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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?

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    Self-answered questions are 100% great! Don't make a big deal out of it, just do it. ;)
    – FreeMan
    Feb 1 at 17:03
  • I'm assuming you're not shuffling around outside with your fuzzy slippers?
    – Huesmann
    Feb 2 at 19:19
  • @Huesmann Yeah my PFBS (pink fuzzy bunny slippers) are soooo comfy when when wet and out side and working on a ground fault, get a nice tickle at times! LOL (just kidding of course). I was very careful. My bros are fish farmers, usually in wet waders, wet hands...good conductors, so it wasn't surprising that they would feel it first.
    – George Anderson
    Feb 2 at 20:55

2 Answers 2

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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.

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    Unusual result of a lost neutral, so most people might not expect shocks from piping to be the cause.
    – crip659
    Jan 31 at 20:02
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    @Ruskes nope, galvanized steel the whole way and buried.
    – George Anderson
    Feb 1 at 4:00
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    @GeorgeAnderson In a farm context you have another issue, especially if dealing with cattle or horses... The potential gradient in the ground close to that earth can easily be great enough to (worst case) kill a horse or cow, and more commonly will significantly reduce milk production in cattle if that is your thing. Combined earth/neutral once past the suppliers demarc are a bad idea anyway, and a horrible idea where quadrupeds are concerned. There is plenty of literature around this in dairy farms.
    – Dan Mills
    Feb 1 at 15:13
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    @DarrelHoffman Yea, just a distance thing, and it tends to put the current thru places that matter to the critters continued functioning. You doing it is not mostly going to dump the current across your ticker.
    – Dan Mills
    Feb 1 at 16:15
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    @FreeMan actually they got thru to a human pretty quickly...must have been a slow day! But once we said "potential lost neutral" there were out there pretty quickly.
    – George Anderson
    Feb 1 at 18:25
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That's what happens when you combine neutral and ground

... 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.

enter image description here

(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".

4-wire feeders are your friend. Run quadplex.

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.

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  • That's a great video explanation. Thanks for sharing
    – raddevus
    Feb 1 at 14:15
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    I'm not quite following what you are saying about running quad plex? Here in the US residential service is typically serviced by a transformer that supplies 240v across the two hots and 120v via a center tap (GNC: Grounded neutral conductor) on the transformer. So if someone wanted to do the quad, where would the 2nd ground wire be connected? Both would be bonded in the main panel, so it would be a double run back to the transformer...neutral and ground, what's the point?
    – George Anderson
    Feb 1 at 14:37
  • @GeorgeAnderson I don't quite understand the question but there is only one ground, not a separate ground for each hot. Same for neutral, there is only one.
    – user253751
    Feb 1 at 16:59
  • @user253751 agreed....I just don't understand the benefit of quad-plex and where to connect it to the transformer since the transformer only 2 hots for 240v and a center tap for 120v, which is also grounded.
    – George Anderson
    Feb 1 at 18:22
  • @GeorgeAnderson because neutral and ground should only be connected to each other at one point. Yes, it's not necessary in theory if everything is normal. But if something goes wrong, the outcomes are a lot better if neutral and ground are kept separate. That's why they have to be kept separate. For example, if the neutral wire gets accidentally broken it can become live and shock you, so if you used the same wire for neutral and ground, now ground is disconnected too, and ground is live too, and that's bad.
    – user253751
    Feb 1 at 18:24

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