In a farm setting, my brother asked me what could cause him to get a shock from an outdoor hose bib at the pump house? He was prepping for freezing weather and disconnecting hoses from hose bibs. There was a ground wire attached (poorly) to the galvanized pipe that was going into the the buried pipe. He also mentioned that he noticed arcing (as in SPARKS!!!!) at the piping when the pump started.
What could cause me to get shocked by a hose bib?
When my bros called for help, I took a few tools and meters with me. Took a couple of measurements from the pipe to actual ground...very low voltage....OK....now what? Fiddled with the ground wire attached to the piping and it started arcing due to the poor connection! I thought Oh H E double hockey sticks this is really bad. I have 2 amp clamp type DMM and both said, even though the readings where varying the both read between 5-10 amps on a EGC (equipment grounding conductor) which is a ridiculous amount of current for and EGC. I told them not to touch any metal pipes , call the PoCo and tell them 3 words to get immediate attention: potential lost neutral and that would get their attention.
The PoCo showed up quickly and determined they didn't have a problem but the tech noticed a splice in the triplex going to the farm building and because he had a bucket truck, he volunteered to inspect the splice. Sure enough, it was a damaged / lost neutral. They fixed it at no charge even though it was on the customer side of the meter.
... and why it was outlawed as of NEC 1999 or 2008 for sub panel feeders. And 1996 for ranges and dryers. And 1966 (pre-moonshot) for everything else and as early as 1955 for some things.
I'm using the big font in the hopes that they can hear me across the pond :)
"I don't need separate neutral and ground! They're the same thing!" Actually, they're not. Neutral is the normal current return. Ground is the safety shield. When you mix them it's not ground anymore. It's neutral and you don't have a ground.
In fact, as we stamp it out in the USA it's resurfacing in the UK. They don't have local ground rods on their dwellings, they take ground from the utility. (called TN-S in their scheme). And of late, the utilities are treating N and G as the same thing and combining them, in a single PEN (Protective Earth and Neutral) wire. This scheme is called TN-C-S. This may be done silently without notice in the course of maintenance on supply lines. And when the PEN wire breaks, it does the same thing as you experienced - energizing all the "grounds" which aren't really grounds, since PEN isn't ground.)
But even worse, it breaks the GFCI protection. John Ward has a lovely video on the topic.
(not a perfect metaphor because the British only have one "hot" wire. Imagine a second hot.)
And all that would be something UKers mostly live with, as people call when the power goes out, and with the high-density housing there, only a minority of people have electrical tools in their hands while in contact with actual dirt. However, the UK is starting to charge electric cars, and that has pushed the problem to the forefront and demanded positively byzantine schemes to protect you from "protective earth".
Here's the important part: when you run 4-wire feeder to a subpanel, you separate neutral and ground at the subpanel. (and bond your local ground rods to the ground, not the neutral).
The trick with this is... most people with any experience installing overhead lines do most of their work for the power company. Who follows different rules, as you may have noticed. So when you ask for an overhead line feeder, they will automatically reach for the triplex. You will need to jump all over them and say "no no, quadplex. REALLY." Best to just fib and tell them you have a 3-phase converter in one building and want to distribute 3-phase to the other building. Fix it after they're gone lol.
I suppose you could obtain an XHHW wire and furl it onto the existing overhead line.
