# If my green ground wire is carrying current, how would I know? **URL:** \ **Category:** Factual Questions\ **Created:** [December 3, 2025, 12:13am UTC](https://boards.straightdope.com/t/if-my-green-ground-wire-is-carrying-current-how-would-i-know/1025346 "2025-12-03T00:13:19Z")\ **Posts on this page:** 14\ **Page:** 2
**Author:** ![Melbourne](https://avatars.discourse-cdn.com/v4/letter/m/b5e925/32.png) [@Melbourne](https://boards.straightdope.com/u/Melbourne)\ **Post date:** [December 4, 2025, 11:33pm UTC](https://boards.straightdope.com/t/if-my-green-ground-wire-is-carrying-current-how-would-i-know/1025346/21 "2025-12-04T23:33:33Z")
> [@Nars\_Glinley](#): > > My house is around 15 years old and about a third of my breakers are GFCI and are for the bedrooms and living room. All kitchen and bathroom breakers are non-GFCI but each circuit has at least one (and maybe only one) GFCI receptacle. AIUI, one receptacle protects the entire circuit. Not really. Typical GFI sockets compared the active and neutral current through the socket, and disconnected the socket on mismatch. For bathroom and kitchen, the whole point was that some appliances had very poor ground isolation, so you wanted to put them on non-GFI outlets, and you didn’t want them to disconnect other, GFI protected, outlets. Given that you have non-GFI outlets, I’m surprised that you didn’t also include “laundry” as another place with non-GFI outlets. Given that you wrote “15 years”, I’m surprised you have any non-GFI outlets. Around here, the problem of Ground Fault leakage in water heaters, stoves, and small electric appliances was pretty much gone by 30 years ago. Solar Panel system are, by default, floating. Modern regulations have moved towards “single fault detection”, just as a general safety measure. As discussed above, it’s the _second_ ground fault that is easy to detect, and can kill you. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [December 5, 2025, 12:17am UTC](https://boards.straightdope.com/t/if-my-green-ground-wire-is-carrying-current-how-would-i-know/1025346/22 "2025-12-05T00:17:21Z")
“Click" ---
**Author:** ![Nars\_Glinley](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/nars_glinley/32/8177_2.png) [@Nars\_Glinley](https://boards.straightdope.com/u/Nars_Glinley)\ **Post date:** [December 5, 2025, 4:06am UTC](https://boards.straightdope.com/t/if-my-green-ground-wire-is-carrying-current-how-would-i-know/1025346/23 "2025-12-05T04:06:17Z")
> [@Melbourne](#): > > Given that you have non-GFI outlets, I’m surprised that you didn’t also include “laundry” as another place with non-GFI outlets. Given that you wrote “15 years”, I’m surprised you have any non-GFI outlets. Around here, the problem of Ground Fault leakage in water heaters, stoves, and small electric appliances was pretty much gone by 30 years ago. It didn’t occur to me and now that I have checked, the washing machine isn’t covered by GFI at the outlet or the breaker. Seems kind of weird since the water supply is about 6 inches from the receptacle. ETA: Looks like the code in the US changed in 2020. I bought the house in 2019. ---
**Author:** ![md-2000](https://avatars.discourse-cdn.com/v4/letter/m/9d8465/32.png) [@md-2000](https://boards.straightdope.com/u/md-2000)\ **Post date:** [December 6, 2025, 2:05am UTC](https://boards.straightdope.com/t/if-my-green-ground-wire-is-carrying-current-how-would-i-know/1025346/24 "2025-12-06T02:05:22Z")
> [@engineer\_comp\_geek](#): > > It’s entirely possible that this type of fault might not burn anything out, and there wouldn’t be any “fireworks” like you’d get if the hot wire shorted to the case since the neutral and the safety ground are both at essentially the same electrical potential. The ground wire, unless it has unexpected resistance, is at ground - 0V. if there’s current, the the source of the current, where the short (or whatever) is either effectively regulates the amount of current to smaller amount, or that point will get really hot shortly (sorrry). ---
**Author:** ![Marvin\_the\_Martian](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/marvin_the_martian/32/2898_2.png) [@Marvin\_the\_Martian](https://boards.straightdope.com/u/Marvin_the_Martian)\ **Post date:** [December 6, 2025, 3:21pm UTC](https://boards.straightdope.com/t/if-my-green-ground-wire-is-carrying-current-how-would-i-know/1025346/25 "2025-12-06T15:21:09Z")
No. @engineer_comp_geek is talking about a neutral shorted to ground. Both are nominally at the same 0V potential and are in fact tied together at the main panel. If they are shorted, the current that normally flows through the neutral wire will flow through both the neutral wire and the ground wire, split based on the relative resistances of the neutral and ground paths. ---
**Author:** ![Ancient\_Nerd](https://avatars.discourse-cdn.com/v4/letter/a/ed655f/32.png) [@Ancient\_Nerd](https://boards.straightdope.com/u/Ancient_Nerd)\ **Post date:** [December 7, 2025, 12:51am UTC](https://boards.straightdope.com/t/if-my-green-ground-wire-is-carrying-current-how-would-i-know/1025346/26 "2025-12-07T00:51:33Z")
> [@Marvin\_the\_Martian](#): > > Both are nominally at the same 0V potential and are in fact tied together at the main panel. Neutral is tied to a stake driven into the dirt at the base of the utility pole holding the transformer. Ground is typically connected to something like a cold water pipe going into the dirt near the service entrance. They both go to an earth ground but generally several hundred feet apart. That neutral line carries current so there will also be some IR voltage drop. One would expect a small difference in voltage between the two. ---
**Author:** ![Melbourne](https://avatars.discourse-cdn.com/v4/letter/m/b5e925/32.png) [@Melbourne](https://boards.straightdope.com/u/Melbourne)\ **Post date:** [December 7, 2025, 12:54am UTC](https://boards.straightdope.com/t/if-my-green-ground-wire-is-carrying-current-how-would-i-know/1025346/27 "2025-12-07T00:54:51Z")
> [@Ancient\_Nerd](#): > > Neutral is tied to a stake driven into the dirt at the base of the utility pole holding the transformer. Note that this, like much else in the electricity system, is specific to your country (in this case, the USA). ---
**Author:** ![Ancient\_Nerd](https://avatars.discourse-cdn.com/v4/letter/a/ed655f/32.png) [@Ancient\_Nerd](https://boards.straightdope.com/u/Ancient_Nerd)\ **Post date:** [December 7, 2025, 1:08am UTC](https://boards.straightdope.com/t/if-my-green-ground-wire-is-carrying-current-how-would-i-know/1025346/28 "2025-12-07T01:08:47Z")
> [@Melbourne](#): > > Note that this, like much else in the electricity system, is specific to your country (in this case, the USA). There may be different ways to do it but, it seems like everyone would need to avoid ground loops. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [December 7, 2025, 1:12am UTC](https://boards.straightdope.com/t/if-my-green-ground-wire-is-carrying-current-how-would-i-know/1025346/29 "2025-12-07T01:12:58Z")
A small voltage difference, sure, but only a small one, and not an enforced voltage difference, so if something does short them together, a current will flow very briefly until they’re at exactly the same again, and then they’ll stay the same (at least at that spot and its close vicinity). ---
**Author:** ![Melbourne](https://avatars.discourse-cdn.com/v4/letter/m/b5e925/32.png) [@Melbourne](https://boards.straightdope.com/u/Melbourne)\ **Post date:** [December 7, 2025, 1:15am UTC](https://boards.straightdope.com/t/if-my-green-ground-wire-is-carrying-current-how-would-i-know/1025346/30 "2025-12-07T01:15:05Z")
If you aren’t using American-style distribution transformers, there is not even an isolated neutral to ground at the distribution transformer. Of course, if you aren’t using American-style 120V services, there aren’t as many transformers. Earthing systems are part of the distinctive differences between different national electricity systems, with long standing debates about the relative advantages and disadvantages, and as much institutional inertia as driving-on-the-left vs on-the-right. ---
**Author:** ![Ancient\_Nerd](https://avatars.discourse-cdn.com/v4/letter/a/ed655f/32.png) [@Ancient\_Nerd](https://boards.straightdope.com/u/Ancient_Nerd)\ **Post date:** [December 7, 2025, 1:32am UTC](https://boards.straightdope.com/t/if-my-green-ground-wire-is-carrying-current-how-would-i-know/1025346/31 "2025-12-07T01:32:37Z")
> [@Chronos](#): > > a current will flow very briefly until they’re at exactly the same again, and then they’ll stay the same Ground loops often oscillate. The current doesn’t stop when the voltages are the same, it overshoots and corrects over and over again. ---
**Author:** ![Ancient\_Nerd](https://avatars.discourse-cdn.com/v4/letter/a/ed655f/32.png) [@Ancient\_Nerd](https://boards.straightdope.com/u/Ancient_Nerd)\ **Post date:** [December 7, 2025, 1:36am UTC](https://boards.straightdope.com/t/if-my-green-ground-wire-is-carrying-current-how-would-i-know/1025346/32 "2025-12-07T01:36:03Z")
> [@Melbourne](#): > > there is not even an isolated neutral to ground at the distribution transformer. That seems a little scary. If the secondary side can just float, it could get to thousands of volts. How do they do it over there? ---
**Author:** ![Marvin\_the\_Martian](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/marvin_the_martian/32/2898_2.png) [@Marvin\_the\_Martian](https://boards.straightdope.com/u/Marvin_the_Martian)\ **Post date:** [December 7, 2025, 1:53am UTC](https://boards.straightdope.com/t/if-my-green-ground-wire-is-carrying-current-how-would-i-know/1025346/33 "2025-12-07T01:53:09Z")
> [@Ancient\_Nerd](#): > > Neutral is tied to a stake driven into the dirt at the base of the utility pole holding the transformer. Ground is typically connected to something like a cold water pipe going into the dirt near the service entrance. Neutral and safety ground are connected together at the main panel, in the US at least. If you look in the main panel (not a subpanel) you will see both the typically bare safety ground wires and the typically white neutral wires connected to the same ground bar. Neutral and safety ground are also physically connected to ground as you describe, but past the main panel. ---
**Author:** ![Melbourne](https://avatars.discourse-cdn.com/v4/letter/m/b5e925/32.png) [@Melbourne](https://boards.straightdope.com/u/Melbourne)\ **Post date:** [December 7, 2025, 2:18am UTC](https://boards.straightdope.com/t/if-my-green-ground-wire-is-carrying-current-how-would-i-know/1025346/34 "2025-12-07T02:18:15Z")
Our systems are earthed. Historically the bonding position and earth points are different in different systems. The exact nature of earthing systems in different countries is converging, but still represents historical differences. For example I have a substation about 1/4 mile away, not a utility pole several hundred feet away. [Previous page](https://boards.straightdope.com/t/if-my-green-ground-wire-is-carrying-current-how-would-i-know/1025346.md?page=1)