5 ms·

Edit: nope. See reply. Klein Tools RT210 Outlet Tester, $13, would've detected this in a jiffy. https://www.kleintools.com/catalog/electrical-testers/gfci-out

by js2 4y ago

Edit: nope. See reply. Klein Tools RT210 Outlet Tester, $13, would've detected this in a jiffy. https://www.kleintools.com/catalog/electrical-testers/gfci-outlet-tester https://www.kleintools.com/catalog/electrical-testers/gfci-o... (If I ever have more money than I know what to do with, one of the things I'll do with it is buy Klein's entire catalog of tools. Just because.)

jcalvinowens 4y ago
No it wouldn't. The neutral was cut, that tool can't reliably identify that problem. The tester will see a voltage that depends on the other loads in the house, which might be lower or higher than normal. Your tester would also still show the outlet as grounded, because it just checks for continuity from neutral to ground at the outlet, which exists even when the utility neutral is broken because of the neutral-ground bond at the service entrance. A common misconception is that the neutral-ground bond at the service entrance is what makes the system grounded. That is not true: it is the neutral-ground bond at the transformer that makes the system grounded. If you break the utility neutral wire, the ground (earth) is too bad a conductor to work in its place, even if the transformer and panel both have intact neutral-ground bonds.
- js2 4y ago
  You're right. That makes sense.
- mindslight 4y ago
  > A common misconception is that the neutral-ground bond at the service entrance is what makes the system grounded. That is not true: it is the neutral-ground bond at the transformer that makes the system grounded Er, what? It's any/all of the neutral-ground bonds that make the system grounded. The more ground connections, the more redundancy and lower impedance. ... which is probably why the plumber didn't worry too much about disrupting the building's ground connection. If everything else is wired up right it's not going to be that big of a deal - perhaps a few volts on the building's grounding conductor versus actual earth, due to the current on the service neutral.
  - jnsaff2 4y ago
    Yeah. Here in EU I get 3 phase cables only coming from the transformer. Then at my house a grounding rod is used to give combined Protective Earth and Neutral (TN-C). At my house main panel they are split into PE and N (TN-S). They are never connected house side and I now have combo RCD’s so each automatic fuse is also an RCD. EDIT: I was wrong, there are 4 conductors coming from the transformer, 3 phases and a Neutral. Phase-Neutral 230V and Phase-Phase 400V. Grounding rod connects to the Neutral and 4 conductors come to the main electricity cabinet. There Neutral and PE are split.
    - mindslight 4y ago
      It sounds like the branch circuits must be wired delta (phase to phase, rather than phase to neutral). What's the neutral actually do? Or does your earth have low enough impedance that you can get away with low power loads returning unbalanced phase current through the earth?
      - jnsaff2 4y ago
        Earth is used as return path for any current. Someone described it as an endless source/sink for electrons. I don’t have any delta loads in my house, but I could of course if I needed to.
        mindslight 4y ago
        That's odd, and I can only think you must live in an area where the earth is conductive enough to carry significant current (or are the cables coming from the transformer inside a metal conduit?) The earth is nothing like "an endless source/sink for electrons". Rather, electricity always flows in a complete loop (circuit), and the current flow is somehow getting back to the transformer to complete that circuit.
        derefr 4y ago
        All you need to conduct long distances through the earth is a big buried plate to spread the current across. See e.g. https://en.m.wikipedia.org/wiki/Earth-return_telegraph https://en.m.wikipedia.org/wiki/Earth-return_telegraph. > The earth is nothing like "an endless source/sink for electrons" It’s a bounded sink for electrons, though — i.e. it has capacitance — insofar as a positive ionization required for a static discharge (lightning) built up in the earth can be “spent” by grounding voltage into it. You can think of the earth as a constantly-recharging (but sometimes rapidly discharged) anti-supercapacitor. Just like the atmosphere is a constantly recharging (but sometimes rapidly discharged) regular supercapacitor. Ignoring that, though, what people usually mean by this is that the combined neutrals of the entire power grid are on the other end of any dumping of current you’re doing into ground. It’s not just your local neighbourhood transformer; if your transformer’s resistivity increased too much due to the added ground-return current, then the rest of the current could find another path to some other, further-afield transformer, or multiple such. Or maybe even the local power plant. Or some unrelated grid-connected power plant. Or—dangerously—a power plant connected to a physically proximate but electrically disconnected grid… which is in part what makes power-factor wobble around so much in black-start grid power stations.
AdamJacobMuller 4y ago
Even if it wouldn't have detected this problem, that Klein tool detects a lot of problems which don't immediately cause weird issues. E.g. open grounds, flipped ground/neutral, flipped hot/neutral. Lots of things which work perfectly fine, until they don't. The GFCI tester on them is great too. Klein makes a marginally more expensive version ($20) which does show voltage and you could have seen the symptoms of this particular problem. https://www.amazon.com/Receptacle-Electrical-Klein-Tools-RT250/dp/B08QW7K1JJ https://www.amazon.com/Receptacle-Electrical-Klein-Tools-RT2...
- electriclove 4y ago
  How would the symptoms manifest on this tester? Would it show a different number?
  - NavinF 4y ago
    Yeah and that number (voltage on one leg) would increase well above 120V when you place a large load on the other leg using other devices like space heaters.
  - AdamJacobMuller 4y ago
    You would see fluctuating voltage depending on load. Normally you should only see local load variations of maybe a volt or three (unless you're doing something with long extension cords and like living a bit dangerously). A loose/lost neutral situation can see voltage fluctuate 10s of volts. I think technically the range would be from 60V->180V, but, don't quote me on that and I'm not sure this meter can see that wide of a range.
- throwanem 4y ago
  They also make the electrical-wiring equivalent of a cable toner, which is something I've wondered about for ages. Having recently bought a house wired by an electrician who did fine work in the conduits but seems to have struggled with the command of written language required to produce legible labels in the panel, I expect to get good use out of the one I've just ordered. (The outlet tester/tone generator in this kit doesn't show voltage, but multimeters are cheap these days and much more generally useful.) https://www.acmetools.com/klein-tools-digital-circuit-breaker-finder-et310/092644692406.html https://www.acmetools.com/klein-tools-digital-circuit-breake...

by js2 4y ago

jcalvinowens 4y ago

No it wouldn't. The neutral was cut, that tool can't reliably identify that problem. The tester will see a voltage that depends on the other loads in the house, which might be lower or higher than normal. Your tester would also still show the outlet as grounded, because it just checks for continuity from neutral to ground at the outlet, which exists even when the utility neutral is broken because of the neutral-ground bond at the service entrance. A common misconception is that the neutral-ground bond at the service entrance is what makes the system grounded. That is not true: it is the neutral-ground bond at the transformer that makes the system grounded. If you break the utility neutral wire, the ground (earth) is too bad a conductor to work in its place, even if the transformer and panel both have intact neutral-ground bonds.

js2 4y ago
You're right. That makes sense.
mindslight 4y ago
> A common misconception is that the neutral-ground bond at the service entrance is what makes the system grounded. That is not true: it is the neutral-ground bond at the transformer that makes the system grounded Er, what? It's any/all of the neutral-ground bonds that make the system grounded. The more ground connections, the more redundancy and lower impedance. ... which is probably why the plumber didn't worry too much about disrupting the building's ground connection. If everything else is wired up right it's not going to be that big of a deal - perhaps a few volts on the building's grounding conductor versus actual earth, due to the current on the service neutral.
- jnsaff2 4y ago
  Yeah. Here in EU I get 3 phase cables only coming from the transformer. Then at my house a grounding rod is used to give combined Protective Earth and Neutral (TN-C). At my house main panel they are split into PE and N (TN-S). They are never connected house side and I now have combo RCD’s so each automatic fuse is also an RCD. EDIT: I was wrong, there are 4 conductors coming from the transformer, 3 phases and a Neutral. Phase-Neutral 230V and Phase-Phase 400V. Grounding rod connects to the Neutral and 4 conductors come to the main electricity cabinet. There Neutral and PE are split.
  - mindslight 4y ago
    It sounds like the branch circuits must be wired delta (phase to phase, rather than phase to neutral). What's the neutral actually do? Or does your earth have low enough impedance that you can get away with low power loads returning unbalanced phase current through the earth?
    - jnsaff2 4y ago
      Earth is used as return path for any current. Someone described it as an endless source/sink for electrons. I don’t have any delta loads in my house, but I could of course if I needed to.
      - mindslight 4y ago
        That's odd, and I can only think you must live in an area where the earth is conductive enough to carry significant current (or are the cables coming from the transformer inside a metal conduit?) The earth is nothing like "an endless source/sink for electrons". Rather, electricity always flows in a complete loop (circuit), and the current flow is somehow getting back to the transformer to complete that circuit.
        derefr 4y ago
        All you need to conduct long distances through the earth is a big buried plate to spread the current across. See e.g. https://en.m.wikipedia.org/wiki/Earth-return_telegraph https://en.m.wikipedia.org/wiki/Earth-return_telegraph. > The earth is nothing like "an endless source/sink for electrons" It’s a bounded sink for electrons, though — i.e. it has capacitance — insofar as a positive ionization required for a static discharge (lightning) built up in the earth can be “spent” by grounding voltage into it. You can think of the earth as a constantly-recharging (but sometimes rapidly discharged) anti-supercapacitor. Just like the atmosphere is a constantly recharging (but sometimes rapidly discharged) regular supercapacitor. Ignoring that, though, what people usually mean by this is that the combined neutrals of the entire power grid are on the other end of any dumping of current you’re doing into ground. It’s not just your local neighbourhood transformer; if your transformer’s resistivity increased too much due to the added ground-return current, then the rest of the current could find another path to some other, further-afield transformer, or multiple such. Or maybe even the local power plant. Or some unrelated grid-connected power plant. Or—dangerously—a power plant connected to a physically proximate but electrically disconnected grid… which is in part what makes power-factor wobble around so much in black-start grid power stations.

AdamJacobMuller 4y ago

Even if it wouldn't have detected this problem, that Klein tool detects a lot of problems which don't immediately cause weird issues. E.g. open grounds, flipped ground/neutral, flipped hot/neutral. Lots of things which work perfectly fine, until they don't. The GFCI tester on them is great too. Klein makes a marginally more expensive version ($20) which does show voltage and you could have seen the symptoms of this particular problem. https://www.amazon.com/Receptacle-Electrical-Klein-Tools-RT250/dp/B08QW7K1JJ https://www.amazon.com/Receptacle-Electrical-Klein-Tools-RT2...

electriclove 4y ago
How would the symptoms manifest on this tester? Would it show a different number?
- NavinF 4y ago
  Yeah and that number (voltage on one leg) would increase well above 120V when you place a large load on the other leg using other devices like space heaters.
- AdamJacobMuller 4y ago
  You would see fluctuating voltage depending on load. Normally you should only see local load variations of maybe a volt or three (unless you're doing something with long extension cords and like living a bit dangerously). A loose/lost neutral situation can see voltage fluctuate 10s of volts. I think technically the range would be from 60V->180V, but, don't quote me on that and I'm not sure this meter can see that wide of a range.
throwanem 4y ago
They also make the electrical-wiring equivalent of a cable toner, which is something I've wondered about for ages. Having recently bought a house wired by an electrician who did fine work in the conduits but seems to have struggled with the command of written language required to produce legible labels in the panel, I expect to get good use out of the one I've just ordered. (The outlet tester/tone generator in this kit doesn't show voltage, but multimeters are cheap these days and much more generally useful.) https://www.acmetools.com/klein-tools-digital-circuit-breaker-finder-et310/092644692406.html https://www.acmetools.com/klein-tools-digital-circuit-breake...