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adaptor and the grounding cable

We just moved into an old house. We found a 2-to-3 prong adaptor with a coiled wire going through the window frame, and connected to a metal pipe outside. See picture.

I tested it with a LED socket tester, it says everything is correct and grounded. But it looks sketchy to me, I don't understand why the coils, or if this is is really going to be safe. What do you think?

As you can see on the pic, I installed a GFCI adaptor (yellow thing) on top of the 2-to-3 prong adaptor. I'd like to believe that with that, even if the sketchy grounding wire were to not do its job, the GFCI would trip and save the day. Would also love confirmation of that please.

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  • Not real sure about UL and what other paper documents would say, but to be safe and protected from gradient voltages the ground wire from the adapter would need to be connected to the same grounding electrode system that serves the electrical "Service". – NoSparksPlease Jan 5 at 5:09
  • Is that an extension cord coming out of the wall? GFCI or not that is not safe. If the pipe is at the entrance to the house it should be bonded and then it would comply with code. As the electrode system is the first 5’ not enough info to know but that part may be code compliant. #6 wire doesn't have to be protected but it should be attached to the structure. – Ed Beal Jan 5 at 15:35
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I don't know if it's "safe" or not... that's a word that means different things to different people.

But I'd say your wiring is a hack, and should be fixed. The "grounding wire" is supposed to connect back to the source of the power, not just "the ground".

Despite popular notions, electricity wants to return to its source, not the ground. The ground wire is there to attach anything with a metal exterior to a low resistance path back to the electrical source so if a live wire touches it, the breaker will trip instead of remaining live and potentially electrocuting someone.

Does that pipe outside connect back to your panel (thus to the neutral wire coming into your house)? I don't know... maybe? Maybe it is today, but maybe tomorrow you hire a plumber and that replace a section of pipe with PEX.

Your GFCI hookup likely makes things a bit safer, but it seems a bit impermanent, and hackish to me. Someone staying at your house could easily remove it because it's in the way, etc, and then you're back to having a strange, possibly false ground wire. You should likely replace your setup with a GFCI outlet, and remove the weird hack wire. The NEC code allows you to do this.

Alternatively, you could just disconnect the whole weird contraption, and have a two prong outlet with no ground. You couldn't hook up any three prong equipment to it, but a lot of electrical equipment is 2 prong only, so this isn't terrible. This option is likely a bit more dangerous than putting in a GFCI, but is a bit safer than the weird hack you have now.

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  • Steve see 250.130.C , not enough info to know at this point , yes it looks like a hack but the heavy copper connected to a water pipe at the entrance of a house would comply with 250.50 , also use caution when linking old documents for example in October of 14 my state was just adopting the 14 code many states were still on the 11 code and earlier, for example today I checked the 2020 NEC adoption map and only 6 states have adopted it and we are in 2021. The approval to run a separate grounding conductor was just recently approved by the NEC. – Ed Beal Jan 5 at 15:51
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    @EdBeal Maybe it might comply, but it's still an ugly hack and deserves to be fixed. I'm talking about what's actually safe, or best practice, not code. We have no idea what code the guy is under, but I CAN tell you what's safer, and IMO the permanent GFCI is safer than some unknown hack of a grounding wire out the window. – Steve Sether Jan 5 at 19:28
  • The GFCI’s in use in the us don’t use the ground so ground hack or not it would not matter here for listed devices. – Ed Beal Jan 5 at 19:38
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I think it is safe. Who ever installed it didn't cut the ground wire so they could possibly use it somewhere else: This is from the NY residential code:

E3508.1.1 Metal Underground Water Pipe

A metal underground water pipe that is in direct contact with the earth for 10 feet (3048 mm) or more, including any well casing effectively bonded to the pipe and that is electrically continuous, or made electrically continuous by bonding around insulating joints or insulating pipe to the points of connection of the grounding electrode conductor and the bonding conductors, shall be considered as a grounding electrode (see Section E3508.1). Interior metal water piping located more than 5 feet (1524 mm) from the entrance to the building shall not be used as part of the grounding electrode system or as a conductor to interconnect electrodes that are part of the grounding electrode system.

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  • Running a wire to the ground (a rod or a pipe in the ground) doesn’t accomplish anything by itself. It must also be bonded to neutral at the main panel to function properly. – nobody Jan 5 at 13:28
  • Ground is ground. Are you saying New York's code is wrong? There is something called a 'ground loop' but that is only problematic in audio applications. – Steve Wellens Jan 5 at 14:38
  • Ground is NOT ground. If you drive a grounding rod into the earth, and hook up live wire to it will it trip the breaker? I assure you that it won't. That's the point of the safety ground is to trip the breaker. – Steve Sether Jan 5 at 14:55
  • Let’s just use the NEC since so many internet electricians want to down vote. 250.130.C.1 Any accessible point on the grounding electrode system as described in 250.50 , For all you internet electricians code has a picture exhibit 250.22 , oh for others that think it is only at the electrode or 5’ read 250.130.C.2. Any point on the GEC, so there is not enough information to know if that ground is at the electrode or not. But as far as safe that looks like a cord coming out of the wall and that would violate code. – Ed Beal Jan 5 at 15:51
  • The point of safety grounds is to prevent electric shock, if they also trip the breaker thats a good thing. suppose the neutral of your toaster breaks loose and comes in contact with the case... a non-bonded earth spike will neither make the appliance safe or trip the breaker. – Jasen Jan 5 at 20:10

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