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And shouldn’t there be exactly one grounding point per building and definitely not one outlet randomly grounded to a pipe? Not an electrician but I’m pretty su

And shouldn’t there be exactly one grounding point per building and definitely not one outlet randomly grounded to a pipe? Not an electrician but I’m pretty sure that’s a major code violation and safety hazard.

chrisseaton 4y ago
> definitely not one outlet randomly grounded to a pipe? That's how it used to be done! Remember a lot of houses were built before electricity and it's been retrofitted over time.
- doubled112 4y ago
  A water pipe is bare copper straight to the ground. It makes perfect sense if you think about it. Pretty sure that is how it is done in my much newer than electricity build.
  - loeg 4y ago
    Old copper water pipes, yes. Obviously you can’t ground using a PEX pipe.
    - cesarb 4y ago
      Wouldn't it also need a continuous copper pipe until it meets the ground? A pipe being made of copper or iron doesn't mean it's not connected to a plastic pipe or adapter upstream; and I've seen plumbers using a rubbery-looking tape between the threads when screwing two metal pipes together, which might not be conductive.
      - finnh 4y ago
        I just fixed this situation in a house from the 70s. Cable coax lines grounded to a metal hose bib ... which, in the crawl space, switches to PEX about a foot away from the bib. Cable guy installing high speed internet was all "nope!". I think the previous owners just had crap internet and didn't ever get into why.
        sidewndr46 4y ago
        The coax shield must be broken somewhere between you and the service provider. "Grounding" a coax to PEX should never make a difference in any way.
        finnh 4y ago
        I think part of his worry was lightning strike busting their equipment. Unsure about the rest.
      - loeg 4y ago
        > Wouldn't it also need a continuous copper pipe until it meets the ground? A pipe being made of copper or iron doesn't mean it's not connected to a plastic pipe or adapter upstream Right. > I've seen plumbers using a rubbery-looking tape between the threads when screwing two metal pipes together, which might not be conductive Probably PTFE (teflon) tape. The thing to do with oldschool copper pipes though was to braze them together, which is conductive.
    - rpvnwnkl 4y ago
      I think the continuous water still maintains a ground path even in pex
      - bombcar 4y ago
        Water is actually not very conductive at all which is why you need to install ground links if you break into an existing grounded pipe. And the purpose of grounding the pipe isn't to use the pipe as a ground (some very old electrical setups may have done this), it is to prevent the pipe from getting energized by a wire or something resting against it. If the pipe is properly grounded, that'll short out a breaker.
cwillu 4y ago
Pipe is a great ground, if done properly. Nice big hunk of metal thoroughly embedded into the ground is all a ground plate is.
- otikik 4y ago
  The problem with “if done properly” is that you actually have to go and check. If you just “hope that it is done properly” you can have a lot of surprises, like lights going out when the sink gets full of water. Or spicy dishwashers. If you don’t know whether it’s properly done, it’s much more efficient to throw a ground cable from the nearest service junction than it is to “hope” and then have to fix things later.
- colechristensen 4y ago
  It’s not about whether or not pipe is a good ground. The electrical grounding for a building needs to be like a tree. No ground loops and exactly one grounding point. Arbitrarily adding grounds, especially through water pipes can do things like making all of the piping and water in the house hot if there is a fault somewhere and it definitely seems like that’s the case here. The whole idea is that the ground wire is the least resistance path for stray current to go to. When you have separate ground paths there can be a dangerous potential between ground wires and the least resistance path for stray current can again be you.
  - murderfs 4y ago
    There's a difference between the electrical return path (aka neutral) and protective earth (aka ground). Earth is purely for safety: you earth the metal chassis of appliances so that if for some reason they get shorted to hot, the current has a low impedance path to earth and your breaker will pop. It's perfectly acceptable to have an independent earth at every single outlet, as long as you're earthing to an acceptable source (which, AFAIK, means driving an earthing rod into the ground, because pipes aren't legal in the NEC anymore).
    - sidewndr46 4y ago
icehawk 4y ago
You can have multiple ground points per building as long as the ground points are bonded to each other. You can only have a SINGLE tie between neutral and ground. What we don't know here is if the piping is tied to a grounding rod, or if there is a grounding rod or if the piping is the ground point.

chrisseaton 4y ago

> definitely not one outlet randomly grounded to a pipe? That's how it used to be done! Remember a lot of houses were built before electricity and it's been retrofitted over time.

doubled112 4y ago
A water pipe is bare copper straight to the ground. It makes perfect sense if you think about it. Pretty sure that is how it is done in my much newer than electricity build.
- loeg 4y ago
  Old copper water pipes, yes. Obviously you can’t ground using a PEX pipe.
  - cesarb 4y ago
    Wouldn't it also need a continuous copper pipe until it meets the ground? A pipe being made of copper or iron doesn't mean it's not connected to a plastic pipe or adapter upstream; and I've seen plumbers using a rubbery-looking tape between the threads when screwing two metal pipes together, which might not be conductive.
    - finnh 4y ago
      I just fixed this situation in a house from the 70s. Cable coax lines grounded to a metal hose bib ... which, in the crawl space, switches to PEX about a foot away from the bib. Cable guy installing high speed internet was all "nope!". I think the previous owners just had crap internet and didn't ever get into why.
      - sidewndr46 4y ago
        The coax shield must be broken somewhere between you and the service provider. "Grounding" a coax to PEX should never make a difference in any way.
        finnh 4y ago
        I think part of his worry was lightning strike busting their equipment. Unsure about the rest.
    - loeg 4y ago
      > Wouldn't it also need a continuous copper pipe until it meets the ground? A pipe being made of copper or iron doesn't mean it's not connected to a plastic pipe or adapter upstream Right. > I've seen plumbers using a rubbery-looking tape between the threads when screwing two metal pipes together, which might not be conductive Probably PTFE (teflon) tape. The thing to do with oldschool copper pipes though was to braze them together, which is conductive.
  - rpvnwnkl 4y ago
    I think the continuous water still maintains a ground path even in pex
    - bombcar 4y ago
      Water is actually not very conductive at all which is why you need to install ground links if you break into an existing grounded pipe. And the purpose of grounding the pipe isn't to use the pipe as a ground (some very old electrical setups may have done this), it is to prevent the pipe from getting energized by a wire or something resting against it. If the pipe is properly grounded, that'll short out a breaker.

cwillu 4y ago

Pipe is a great ground, if done properly. Nice big hunk of metal thoroughly embedded into the ground is all a ground plate is.

otikik 4y ago
The problem with “if done properly” is that you actually have to go and check. If you just “hope that it is done properly” you can have a lot of surprises, like lights going out when the sink gets full of water. Or spicy dishwashers. If you don’t know whether it’s properly done, it’s much more efficient to throw a ground cable from the nearest service junction than it is to “hope” and then have to fix things later.
colechristensen 4y ago
It’s not about whether or not pipe is a good ground. The electrical grounding for a building needs to be like a tree. No ground loops and exactly one grounding point. Arbitrarily adding grounds, especially through water pipes can do things like making all of the piping and water in the house hot if there is a fault somewhere and it definitely seems like that’s the case here. The whole idea is that the ground wire is the least resistance path for stray current to go to. When you have separate ground paths there can be a dangerous potential between ground wires and the least resistance path for stray current can again be you.
- murderfs 4y ago
  There's a difference between the electrical return path (aka neutral) and protective earth (aka ground). Earth is purely for safety: you earth the metal chassis of appliances so that if for some reason they get shorted to hot, the current has a low impedance path to earth and your breaker will pop. It's perfectly acceptable to have an independent earth at every single outlet, as long as you're earthing to an acceptable source (which, AFAIK, means driving an earthing rod into the ground, because pipes aren't legal in the NEC anymore).
  - sidewndr46 4y ago

icehawk 4y ago

You can have multiple ground points per building as long as the ground points are bonded to each other. You can only have a SINGLE tie between neutral and ground. What we don't know here is if the piping is tied to a grounding rod, or if there is a grounding rod or if the piping is the ground point.