Bare ground wires are not current carrying conductors. If they were every device attached to them (boxes, fixtures, appliances) would be electrically hot. You can be killed from touching a neutral conductor. If you tied ground and neutral at the receptacle every ground would now carry current back to the panel.
The safe way to convert a 2 prong to a grounded 3 prong is to re-wire the cc't using a separate ground wire back to the panel. In some instances you may be able to ground the recept to a cold water pipe that has a complete and continuous copper connection to the street side of your water meter.

bigbird1: You can be killed from touching a neutral conductor.

can you explain to me how I took one neutral (of a pair of 500mcm conductors) from the line side of the 800 amp service I am currently working with barehanded and steel tools and I am here tonight typing this?

Now, I'm not saying you can never be shocked by a neutral but if things a connected correctly there will never be more voltage (to ground) on a neutral than the voltage drop of the circuit involved at the point you are touching it.

The idea of the GROUNDING wire is that there is a low resistance path to ground for faulting currents. That ought to be reason enough. There are a number of reasons for the low resistance path to be needed: to keep the exposed equipment at a safe potential, to provide rapid tripping of the overcurrent device, to help isolate transients, etc...

However, to answer dozer, the idea that the grounding conductor is not ever supposed to be carrying any load currents. The idea is that it is connected to the frame and other exposed parts of equipment. If a neutral connection fails with a separate grounding system, there is not a problem, the circuit fails to work (or subjects the devices to twice the normal voltage) but the exposed metal stays grounded. If the neutral and the grounding conductors were allowed to touch, the equipment may indeed become energized.

If some load is connected in an energized circuit and the neutral is broken/interrupted between that load and the panel, the portion of the neutral that is no longer connected to the panel will be energized at full line voltage. Such breaks/interruptions can and do occur. Connected grounds would also be energized. Tieing the neutral and any equipment ground together at any point after the main panel is potentially deadly. This question frequently is asked here and just about as often, the questioner continues to insist that the idea is a good one. Some folks ask seeking information, some ask seeking approbation.

bus_driver, the broken neutral is a good point. That's the only one so far to convince me but it's enough. I had to draw it out to grasp it, a symptom of all my electronics labs years ago. Unfortuanetly running any new wire to the outlets, even if it's just a ground line, is out of the question. Far too expensive (plaster walls in a three story house). I'd have a better chance pulling off burning the house down and getting the insurance company to pay for a new one. In lieu of that I'll just start putting in GFI's when I can. Thanks for the info.

"can you explain to me how I took one neutral (of a pair of 500mcm conductors) from the line side of the 800 amp service I am currently working with barehanded and steel tools and I am here tonight typing this?"

Sure can. Because there was no neutral fault in the cc't you were working on. Here's a common scenario for you. Some doofus wires a multi-wire shared neutral and puts the individual single breakers without tie bars far apart on the panel. Along comes the unsuspecting DIY'er. He/she flips one of the single pole breakers off, double checks the hot wire with a tic tester, gets no response, and then touches the neutral while touching anything else, and...I don't have to tell you the rest.

A neutral wire carrying current also has a voltage drop present.
This puts its voltage above the grounding conductor with no current and no drop.
Touch the neutral at the far end of a heavily loaded circuit and something grounded at the same time and you can be shocked.
If you tie the neutral and ground together i that outlet, everything plugged in will have the neutral voltage drop impressed on it.
Feel free to grasp the metal handle of a drill with sweaty hands and the frame of a grounded appliance (or even the metal switch plate).

Jcmo, don't be afraid to tackle that big guy! Rewiring old houses is a challenge in its own right. It requires patience, careful measurement, creativity, intuition, imagination, and plain dumb luck.

X-ray vision would be a real asset. What the heck's in the way THIS time? Sometimes you cut a hole in the wall and drill into what you're SURE is the stud cavity from below, but for all the you know, the two holes could be in different houses.

Rewiring (or wiring!) an old house is a series of puzzles. Solving each one is a real rush, at least to geeks like me. ;-)

bigbird1: it would make no difference what was on the line. If you read my post, I did state:-

Now, I'm not saying you can never be shocked by a neutral but if things a connected correctly there will never be more voltage (to ground) on a neutral than the voltage drop of the circuit involved at the point you are touching it.

Of course a neutral can shock if it is not connected to the neutral point and the panel. But at that point it would only be a neutral in name and color. It would not be a neutral by function because it is no longer a grounded conductor. It is in fact at that point a hot conductor.

But even that is irrelevent. I removed on neutral conductor of a paralled group. At the panel at that point, there is no voltage drop since the neut and the ground ar tied together 6 inches from the lug I removed the 1 neutral from. (for you guys that do not do larger stuff, since I had a paralled group of 500mcm, there was still one neutral connected at all time). but, regardless of that, if you touch a neut at the panel, there is no voltage present (to ground), no matter what is wrong out in the field. It has to have ground potential because it is connected at that point to the grounding conductor and GE system.

btw ronnatalie, I do this for a living. My question was more of an academic point than truly looking for an answer for me. I know why I was not and could not get shocked with what I did. As I did this, the only way I would get shocked is if lightning struck when I had hold of the neut.

btw; you guys also keep talking of only getting hit with a neut due to a MWBC losing its neut but don;t forget about 3 wire range and dryer circuits. Obviously, if the ground/neut is lost back to the panel, the frame of the appliance is then hot to ground due to the frame being connected to the ground/neut wire.

and yes brickeyee, if you notice, I did include the voltage drop situation

"But even that is irrelevent. I removed on neutral conductor of a paralled group. At the panel at that point, there is no voltage drop since the neut and the ground ar tied together 6 inches from the lug I removed the 1 neutral from. (for you guys that do not do larger stuff, since I had a paralled group of 500mcm, there was still one neutral connected at all time). but, regardless of that, if you touch a neut at the panel, there is no voltage present (to ground), no matter what is wrong out in the field. It has to have ground potential because it is connected at that point to the grounding conductor and GE system."

Then your story holds absolutely NO water.

"btw; you guys also keep talking of only getting hit with a neut due to a MWBC losing its neut but don;t forget about 3 wire range and dryer circuits. Obviously, if the ground/neut is lost back to the panel, the frame of the appliance is then hot to ground due to the frame being connected to the ground/neut wire."

Which is why the NEC outlawed this practice many years ago.

All the problems of using the groundING conductor as a power carrying wire have been pointed out.
The NEC has to cover as many situations as it can without getting even larger (and more detailed) than it is).

If you do this for a living the simple answer absent a lot more professional training (like an engineering degree) is do what the code says.
It MIGHT be possible to not have a hazard, but many NEC rules are designed to make sure a single failure does not create an immediate hazard to life.

petey ,I was simply making reference to an older 3 wire dryer or range circuit becaue there are still a lot of them out there. It results in actually, a more dangerous situation that the open neut on a MWBC.

I don;t get you "your story doesn;t hold water then" comment. Can you explain that a bit?

brick; if you were speaking to my statements, I have no idea your meaning either.

My whole input was because bigbird 1 had stated, "you can get killed by touching a neutral". I was simply stating and showing that as long as things are working correctly, that is not true. Unless there is something wrong with the system, there is not enough voltage drop to be lethal (at least basing it upon the 50 volts 3 milliamps as the lethal threshold statement I read a few years ago)

Because your whole story about touching a disconnected neutral is worthless since there was a parallel neutral still connected. The will be no current on the disconnected one since the one connected is carrying it/creating the circuit path.
If you disconnected both then you would have a story.

"My whole input was because bigbird 1 had stated, "you can get killed by touching a neutral".

I re-emphasize my point: You Can be killed. Not you WILL be killed. I already explained how, with a neutral fault. Of course in most circumstances touching any neutral is harmless. The OP wanted to know why you can't connect ground and neutral at a box.

bigbird, it is just that you simply said "you can be killed by a neutral" Using your last statements reasoning, you can be killed by a garden hose IF the situation is conducive to such an action. My point was simply, if things are working correctly, you will not be killed by a neutral.

petey; I see what you are saying but my post was in response to BB1 about getting killed by a neutral. Of course it wasn't going to hurt me. I took BB1's post exactly as written. He intended it to mean something other than exactly what was written and I did not see it as such. The demo was more simply as an example of a neut not hurting you in the simplest sense of BB1's post.

I believe we are all on the same page. Writing is a difficult medium of exchange of ideas at times. It is easy to misunderstand or misinterpret what was written.

"btw; you guys also keep talking of only getting hit with a neut due to a MWBC losing its neut but don;t forget about 3 wire range and dryer circuits. Obviously, if the ground/neut is lost back to the panel, the frame of the appliance is then hot to ground due to the frame being connected to the ground/neut wire. "

range and dryer circuits ARE multi-wire branch circuits, so you just repeated the same situation they did.

jmorrow:range and dryer circuits ARE multi-wire branch circuits, so you just repeated the same situation they did.
===========

yes, of course a circuit of this type is a MWBC. Obviously this MWBC is a bit different than what was being spoken of. This MWBC is required to have a 2pole breaker. The typical MWBC being talked of only requires such when the seperate circuits feed a device on the same yoke. A dryer circuit is a 120/240 rated circuit where typical MWBC are simply 2 (or 3) 120 volt circuits with a common neutral.

just simply did not see the need to go into that great of detail as it was a side comment and not meaning to alter what was already given.

My original intent was to get BB1 to expand on his statement of "you can get killed from touching a neutral conductor" Obviously that can be correct but in a normal situation, it is not but I suspected he undertood this. Don;t know if the OP did and thought it should be expanded upon to make it clear to all reading. I would rather of him flesh out his own statement. I guess posting my situation as an acedemic question was a bit misleading. Sorry if it got all you guys in the wrong frame of mind. i was not intending upon this being a bash session.

So can all of you (us) allow this to go back to saving the fire department and EMT;s from having to work and remove some of the animosity I may have brought out of you?

jmorrow; I did apologize for misreading your post and making the statement I did. I'm not going any further than that. If you want to ride my butt, you'll have to get in line. My boss has been on it and won;t get off. (you will simply have to picture it since we don't have those options on this forum). Your tirade was bit of an over zealous response to a mistake so give it a rest would ya?

Minnesota Wisconsin Baptist Convention

I yahooed (don,t have google) MWBC and this is what I got, is that the correct meaning?

You don't have Google??? Huh?

Multi-Wire Branch Circuit

Thank you.

I used to use Google but went to DSL with ATT Yahoo and it does the same as Google so I've never needed to put a Google task bar in.

To answer OP's question: When Electricity returns to your service panel on the neutral it has two choices: 80mph highway along the POCO's neutral or 20mph dirt road on, say, the #10 ground in the hot water heater circuit. Even though the #10 and the neutral are connected at the panel, electricity will "choose" the path of least resistance along the POCO neutral to complete the circuit. Now, if you were to use a neutral to GROUND an outlet, if something goes wrong, you could become the 80mph highway and the breaker would never trip because what it takes to kill a human being wouldn't even register as a nightlight.

Ok, back to a more elementary question...

A friend has a old house that we want to modify the wiring in the attic some. The house was built in 1917 I think, in-wall wiring is thick (~1/4") single rubber coated wires ran around glass insulators. No grounds, no conduit, etc. At some previous time a breaker panel has been replaced and another one added, some newer wiring is romex-ish, but I have not looked to see what they connected the ground wire to on those circuits, as I highly doubt those new wires run all the way to the panel. Nothing I have found so far was done to any sort of code, stranded wires soldered to 14-gauge old copper things and wrapped in electrical tape and stuffed in a wall (no boxes for anything)...

Sooo...if you do not have the option of a safety ground, just plain don't...then what do you do? The simple answer would be to only use a 2-prong outlet, so you aren't giving the image of having a safety ground. I fully understand the reasoning behind not using a 3-prong outlet and tieing the ground pin and neutral pins together...however, it's hard to say which is a better plan. If you run only a 2-wire setup, and tie the new outlets/conduit (inner room, squarish stuff) to nothing, then a loose hot wire in a box anywhere would energize the conduit and since the conduit isn't tied to anything it would be dangerous...However, 2nd scenerio is you tie the conduit to the neutral wire, hot wire comes loose in box, it shorts out and trips breaker just like it should...no problem at all...But, 3rd scenerio, neutral wire comes loose and a device is plugged in and now conduit is at line voltage...

Ignoring what the NEC says basically it's about what wire is more likely to have a break in it...if the hot wire is, then tieing any conduit to a neutral is safer, in my opinion because you are giving any wire loose in any conduit a path to ground, it obviously should have it's own special-purpose path, but it wouldn't, but any path should/would work.

If the neutral wire is the one you think is more likely to come loose, be cut, etc...then you would obviously not want to hook any conduit to that, which I would guess means the conduit would not be hooked to anything, I have trouble seeing that as the 'better' solution, since it doesn't seem better...it would seem having the conduit tied to the neutral would be better than having it not tied to anything...

Any thoughts? (ha..I know there are thoughts...) :)

The first paragraph describes knob and tube wiring, down to the soldered connections, etc... Old and obsolete, but still legal and if in good condition, reasonably safe (absent the grounding).

Your options to put three prong receptacles in are to:

1. Run a ground wire from these receptacles back to the main panel ground or the grounding electrode system (that is the house's ground rod or the water pipe close to where it comes in to the house NOT any old water pipe in the house).
This will give you a real equipment ground.

or

2. Protect the receptacles with a GFCI and mark them "NO EQUIPMENT GROUND."

As for tying conduit and other exposed metal to neutral, you are in fact WRONG and in violation of the code. It would be better to have it float than be connected to a current carrying conductor intentionally.

Ok..thanks for the clarification.

Now, wouldn't a 2-prong outlet technically be 'ok' because you are not handing out a invalid image of something being grounded...obviously the labeled GFCI would be better, from a user-perspective, even though it wouldn't help safetey-wise on the wires getting to the GFCI outlet, but everything after would be more safe.

Think we will do the GFCI route...thanks for the knowledge..

I h8 old wiring... :)

Yes...you can leave the two prong receptacle. I thought your intent was to do otherwise.

How about this one:

My friend bought a condo, it has it's own sub panel inside of it, his meter is in the basement somewhere. After opening his panel he sees that all the grounds and neutrals go to the same bar, most are even under the same screw.

This is an old building and old panel, what was done is probably grandfathered in since no other electrical work has been done, right?

Is this a big risk to him? Should he pay to have it changed out?
He doesn't want to since all the wiring is 3-wire and all the receptacles are 3 prong so everything works fine for him. But I am definitely interested.

fotostat, neither you nor I have enough information at this moment to know if the installation is proper. Nothing in your post gives an indication that you are an electrician. Hire an electrician.

fotostat; why do you think it is a sub-panel and not the main panel?

If it is coming right from the meter it is probably the main panel and all neutrals and grounds are supposed to be tied together.

Go back up a few posts to blackadder's, a great explanation.

bus_driver, you avoided the question completely. My profession has absolutely nothing to do with the question I asked. If you would not like to help me learn, you need not post about it.

hendricus, the panel is in his unit, the meter is hidden at least 150' away in the basement behind closed doors with all the other meters for the other condo units. Would it be possible for neutral to be bonded to ground properly all the way up in his condo unit?

Sure, why not. The meter is placed for the POCO's benefit.

"Sure, why not. The meter is placed for the POCO's benefit."

I was under the impression that there had to be a main disconnect somewhere near the serivce entrance as well as the bonding of the neutral and ground.

The rules requiring customer-controlled disconnects near the meter are relatively recent. And many of them are unwritten, but successfully enforced. In the late 1960's, we did lots of jobs where the meter was on one end of the house and the panel (first disconnect) was near the center of the house. Standard practice at the time. Until the first protected disconnect, the service cable has only the POCO overload device at the transformer- and that is many times the amperage rating of the cable. There were cases where a duplex might have the meters side-by-side on one end of the building and the cable would run through the walls of one unit to the first panel in the second unit. It is illegal for fotostat to do any electrical work on the premises described.

Re the 2-pin vs 3-pin issue : if you're concerned about the presence of the grounding jack on a GFI, I believe it's acceptable to fill it with some kind of electrically inert material. Silicone might be all right. Someone please correct me if I'm in error on that.

An unconnected ground in a GFCI circuit makes no real difference.
The GFCI does NOT need the ground to function, and still provides protection.
The only thing it does not protect against is putting yourself between the hot and neutral with NO other current path.
If 0.005 A takes another path, the GFCI trips on the hot neutral imbalance.
GFCIs provide a protection that is actually better than a ground.
A ground is designed to carry the fault current and trip the circuit protection. You could be dead long before required current for a trip occurs.
GFCI devices are for personnel protection.