FAQ: Neutral and Ground Wires are not Interchangeable

Again, the idea isn’t what will work in a pinch. The idea is what best practice will result in less house fires.


I think you win the thread :smiley:

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“In a pinch” isn’t going to apply to replacing a light switch. Neither a judge nor an insurance company is going to accept that as a justifiable reason for intentionally violating code.

If somebody was trapped in an outbuilding and you had to complete a circuit in order to rescue them before a hurricane arrived, OK, A field tech might have to do some “in a pinch” work because of the time constraints.

We’re talking about replacing a light switch. It’s going to be used every day for years. It’s likely be passed on to new people. Other work is going to be done connected to the electrical system.

“All the other ways to do this require spending more money then I want to” just isn’t the same as “in a pinch” when it comes to safety issues.

So I’m just not seeing it.



I know we all love home automation, hell we love it so much we spend our free time here talking with people we’ve never met about turning on lights. But hopefully we can all set that “passion” aside and remember that safety must be priority number 1 when we are doing any sort of electrical work. Yeah sure combining the neutral and ground wires will get the lights to turn on, but by doing so puts every person who steps foot into your house at the risk or injury or death.

If we decide that automation is a necessity, then we must be willing to fork over the money to do it correctly.


When you put it that way you make me feel bad about myself. :wink:

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Hey, I talk about the garage door too!

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Don’t dumb it down too much, we talk about turning off lights as well.


@JDRoberts, good post.

This should be a sticky post so everyone sees it.

I found this by accident.
@JDRoberts, I’m almost astonished this needed an explanation…

I wish you could just display this picture instead of a thread title.


Another rookie question here. Using a voltmeter, I measure between the two slots of a receptacle in the garage and get a 112V reading, as expected. Next, I measure between the ground hole and the hot wire slot and get no voltage, which is also as expected.

But then 15 feet away, outside the garage wall, the neutral wire is connected to the same bus as the ground wire. Why did I get two different readings if the neutral and ground share the same connection?

Guys I ended up in here just like everybody else as I’m trying to install new smart switch but I don’t have neutral wire at the box there, but, at a box few inches away there is a neutral wire from another circuit. My question is: can I connect to that neutral wire? Based on the fact that all neutral wires connect at a bus eventually, why can’t I connect to a neutral wire from another circuit.

I appreciate your comments and replies.

Unfortunately, the short answer is no.

The long answer is in the following thread, including the NEC code references and the problems you can encounter:

Thanks a lot JD,
I’ll move away from the smart switch option on this light.

There are quite a few options now for smart switches that do not require a neutral. See the FAQ:

FAQ: SmartThings-Compatible Switches that Don’t Require Neutral (US, 2019)

You can always have an electrician pull a neutral for you too.

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I imagine this would cost a lot. The light bracket is not far from the switch I tried to fish a wire myself but I couldn’t, conduit is pretty tight, other cables are in there blocking the way and I imagine there should be few turning points along the way. I tried to find some hints on YouTube but not much luck!

Did you try just pushing the wire or did you use fish tape or fish poles? You will need tape/poles where you push it through, connect wire to end and pull it back if it’s that tight. If there is enough room sometimes you can push the wire along with the tape/pole. They sell these at the big box stores or online and come in different lengths.

Make a few pumpkin cuts on your drywall ( 3 sides so you can use it as a flap, way easier to patch ) by the studs, drill some holes and pigtail wire from the next outlet. There are plenty of youtube videos out there.

Yes… You are correct. The fact is the neutral at the switch (the one being created with the use of the “bond” wire) is for the switch solely, not the circuit. Everyone here has there pants in a knot over code (I’m an electrician) and I can tell you that using the “BOND” wire for this purpose is completely okay (funny everyone who’s an expert here has actually failed to use the correct word. It’s called a bond wire. A ground wire or simply a “ground” is actually what physically goes into the ground from the panel… or the “ground” bus. )

So… The switch actually draws very little current, not enough to have cause any damage or risk.

btw… I just used my bond as a “neutral” for my wifi dead end 3 way switch. :slight_smile: I’m also a licensed electrician!

I realize this is an old post, but for the benefit of anyone else with a similar issue, I would like to comment.

Daniel, it sounds like your outlet has the hot and neutral wires reversed, or if that’s not the case, then your ground wire may not be connected. You said you measured between the ground hole and the hot wire slot (smaller slot) and got no voltage, which is what you expected. Why would you expect no voltage? As you pointed out, the ground wire and neutral wire both connect to the same grounding bar inside the electrical panel, so they both should produce the same voltage reading when paired with the hot wire. There is definitely something not right if you get no voltage reading across hot and ground.