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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Bridging the neutral and ground at the outlet is against code. This is called a Bootleg ground. You have a few different options to bring this up to code (corresponding to the NEC electrical code):
- Replace the outlet with a GFCI outlet, and leave the outlet's ground unconnected. This is minimally dangerous, the risk is if you get your body somewhere in between the hot and neutral.... but it'll protect you if current tries to flow between the outlet, and devices on another outlet (or the ground).
- Add an additional ground wire. The wire must be of the proper gauge, and go to a "grounding electrode", or your main circuit panel. There are a few other details that you'd need to follow. See NEC 250.130(C) for details.
- Rerun the wiring for the outlet with three-conductor cable/conduit.
- Replace the outlet with a 2-prong outlet.
Keep in mind that the ground and neutral should be connected together at your house's service entrance, and nowhere else.
The "ground" connector is often connected to the chassis of electric equipment, for example the metal case of your oven, lamp, etc.... One danger is that the neutral is not really at the same potential as the ground. The neutral wiring from your device has some non-zero resistance. The electric current flowing through your device also flows through the neutral wire. The current flowing through your neutral causes the voltage of the neutral to increase (based on Ohm's law, voltage = current * resistance), which can cause your neutral to be a few volts above ground. So, if you have a properly grounded device, next to a device connected to your bootlegged ground, you can shock yourself by touching the two cases since they will be at different potentials.
A second problem with connecting the ground to the neutral happens if your neutral wire breaks between the outlet and your service entrance. If the neutral breaks, then plugged in devices will cause the neutral to approach the "hot" voltage. Given a ground to neutral connection, this will cause the chassis of your device to be at the "hot" voltage, which is very dangerous.
Pigrew
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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.
BMitch
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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.
sharptooth
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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).
kdgregory
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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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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.
