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I have a 3 wire outlet with the entrances for hot, neutral and ground. But I know that the ground entrance is not really grounded, so in effect useless. Now, since the neutral is grounded, could I connect the ground entrance with the neutral therefore grounding the ground? What would be the problem with that?

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If you don't have an EARTH wire DO NOT BRIDGE NEUTRAL + EARTH! This is potentially lethal as AC NEUTRAL is -220VOLTS! Earth is used in conjunction with LIGHTNING ARRESTORS and SHORT CIRCUITS prevention mechanisms! If you want earth- you need to UPGRADE your entire electrical system. – ppumkin Oct 3 '11 at 11:07
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@ppumkin, neutral to ground should be 0 volts. If it's not, then it's not a neutral. For 220v circuits in the US, you have two out of phase hot connections at 110v each in addition to a neutral. That said, any issue anywhere in the wiring could result in an energized ground. – BMitch♦ Oct 3 '11 at 12:24
The Definition of Alternating Current illustrates a Sine wave of t(time) in + then the same span in - (50/60hz) . Direct Current is always equal to or greater than 0! The very reason Negative AC is lethal if connected in the incorrect manner! eg. Never use AC negative as a radio antenna! Besides, Neutral in AC is only for distinguishing reasons as in theory there is never a + or - pole in AC(by definition Alternating!) Every wonder why a AC Bulb can be wired in "reverse" polarity and work but not in DC. – ppumkin Oct 3 '11 at 14:48
@ppumkin google "Neutral Wire Facts and Mythology". There is a difference between neutral and hot even in AC circuits. One of the differences is that the neutral is grounded, therefore you shouldn't receive a shock if you touch neutral. Also notice that some plugs are asymmetrical so that you can't reverse the neutral with hot(the reason for this is explained in the document at the beginning). – Mr. Roland Oct 3 '11 at 17:48
You need to indicate what country (and possible what state) you're in as voltages and building codes come into play here, too. – staticsan Oct 3 '11 at 23:56
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5 Answers

up vote -4 down vote

There is no such thing as neutral in electricity. That would mean not being used. the neutral and ground are both ground paths. The issue is that the ground wire is usually used to dissipate static. while it should work and cause no problems I would not want to trust it with a pc or power tool. Both wires run to the exact same bars on a breaker box so in theory itll be ok but now you'd be trying to get rid of static down a line trying to deal with power from the supply side.

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up vote -3 down vote

nuetral should be connected to ground so that any appliances touch the hot wire you will not be electricuted because even one hot wire touch any appliances and your stepping on the ground or holding any metal and touch that appliances you will be electricuted and that metal your touching will serves as ground.

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This is just wrong. Don't do this. Neutral and ground should ONLY be bonded at the main panel. – Steven Nov 3 '12 at 15:37
up vote 3 down vote

The ground is supposed to provide an alternate path to ground, in case the neutral wire doesn't do a good enough job. I don't know of any cases where the neutral would be compromised while a ground wire in the same sheath isn't -- except where someone mucked with the wiring.

If you only have two wires, that tells me you're in an older house. So it's possible (likely!) that a former homeowner did something wrong, like put a switch in the neutral, or reversed polarity. If you know all of the devices on a particular circuit, you can do the detective work to ensure that this hasn't happened.

Or you can run a separate ground wire to a water pipe. This does meet code in the US (at least as-of 1999, which is what my electrical handbook is based on), and it's what I did for my home office (I wasn't happy having computers on ungrounded circuits). To completely meet code, you need to ensure that the cold water pipe has a conductive strap to bypass the water meter. And you need to use a wire that is the same gauge as that used for the circuit (14ga for a 15 amp circuit).

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Your answer is not entirely correct. the "earth" wire detects leaks on applications that could be fatal to the user. EG electric boiler element burns out and the boiler becomes a "live" box- Earth detects this leakage and cuts the MAIN power to the DB(by electrical code) In the case of alternative route a SURGE PROTECTOR/LIGHTNING ARRESTER NEEDS TO BE INSTALLED IN CONJUNCTION WITH EARTH LEAKAGE CIRCUIT! to server as an alternative over current route. – ppumkin Oct 3 '11 at 15:16
@ppumkin - I see that you're from the UK. Based on the wording of the question I assumed (perhaps incorrectly) that the OP was from the US. I'm not familiar with the European system, but based on your comments I'll assume that it's the same as the US 240V system. The US 120V system, however, does have a "hot" and "neutral" wire, and the neutral is wired to a grounding strap at the box. Perhaps there needs to be separate tags for "electrical-us" and "electrical-uk". – kdgregory Oct 3 '11 at 16:08
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Electricity is the same all over the world.. standards are the problem though. It is most likely that the negative that is wired into a grounding strap must be connected to a rod that goes in to the earth somewhere outside. That is an old way of doing things and works well for lighting protection. but has some problem with appliance / user protection. I was actually certified in South Africa and understand the importance of lightning protection- but all new home builds(in ZA) do not have long rods into the earth any more and lightning poles are optional. – ppumkin Oct 3 '11 at 16:15
up vote 4 down vote

I'm not in the US. Where I live this (called "combined neutral and protective earth wire") is only allowed in non-domestic power distribution.

This setup has one major problem: if phase and neutral are swapped (for example, you alter wiring in the box next to the power meter and swap wires) phase is now supplied onto the grounding contact as well and that's asking for trouble.

So you can try do that, it's likely better than no grounding, but it's likely not up to code, and it is hazardous in that if wiring is altered you can have phase on the grounding contact and hence on appliance case.

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+1, great point. I believe if you swap the hot in this configuration, a standard outlet tester will indicate the error. – BMitch♦ Oct 3 '11 at 11:09
Unless I'm missing something, I think the "better than no grounding" point here is key. Many people faced with a two-prong outlet will use an adapter that leaves them with an open ground. If an appliance plugged in there has a hot-ground short, the appliance exterior will become hot rather than tripping the breaker. If you wire ground to neutral such a faulty appliance will at least trip the breaker. Given that faulty appliances seem to me to be likely more common than a break in the neutral wire in the wall, it seems like ground-to-neutral is at least an improvement over open ground. – Carl Meyer Nov 4 '11 at 19:59
up vote 6 down vote

I don't believe this is up to code, but it will pass the test from a standard outlet tester. The problem I see is if any device plugged into the outlet comes into contact with a ground (e.g. water) and that path is more efficient than going all the way back on the neutral wire through the house wiring, then hot current going through any appliance and onto the neutral would come out the ground and possibly electrocute anyone in that path.

That said, I've seen this implemented and have lived in a home where this was done without dying, or even getting shocked. But the fact that the electrician that used this trick was missing several fingers should give you pause.

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"that path is more efficient than going all the way back on the neutral wire through the house wiring," Wouldn't this problem also happen if you had a correct outlet with a ground cable going through the house wiring? – Mr. Roland Oct 3 '11 at 18:02
@Mr.Roland, nope, consider if the neutral connection failed between the outlet and breaker. If you had a proper ground, nothing would happen since there is no path from hot to the ground. But with the neutral-ground connection, current would go from hot, to the neutral in the outlet, and back out the ground. If the device has a metal exterior, the entire surface is now energized and waiting to electrocute you. – BMitch♦ Oct 3 '11 at 20:14

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