
https://youtu.be/KgOKhfVON4Y?t=317
A "good" set of splices:
https://youtu.be/udzayPc9mME?t=358
I have a furman monster (currently boxed up), it's a plug in unit. 120v. The line in ground pin of the plug is common to the chassis. The ground on the secondary is floating. to a gfci receptacle.
I originally mounted it to the rails of the rack with all the all the other equipment installed ... audio hummed and buzzed away.. realized what was going on, Isolated the monster chassis from the rails and silence.
kept distance between house ground and equipment..
probably dangerous, but silent...
(sitting in a box now, it's real silent now)
So maybe Mr Furman could do
lunch with the poco's?
Or maybe the poco's should consider our NEC250.32B's modern (
i forget the cycle) update of isolation?
On all my farm jobs they (
the poco) eventually advise / install an isolative xfomer, meanwhile i'm bonding
anything and
everything that doesn't move so the herd of
bovine resistors can trade notes with all the crows on the poco wires....
Then there's all the
M.E.N. sytems in what little industry we've left around. Some of it may be
antiquated , yet the same art 230/250/450 NEC applies pursuant to an entire structure assuming different
potential juxtaposed to distances and loads.
Most of it went w/out note, until the digital age decended w/all it's sensitive electronics
equopotential takes on a certain
perspective , when the potential is
always there.....
art 230, 250, 547, 640, 645, 646 , 647, 680 all start to read the
same in the sense of
theory addressing it
~RJ~
