Is It Safe to Use Neutral as Ground for 240V Infrared Rework Station in USA?

Hi,

I'm in US and I have a quick question.. I'm building a very simple infrared radiator rework station. I've used a couple from different companies that we're actually made for use overseas. I've been using my dryer plug for these for the past 2 years which is only 3 prong so no ground. The prongs on the stock plug that came with them of course are L N G. I'm running each 120v line to Live and Neutral then 'my' neutral is going to ground on the machine(case). I have no way to install or have anyone install a 4 prong 240v outlet so this is what I'm working with.

I have a few questions actually. For my build I'd like to wire it up right. I'm not sure if using neutral is good enough for ground. I know its tied to ground in the panel but is that really still safe? I have been doing it like this for awhile but would like professional opinion.

The other thing is I have a 120v grounded outlet pretty close to where I'm working. Can I just run a wire from the grounded outlet to the case of the machine? Those are all tied together too right?

Last question is about what kind of power switch/breaker I can use on the machine. I know GFCI breaker would be good but I can't switch it out. I also can't find a good match for my specs as far as mini breaker/on off switch goes.

Machine will be pulling about 16.5 amps absolute max. Thanks in advance!

You really should hire a Licensed trained Electrician before you electrocute someone or burn the building down.

People should avoid giving advise that requires a trained licensed electrician to install.

Thanks for reply. Nothing is being installed or modified in the house. I already know how to 'make' it work, as I've been doing it for a couple years with machines from China. For my own I'd rather build it a little better. I tried talking to an electrician before when I was hooking up one of these machines for the first time. He told me the wiring wouldn't work with US 240v. What I mean is I need to talk to a 'good' electrician and I live in small area where they don't know all that much if you could believe that.

I'm going to try to find one local though. I thought that's who was on here?

Earl,
I recognise what drove you to comment as you have.
Solid & definitive safety warnings are always appropriate, & if you wish, you can (as you have here), avoid further comment.
There are however many engineers of various persuasions & other technicians who use this site to learn from the competent contributors who willingly often go the extra mile to offer advice.
There cannot be much more important issues than earth safety & I am offended at your apparent desire to influence others in how they may choose to respond to this question.
I am Australia based (three pins 240VAC), & frankly I don't get the "4 pin issue".
So I was looking forward to being enlightened.
Guess we all have different perspectives.

I regret that I have offended you or anyone in this discussion. It is never my intent to disregard other's point's of vie in favor of my thinking, that is counter to learning.

Factually it is a good thing that we understand to some extent what a licensed electrician would need to do in an installation to make sure it is safe and to code. I have looked through some of what they are required to know and understand here in the US (NEMA) and it is simply astonishing.

In one case where I worked my manager asked me to connect up an iso transformer and also a 3-phase AC to AC programable 3KVA source, and I refused, even though I could wire it up. They were just trying to save time & money and for what, simply to speed up a testing schedule by bypassing correct safety procedure.

I like people to consider safety 1st. Not wanting ti insult or convince others my way is the only way to think.

The neutral and ground are safety seen not the same and even the connection on a plug must not be mixed.

The neutral is a active return path for your Line/Phase or in case a non balanced 2 phase / 2 phase.
The ground is a safety path in case their is a insulation defect in the equipment that must trip your fuse/breaker.

Technical it works YES but SAFETY it is a NO.
It is a main reason for electrical fires and electrocution from people.

Special heathers are known to have after some time insulation problems.

Only a proper and installed following the local code power line and socket must be used.

p.s. keep in mind if after a fire they find bad installation your insurance is not valid and you can be taken to the court.

@justanoob. In the US the correct wiring is L1, L2, N, G. In many older homes you will find L1,L2,N with no ground especially on 240V equipment. If a ground was needed in many cases the copper plumbing provided a convenient earth that large appliances could be connected to but as I understand there was no code requirement to do so. If the appliance needs a L1, L2, N, G then you need to provide that connection, The best thing you could do is rewire the circuit with 4 conductor wire and install an a 4 prong plug. Do not do connect to earth as a substitute.This can cause a dangerous condition. Connecting to the earth bus in the panel is the correct way to wire it. In general there should only be 1 point of earth ground at between your meter and distribution panel. A separate earth ground has the potential to create a "ground loop" that power can use the earth as a conductor. The NEC requires that if you do any wiring changes you need to upgrade the wiring anyway, so best advice is bite the bullet and pay to rewire the outlet.

bq). The other thing is I have a 120v grounded outlet pretty close to where I’m working. Can I just run a wire from the grounded outlet to the case of the machine? Those are all tied together too right?bq).

DO NOT connect to the other outlet's ground it's wiring is smaller and could possibly get hot---Dangerous--.

The manufacturer will specify what size breaker and probably wire size the appliance is to be connected to. Use the manufacturer recommendations in all cases.

A gfci breaker is probably not required in this case

I hope you understand now why your question provoked such a response. What you are proposing could create a dangerous condition. There are a few house fires each winter that are directly traced to old wiring in homes, many have been worked on by homeowners doing things like this. Don't be one of them.

By the way, electrical resistance heaters like I believe you are connecting are an inefficient use of electricity. If you have another method of heating this space you may want to consider it.

Thank you to everyone for your replies. They are very much appreciated. I understand your answer Peter but I'd really like to actually understand rather than take it hehe.

From 'my' noob understanding US 220v doesn't 'need' neutral. Why then would they have one? Also, if you could please answer this as its very important.. Can you please tell me if its ok to use a ground from a different 120v outlet? I have no problem ditching the neutral for the 220v and using groun instead.

The whole reason behind using a different ground from different outlet is for the simple fact I can't modify the existing wiring in the house.

I also understand the safety thing believe me. I'll explain later maybe haha! never got shocked or anything.

Hi Chuck, thanks SO much for your response!!!! It really does make sense now and that's really why I was asking. I'm not a homeowner and that's actually the problem. If it was me I would upgrade the wiring to 4 wire outlet and use a gfi breaker in the box for that circuit.

If you have the time I would love to chat with you. If not, I understand.... You can reach me at norcalxbox360repair(_at_)gmail.com.

norcalxbox360repair at gmail dot com


This is not for heating my home. I'm building a machine to be used to rework motherboards. The current machine I'm using on my 3 prong outlet(been doing this for years) is the jovy re8500.

http://www.google.com/imgres?num=10&hl=en&saf...194&start=0&ndsp=35&ved=1t:429,r:17,s:0,i:143

I am really learning alot about all this and the help is greatly appreciated believe me. Thanks again!

First let me answer your second question.
No do not use the ground from a other plug you do not know the wire rating from that plug so do not mix. Or make redneck installations ( they do kill)

Then your first question yes technical if you need only 240 V you do not need the neutral.
but do not use the wire from neutral as ground. yes it works but it is not safe and by code.

The code is their not to make your life difficult but to safe your life and property.
My last project was a switch power supply that burnt out its surge protector by a client if the grounding was not by code it sure started a fire i was in front when it started and it sounded like arch welding inside, first the breaker tripped and then the smoke came.

because of safety i am still a live with ten fingers etc. . I am a commissioning engineer and have seen a lot of wrong situations or be asked to investigate after a accident.

@Peter__ I got your message in email but not showing up here. Thanks for reply. I have been running these machines for years like this with no thought of risk but starting to worry me just a little bit now......

I wouldn't contest what you say at all. I think I'll just talk to landlord and pay to have licensed guy install 4 prong outlet which would make my problem disappear.

My question really is 'why' is it bad to use neutral as ground in 240v US 3 prong outlet? Would it not make the breaker trip? Since they are connected to ground in panel?

Please believe me when I say I will be as safe as possible. I'm just trying to understand. I'm not willing to risk my life or my families for this DIY project.

THANKS!

I know this sounds daft but ive had similar experiances in the UK so have many engineers here in the uk

Tohe favourite trick is ask someone to take on a job They do the job then what they do is set you up

Make a compliant to trading standards and finally procceed with reporters and possibly sue you as well

Ive had many experiances with customers where we know full well that the job has been done properly and safley and where customer,consumer then calls in second person and even third person and then pulls the same trick and guess what happens

They then point finger at first person

In fact this is what we call pass the buck story

Ive got a classic case Im having to attempt to sort now where the director has purchased an entire company and what they have done is dumped a load of trash on him simply becuase they have taken advantage of the fact that hes not technically minded

He obviously hasent seen changes comming

The previous owners have sold off as quickly as they could Guess whos stuck with the problems

The new owner, The dealers, the customers, shops, The enginners who have to sort the problems out and who else

Correct the next set of events that occurr are namley the poor blastered factory based abroad then gets the blame as well

All because one previous owner thought hed take the piff Thats about as polite as I can term this

Hence Earl is correct regards this as if anything should go wrong

Someone will point fingers and try for a claim and say "Aaah but ive got a copy of this site that said it was a ok to do this and it was their advice blah blah blah " ,before you know it the so called questionare then attempts to sue the site and its members for damages etc etc

Trouble is like Earl I know only to well how these sons of guns work and exactley how far they will go just to try and make a fool out of someone

In fact they do this and make a living just doing this all day long and whats more they get a kick out of this as well

Nevermind all the other trouble they cause or just how much damage they can do to you which in one example that I know of just for simply doing one of them a favour resulted in a two year prison sentance where some clever so and so decided to set them up

Not funny when you are running a business or are self employed

Thats without manufacturers and the trouble the importers cause becuase current government doesent insist on trade testing and safety checks

I wont even go into staffing problems or the trouble they can cause as well thats without the fanatical health saftey so called have a go specialist many of whom you will undoubtably come across in the Uk as well, very clever so called experts at thier job but dont know anything at all


So I cant blame Earl at all for this because very simply put there is always one person that will definately do just this and they thrive on this as well

With all due respect I do understand your request equally you may not be a trouble maker but someone else reading content on this site will be and thats 3/4 of the problems in the uk as well now

As usual they have to mess it up for everyone Typical this

One of the most important reasons is that neutral is not true earth

In fact you can electrocute yourself btw neutral and earth

The other reason is that plumbing, taps etc are all tied to earth They have to be by law inclusive gas piping

Bearing this in mind what happens when some one is in the shower, bath tub or wasing thier hands and your appliamce decides to arc to earth
Yes bang, wallop, smash, one massive heart attack and they are possibly cases for the funeral directors or possibly left parralized for the rest of thier lives

The other reason is that earth leakage works on the potential difference btw neutral and earth

The easiest way to physically test this is simply touch earth and neutral together momentarily and the rcd should trip

Finally In the USA you have massive lighting strikes

Well you wont be looking to clever if you are operating your apparatus whiLst god hurls his famous ligthing bolt at your satelight dish Tv antenna or chimney stack will you


In fact electrical standards are so bad in the UK that they are having to rewire all shops, all private rented accomodation, factories you name it and you want to see some of this fantastic workmanship as well inclusive light fittings in the bathrooms switch bourds nevermind how they have the run the gas pipes or wimpey homes where they havent even bothered to run a bloody earth

Not to mention signed saftey checks which have been signed off without the gas pipes being earthed correctly by so called certified inspectors Eg Infinity housing never mind this little abode here either This you have got to see Its an electricians nightmare

Yes I have this so called documentation etc as well as photos

Then finally we get to arials and satelight dishes With no lightening arrestors Not looking very clever now are they In fact to compound matters according to the uk super duper sales persons We dont need engineers any more

Im so pleased to hear this because at this rate they wont have any that will work for them iether or have any trained Ever so pleased am I that they are this confident especially in wake of the EU fines on the way

Only I wont be around to participate in tjis fiasco they can get on with it on thier own seeing as they are such experts

Merry Christmas with cherries on top

And that is why

It is not an unsafe condition to make a 240 volt supply to your equipment. The reason for the no ground on the 240 volt drier circuit is simple, nothing used to utilize an equipment grounding conductor and equipment such as washers and driers all came equipped with a little extra green wire originating on the frame of the appliance with instructions to attach it to a water pipe at the appliance for safety grounding assurance. That is because the neutral on a clothes drier(Break)
Sidebar: USA lower 48 supplies residential dwellings with a 3 wire service drop to the point of attacthment consisting of 2 each insulated lines of a different phase and 1 each bare conductor which is technically called the grounded conductor. Either of the ungrounded conductors combined with the grounded conductor will reult in a potential of 120V nominal.
Use of the 2 ungrounded conductors without a grounded conductor connection will result in a 240v nominal potential.
Use of the 2 ungrounded as well as the grounded conductor will result in a supply called 120/240 so small things like timer motors etc. may be run from the lower voltage.
Now if you look at your overhead drop, you only see 2 conductors but upon closer inspection at your point of attachment at your riser you will see that the bare support(MESSENGER) wire has an electrical connection to an insulated conductor emerging from the weatherhead that is either white in color or physically modified either with tape, paint or other means to signify that that is the grounded service conductor for this installation. If you followed that wire to the pole, and have access to the line of poles, you will see that every couple or few poles there is a utility half round conduit running the length of the pole that carries a conductor from the grounded supply conductor up top to the earth into the hole with the pole. This creates the grounded reference for the system which transformers usually connect to at some point and without which the secondary voltages will do some pretty interesting acrobatics floating all over the place.
Do not confuse the equipment grounding conductor with the grounded conductor. They connect at only one place and that is at your service entrance to your house. The service entrance is where your meter receives its' feed fromk the service drop to your property, changing ownership at the service point(weatherhead splices). Coming in you have insul insul non insul(from them) and switches to 3 insulated on your equipment consisting of 2 ungrounded and one grounded conductor>AT THE SERVICE AND ONLY AT THE SERVICE AND NO WHERE ELSE IN ANY PANELS OR BOXES OR CONDUIT FITTINGS THE grounded conductor AND THE grounding electrode conductor AND THE equipment grounding conductors WILL BE BONDED TOGETHER BY MECHANICAL MEANS AND ALSO BONDED TO ALL METAL PARTS OF SAID EQUIPMENT.
The grounding electrode conductor runs from the service to a pair of grounding electrodes(In Calif it is the water pipe if metal within 5 feet of entry to the structure and considered your primary electrode. Here we also use a supplementry electrode most often in the form of a steel core copper clad rod of a minimum 1/2 diameter and 8 feet in contact with the earth.)
UNBREAK>>>
The Neutral as has become the slang, because it is anything but 1/2 of the time, the grounded conductor only bonds with the equipment grounding conductor at the service to keep the potential throughout the home distribution wiring to the point of use at a (0) ZERO potential so that if there is a an equipment failure of some sort where the body or case becomes energized there will be available a carpool lane so to speak with no cars in it at all unless it is an emergency and that emergency is there to be sacrafised so that you do not become the equipment grounded conductor or the return wire to earth.
Remember this is ac power, therefore inside a circuit 60 times a second for our grid that wire is of a different and opposite polarity. It is just following the magnetic rotation of the generator which is turning at some multiple of 60. That is the only generation frequency that I have experienced on land in the USA including Hawaii.
So a long story short, the dryer uses a 110volt motor and timer, and the heating element is 240 volt which is why the neutral is sometimes referred to as ground. And that works with the extra little green wire attacted to the water pipe. AND only if the feed for the dryer comes from the service entrance and NOT FROM A SUB PANEL. If it came from a sub panel (WHICH HAS A 4 WIRE FEEDER CONSISTING OF 2 UNGROUNDED CONDUCTORS AND A GROUNDED CONDUCTOR AND AN EQUIPMENT GROUNDING CONDUCTOR) and is hooked up with the neutral as ground also you have just crippled your safety ground in your sub panel by bypassing the dedicated emergency lane back to the service.
Realize, every time you utilize powel from an outlet, be it a light , appliance, plug, etc, anytime, as soon as you connect and energize equipment utilizing 120v that not so neutral conductor now has a 120 volts of potential on it. Don't believe me, want proof, don't recommend but pull the branch neutral for the circuit in question, whatever is energized will denergize and put your meter between that NOT SO NEUTRAL grounded condctor AND THE NEUTRAL BAR YOU JUST DISCONNECTED IT FROM. Be careful as that is a full 120 volts of flesh burning heart bursting potential. Touch it to ground accidentally and you will see that you also have an arc welder capable of instantaneous blinding metal melting if you are lucky light. Worse case is an ARC FLASH which is and arc welder melted metal propelled by a hand grenade and it will destroy most anything in its' path without the proper precautionary,protective, and safety equipment. And if too massive a destructive fault occurs, no amount of equipment will save you as it is akin to being at ground zero of a bomb exploding for a fraction of a second. Residential breakers are for the most part limited to 10,000 amps interupt ratingsd meaning the will break below that theoretically hopefully in less than, way less that one cycle,, or 1/60th of a second. The available fault current interrupt ratings on anyhthing seen for a home is usually 10,000 for the generic with 22,000 and 65,000 for some of the better poduct lines bordering on industrial such as the QO line. Other vendors have their equals.
THE BOTTOM LINE IS THIS, (proceed at you own risk and liability as we are not recomending you do this as I have no knowledge of your background, training, skills, or qualifications) If you want to safely use your dryer outlet to power your rework device, and it needs srtrictly a 240 volt supply the runs in to a transformer for the various required voltages demanded by the equipment. And there are only 3 conductors in the attachment cord to the unit. IE 2 blacks and a green, or black red and green, with no white or grounded conductor, and you do not need the outlet for an electric drier(ie you either do not have one or use a gas 120 volt model)BUT BY NO MEANS WILL USE AN ELECTRIC 240 DRIER UNTIL CIRCUIT IS RETURNED TO AS INSTALLED CAN IN THIS ORDER.
1) SHUT OFF 240 VOLT 30 AMP BREAKER AND DISCONNECT WIRES
2)TRACE RED AND BLACK WIRE BACK TO WHERE THEY EMERGE FROM CABLE
3)TAPE THE WHITE WIRE WITH GREEN TAPE AND MOVE TO THE EQUIPMENT
GROUNDING CONNECTION WITH THE OTHER BARE AND OR GREEN WIRES
4)GO TO THE RECEPTACLE, PULL THE COVER AND REMOVE THE ENTIRE
RECEPTACLE COMPLETELY
5)TAPE THE WHITE WIRE ALSO GREEN AT THIS END SO YOU NOW HAVE A
PAIR OF UNGROUNDED CONDUCTORS FOR 240 VOLTS AND A SAFETY VIA
A DEDICATED EQUIPMENT GROUNDING CONDUCTOR WHICH WILL GROUND
THE CASE OR CHASSIS DIRECTLY TO YOUR GROUNDING ELECTRODE DOWN
OUR CARPOOL LANE.
6) how safe do you want to be????????
The above will work and be safe only if your power connection remains capable of the carrying the available 30 amp current the breaker for your dryer was rated at. and do this up into your device to a pair of fuses to limit the current to an amount the device wiring and circuitry are constructed to withstand.
By utilizing several sections of the NEC you can arrive at the industry standard of any single utilization equipment load a circuit to a maximum of 80%. Your 16.5 amp device would therefore exceed this demand requiring a 25 amp breaker minimum. If it was 16 amps, use a 20 amp 2 pole (COMMON TRIP)240 VOLT BREAKER. {common TRIP}[CoMmOn tRiP] common trip common trip ...............
In te event of a fault it opens both legs simultaneously. I would recomment you install a different receptacle that did not include the 120/240 rating and was a 250 volt single phase 3 wire device so as to not inadvetently plug some other appliance in by accident.
Your number 10 wiring is adequate, and a 30 ampp breaker will work for the unit but unless there is a veryt high start up or surge current the overcurrent value is a bit high. BUT AS I STATED, IF YOU USE A 30 AMP CONNECTION ALL THE WAY TO THE DEVICE OVERCURRENT PROTECTION, IE FUSES THE FIRST CONNECTION OF THE INCOMING NUMBER 10-3 SO OR SOW CABLE, I WOULD RECDOMMEND A LOWER OVERCURRENT DEVICE.
tHE DRYER CONNECTIONS WERE A 10-30P AND A 10-30R WHICH WAS 125/250v 3pole 3wire connecting device.
You need to go to a straight 250 volt device as you no longer have the "neutral' only line times 2 and ground.
New non locking would require a 6-30P and a 6-30R or locking an L6-30P and L6-30R if you leave it at 30 amp breaker. If you change to 20 change the 30's to 20's ion the connector model numbers. Every voltage,# of poles,#of phases is different in the connectors as a safety standpoint protecting both the equipmnet, the premises, and oh yeah the most important one of all, The unskilled, and in some cases blatantly flirting with their life in this day of the dumbing down of America so everyone can feel good about themselves for being lazy leaches on society expecting a reward for nonperformance or personal effort.,,,,,, oops, sorry about that folks, just please
BE DAMNED CAREFUL BECAUSE ELECTRICITY IS LIKE A BOULDER BALANCED AT THE EDGE OF A CLIFF HELD IN PLACE BY A TOOTHPICK. NOT A NICE THICK REALLY GET IN THERE TOOTHPICK BUT ONE OF THE FLAT AT ONE END TO A POINT AT THE OTHER MADE FROM LEFT OVER SCRAPS AT THE PALLET FACTORY. IF YOUR NOT CAREFUL FASTER THAN YOU REALIZE OH SH.......YOU ARE DEAD.
If you can manage it, do it in the daylight at the panel with it deenergized, leave it disconnected until finished on the other end if you must turn power on for light, then go back and again deenergize the panel and reconnect and verify everything before buttoning things up.
Then test at the receptacle. You should get 120, 120, and 240 or something close when metering L1-G/L2-G/L1-L2 AND 0 G TO A WATER PIPE.
very last thing, Gas and water lines are usually bonded together most ofter at the water heater because the water line is your primary grounding electrode and it is a convenient place to jumper the 3 pipes and connect them with short wire(#6 bare solid copper, one piece) This is because of things like pumps, stoves, funaces etc that could energize those lines if there is a fault condition happening. Good luck and please please please exercise extreme caustion and as initially stated, kids, do not try this at home, it is a job for skilled professionals, and just because your card says engineer, that does maketh an electrician not. And all the book learning in the world will not save you if you touch the wrong piece of metal, even if you only touch it a little bit or for not very long. The NATIONAL FIRE PROTECTION ASSOCIATION issues an update to the NEC every three years for two reasons, to keep up with technology, and most importantly, becuase LIVES AND PROPERTY ARE STILL BEING DESTROYED BY THE MISUSE OR MISHANDLING OF ELECTRICITY IN THE FORM OF ELECTROCUTION AND FIRE.
I have witnessed dirt boiling, solid ground turn to boiling dirt from an electrical fault, high voltage shorts turn the atmosphere around you from orange to blue as air ionizes depending on the humidity and weather. AND IT WILL WILL WILL WILL TURN YOU INTO A BURNT INANIMATE OBJECT IF YOU GIVE IT EVEN ONE TEENY TINY MINISCULE CHANCE.
gloves, safety glasses, long sleeved heavy wool or flannel DRY shirt, jeans, (no officewear now fellas),and gals) rubber soled shoes,(hikers, athletic) and if it is wet out make a tent overhead and after it is up laydown plastic-wood-rubber mat in that order so that you may not advance to equipment grounding conductor today.

Patrick:

I see on you BIO that you are a member of the IBEW. Are you still practicing, of have you perhaps retired from the trade. Wondering in the sense of years in the trade.

Yeah what he said ^^^^^^^^^^^!

If you composed that all yourself I applaud you sir.

No really..... I agree with what I read above and I may have missed it above but I wanted to point out a specific hazard of ground loops.

A separate electrode not bonded to the building electrode system will cause havoc with the electronic equipment if there is any nearby lightning strike or if in a storm a surge is produced on the grounding network. Your isolated grounds may be at thousands of volts different from the building grounding point and everything in the building referenced to it. Fire is a real possibility. You can also expect small voltage potentials in normal usage, which will corrupt the ground reference the equipment may be relying on.

And if you like formula http://en.wikipedia.org/wiki/Ground_loop_(electricity)

Someone commented:

""A separate electrode not bonded to the building electrode," I know what an electrode is but this particular is extremely vague, what do you exactly mean, perhaps an example. When you state ground loop that sort of hints at what I believe you are trying to explain but aging I'm just guess when you use a term vaguely.

Wow Patrick thanks! I really learned alot from all you guys and I really appreciate you taking the time to respond.


I broke down and bought a step up transformer. The guy I bought my current machine from told me he ran it on a 20amp dedicated line and worked fine. I decided to go another route with the machine I'm building as well. At 100% max it'll only be maybe but running at 1500w. Even with transformer no probs there.

Thanks again guys and Patrick that was the most informative post I've ever read anywhere. Sweet dude.

Patrick,
Holy shit you made my head spin.
I could not grasp it all, mainly because you have "included everything" but apparently forgotten about layout & paragraph structure.
It seems from what is posted here that many domestic & small business electrical supply connections both in the UK & US are substandard in as much as an earth may or may not be routinely wired to each wall socket.
I can't grasp how this could be so maybe I have misread the essence of several posts.
Here in Australia all 240 VAC single phase mains wiring is supplied by 3 conductors(L, N, & E). An exception is allowed for ceiling mounted light fixture supply, which I can't really explain given the comments here about fire potential.
Anyone care to further enlighten?

I am sorry, I ass u n me'd that folks foreign to our system realized that here our basic line voltage is 120 volts and to get 240 fromn our configuration we use the 2 ungrounded (hot, line, overcurrent protected, has a breaker) condutors with the load inbetween them as opposed to an ungrounded conductor and a grounded conductor(LINE AND NEUTRAL). oUR SERVICE IS 120, AND 120 AND WE ONLY ARRIVE AT 240 BY COMBINING THE 2 OR USING A STEPUP TRANSFORMER ON A SINGLE LINE.
As far as my Inglase goes, it was my least enjoyable subject in college when Unca Sam was paying me to go and in return I was in the boat repair business for him. Problem was, every single boat but 3 or 4 that I worked on for them, well they just went and sank for some reason. Hope it wasn't something I did in the reactor. On another sad note I see an important piece of our history is being decommisioned soon and that is the CVN65 Enterprise. I did a lot of, well lets just say I got real familiar with her many reactors.
PS. all the boats that sank resurfaced at a later date. ;>)}
And as far as the infrastructure in our industrial and commercial there is a real national effort to moderniniize and go green so in the interest of the almighty dollar, the corporations will generally keep the electrical in good condition. It cost far more to pay survivors or medical treatment and rebuild from a fire or explosion or a short circuit on a main line that it does to stay ahead of the game. The country is full of abandoned buildings, but in these the electrical is not a problerm because the freaking junkie copper theives have stripped out alll the wiring. Tqargeet practice. Well I just finished my monostable controller circuit design, it's late, my marginal typing skills are fading fast, and time for a long winters nap. Oh, the 2 ungroounded conductors are on different phases. So yeah, we differ from both you folks on the southern island and across the pond in our 240 is our lesser used voltage in a residential and commercial instqqallation, with small appliances, computers, tv's stereos, handtools and just about most all but high demand items like electric dryers, electric watrer heaters, electric stoves, ac condensing units, and not much more in a house being the only 240 volt loads. yawn, night all.
Have a safe, healthy, prosperous 2013 for your and your families.
Oh, and I learned how to let the magic smoke out of electronic devices at a very young age when the batteries went dead. I just would grab some wire, chuck the batteries, and connect the things to the socket on the wall the lights plugged into. Watchout baby. By the time I was 12 and wanting my guitar to go electric, only way my dad would get me an amp was a little red combo that came in a box with a bag full of parts. Hence started a lifelong informal affair with the magic of analog sound and tube amps in particular from my guitar obsession. Still use tubes, slowly making the jump from analog multitrack recording rig to digital. But my studio I use an old 8086 without even a clock card because the damn thing still works and is as stable a machine there could ever be. I lock it to tape via sequencing software and SMPTE time code on an outside track. But I digress, this isn't about that. Goodnight BE SAFE.

Still in IBEW and still practicing, one of these days I will get it right. Actrually, My brothers and I are all required to be state certified and recertified every 3 years with a minimum of 32 hours of continuing educattion in the field thrown in. But what would I know, just another overpaid member of the middle class ruining the country.
Did you here the one about the fund raiser dinner, A union member, a politician, and a corperate ceo were sitting at a table, the ceo put all the cookies but one, which the union memeber fellt lucky to get, in his pocket and turned to the politician and said would you look at that, that union guy took all of the cookies.
I have to also ask that of all the millions of people there are in this country, and then observe the circus going on in congress right now, must say SERIOUSLY, IS THIS REALLY THE BEST WE COULD COME UP WITH OUT OF HOW MANY MILLION PEOPLE. If I don't do my job, well, I am sure it is the same for the majority of you.

I am confused by the use of the term building electrode. Are you refering to the practice of bomnding the structural metal of steel framed buildings to the grounding electrode system?
In a light commercial or residential installation, the two points considered the grounding electrodes are indeed bonded together with a minimum of number 8 solid copper. Also the code lists 7 possible grounding electrodes, and if any two are installed as part of a separate grounding electrode system, the may be no closer than 6 ft from each other. Two or more grounding electrodes that are effectively bonded together shall be considered a single grounding electrode system.
The metal underground water pipe,
2)metal frame of building or structure where effectively grounded
3)concrete encased electrode (rebar or 20 ft min #4 cu encased in 2 inches of concrete
located in and near the bottom of a foundation or footing in direct contact to earth.
4)Ground ring (#2 smallest not less than 20 ft long in direct contact with the earth at least
30 inches deep.
5)Rod and Pipe electrodes
6)plate electrodes
7)other local metal undergorund systems or structures
Not Permitted are metal underground gas piping systems or aluminum electrodes.
I have dealt with ground loops in installations used for audio recording when installing the audio interconnections and patch bay systems as not all manufacturers of audio processing devices adhere to the same grounding scheme for their products and on a balanced audio system their is a signal ground and a chassis ground. Different animals.
There was a study I recently read about on the NFPA site that addressed the variables in soil conditions and the resistaance change over time due to corrosion and soil moisture content and makeup and the resulting change to the code specified maximum resistance
allowed for grounding electrodes that was originally started by private parties and used 6 sites in and around Las Vegas with varying soil makeup, but was expanded to include sites in Boston, California, and a couple oother different geographic locations to examine the changes in the effective resistance to earth on 18 grounding electrode scenarios with a means to measure them equally as to take the measurement act itself out of the equation to aquire as accurate data as possible. Very interesting stuff. But to worry about multiple electrodes on the same system, aas long as they are bonded together physically, they are considered one grounding electrode system.
I must also correct myself as earlier I stated the purpose was to limit the faault current was backwards. The overcurrent device limits the current and the grounding electrode system up and including the grounded conductor limits the voltage in a fault condition.

Verbatim: Electrical equipment and wiring and other electrically conductive marterial likely to become energized shall be installed in a manner that creates a permanent, low- impedence circuit capable of safely carrying the maximum ground-fault current likely
to be imposed on it from any point on the wiring system where a ground fault may occur to
the electrical supply source. The earth shall not be used as the sole equipment grounding conductor or ground fault current path.

@ Earl, I'll give you my example where I got involved with likely ground loops, others may be referring to completely different set of circumstances especially the Aussie where I have been told they use a SWER system where earth and neutral are essentially the same thing.
On solar installations the DC solar modules are frame grounded, so the mounting structure must be grounded to an electrode at the array. Usually the DC negative is connected to the frame in each module, some are positive ground. The potential for a ground loop from the inverter through the home ground electrode is there whether the grid power is on or off. The potential for a ground loop from grid power is also there whether the inverter is on or off. The most common way for the inverter manufacturer to provide a safety in this event is to place a 1 amp fast blo fuse in the ground circuit, at the inverter. The real trick is not to just separate the grounds with the blown fuse but the inverter must also turn off in the event of a blown fuse. In any troubleshooting of this fuse being blown, the technician must be very aware that the condition may still exist. A unwary person could touch the modules frame and be shocked by a loop from the modules through the ground.
I know this is not the most common danger but we need to be aware of it and proceed with caution.

Technically the neutral and ground are one in the same. Technically, in many situations, a non-current carrying ground 120V AC system (Hot/ current carrying neutral/non-current carrying ground) is used. On 220V AC appliances like electric stoves and electric dryers, the neutral and ground have been one in the same for decades (Hot/Hot/neutral and ground tied together) using a 3 wire system. Newer wiring use a 4 wire system - Hot/Hot/Neutral/non-current carrying ground. If you are using 220V AC devices, the neutral/ground is not used for any 120V application, so the neutral/ground is being used specifically as a ground only. There would not be any conflict with current codes, and there will not be any compromise in safety. Technically you would only need a four wire system if there were any 120V devices, which you do not have, in addition to the 220 V devices.

A dryer plug and recepticale are rated at 30 Ampere. Code only allows 80% rating for continuous draw, so a 20 A breaker is marginal (16A for continuous draw and you have 16.5A), so I would suggest a 25A breaker or a 30 A breaker. Bolting the neutral/ground to the metal case is exactly what it is intended for - a safety for if a hot wire comes in contact with the metal cabinet to prevent elecrical shock.

I have been working with power distribution systems and motor control since 1973, and an electrical contractor for residential through industrial since 1978 with four employees. I see no conflicts or safety concerns. I have 3 years of specific electrical training and decades of installation and service. I am not a rookie and I am not guessing.

sorry to disagree with the safety part, and yes as already stated above technical it works but is not safe.
And if you re read your training books you will find that residential neutral and ground are only connected at one and one location bonded together. And that is inside a fuse board.

At industrial power distribution it is a other situation, there there are trained personnel working and preventive maintenance is scheduled. Also in industrial systems there are several neutrals and ground to keep separated digital, automation, instrumental, high voltage and low voltage lines.

Next to that the original question is asking if he can use the connections on a 3 prong plug with out ground and connected the ground to neutral. And as you are a where on a older installation where we can aspect no maintenance and not good balanced neutral can be floating. and that is a safety problem that can and our history has proven to given bad effects.

Well done! ! All qualified electricians who know anything about what they are doing will tell you exactly the same

You dont get a second chance with this that simple