Can improper wiring actually cause a fire?

[R. Pierce Butler]

[e-mail] (Doug Miller) wrote in news:MEBfh.11287$ [e-mail]:

exactly zero

[Phisherman]

You betcha. I encourage you to ask your local firemen. They will be happy to tell you some stories.

[Doug Miller]

Unfortunately, what you said is *also* absolutely 100% wrong. The neutral in a pure 240V circuit does nothing. Period. It serves no purpose. There is nothing to connect it to, and in fact in most cases it is omitted. The safety ground is the equipment ground, the bare wire.

[Tim Douglass]

Yes.

See here for one example:

"We need to make a sacrifice to the gods, find me a young virgin... oh, and bring something to kill"

Tim Douglass

[R. Pierce Butler]

[e-mail] (Doug Miller) wrote in news:BsJfh.8244$ [e-mail]:

But there was no mention of a ground wire. ALl that was mentioned was the two wires to supply the 220vac and the neutral which, in this case, is the ground.

[LRod]

One of the things you must keep in mind is what code is today vs what code was yesterday, and even what it was the day before.

Your four wire 240V circuit to the stove is what is currently required by the NEC. It's also required to a clothes dryer. But it wasn't so long ago--perhaps within the last five years, certainly within the last ten--that there was a code exception that permitted using the bare ground as a neutral. In other words, using three wires as a feed. In fact, when I remodeled the kitchen in my 30 year old house, I pulled out the three wire range cord (which was permitted in 1973) and pulled in a four wire for the new range.

In my laundry room, the water heater was fed with 10/2 (no ground--also permitted in '73) and the dryer was fed with 10/2 (w/ground--again, okay in '73). I pulled the heater wire out entirely and moved the 10/2 wg from the dryer over to the heater, then pulled a brand new 10/3 for the dryer.

There are a couple of issues that seem to crop up regularly in these electrical threads that seem to confuse a lot of people. One is that folks as old as I am, especially if they worked in a hardware store (as did I), don't automatically assume a ground wire when talking about 10/2 or 12/3, even though that's the only way it's sold now.

Back in the day, if you wanted a ground wire with your two wire non-metallic, you better have said, "with ground," because if you didn't, you were SOL when you got home if you needed a ground wire. Yes, it was sold both ways.

The other issue that confuses is what's needed electrically and what's needed by code. 240V devices only "need" two wires to run. Period. They are both hot--there's no such thing as a "neutral" when you're talking about 240V. Now, the code requires (in most cases) a ground, so practically speaking, the 240V device "needs" a three wire circuit--not to run, but to meet code.

When it comes to devices like dryers and stoves, it's a similar story. The old code (up to 97?) permitted a three wire circuit (6/2 wg typically, for a stove; 10/2 wg typically, for a dryer). That was, as Doug says, to permit 120V clocks, microprocessors, etc. to function.

The current code requires four wires to eliminate the congruence of the grounded and grounding functions in one wire, which is not a good idea.

Frankly, if people would start thinking of a neutral more as a return path than as the same thing as a ground (which it is at the main load center, and only at the main load center) we would be a lot better off. A neutral carries current, a ground in a properly functioning circuit does not.

That's why there's no "neutral" in a pure 240V device (like a motor). both legs carry current. Just like in a 120V device, where both legs carry current. It's just that in a 120V device, the one current carrying leg is at the same potential as the ground. At 240V, they're both above ground. A lot of people are confused by that.

Someone mentioned a heater needing a four wire circuit, but I think that is inaccurate. There shouldn't be anything about a water heater that needs a neutral connection. However, I don't have an NEC book at hand to confirm that. You have to remember that not all 240V circuits have the same purpose. As has been mentioned, a 240V motor circuit doesn't need a neutral.

By the way, a water heater, of all things, would be the best device to cite that doesn't need a ground. In most cases it's in the very path of what the electrical service is bonded to in the first place. That's why the two wire feed was not only sufficient but safe enough to pass muster for many years. Probably the advent of CPVC plumbing brought about the necessity of a separate ground.

Alright, I've said that enough different ways for everyone to have a shot at grasping it. I hope it helps.

[Doug Miller]

Still 100% incorrect, in at least two respects.

First, the original post proposed using 10/2 romex cable, which consists of a black, a white, and a bare wire -- which are two hots and a ground. The 'troll' to which Toller refers insisted, incorrectly, that the circuit also needed a neutral in order to comply with Code; this is false.

Second, a 240V supply consists of two hots and a *ground*. Not a "neutral which ... is the ground." Neutral is not ground. They are not the same. And there is no neutral in a [North American] 240V circuit. Period.

[Pop`]

interesting or that I hadn't come across, and indeed, it did. The amount of misinformation there is large, especially with the assumed theories that were stated. I don't doubt your initial experience as I've seen it myself, but ... I think you exaggerated greatly and unfortunately made a lot of wrong guesses about what what and why. If you'd like some assistance in updating that page so it's accurate and usable as an FYI, I'm sure there are people here who would assist you in that endeavor, myself included. As it stands, it's a badly expressed example of a bad situation but your understanding of electricity is obviously lacking and in need of improvement.

Reagrds,

Pop`

[resrfglc]

Now, that's a response worthy of such a list. And he didn't take a shot at anyone in the process.

Just to clarify, my original intent (poorly done though it might have been) was to refer to installing a 240VAC run to a shop. While the OP indicated it was for a motor, my advice was to run a generic 240VAC run (thinking "down the line" as it were) that would serve the intended initial purpose and prove adaptable to others (run a 110VAC branch off, for instance) should the need arise - saving a re-wiring (not always a "pull" as most folks (and the OP indicated) use romex rather than individual conductors pulled through EMT (or equivalent).

I maintain that the advice/suggestion to use 10/3 (three conductors and equipment ground) over the alternative 10/2 (two conductors and equipment ground) would better serve the OP and most all of us save those who never err nor fail to plan perfectly for the future.

Or, for that matter, get confused by return path, ground, equipment grounds, neutral vs. ground, grounding buss bars and so on and so forth. (my category)

[Doug Miller]

Nobody *ever* criticized anyone for suggesting that 10/3 might be a better choice.

You still don't seem to have figured out that you were catching heat for your insistence that 10/3 was required by Code for a pure 240V circuit -- and, by the way, it's not "taking shots at" you to point out that a false statement you made is in fact false.

[resrfglc]

"10/3 was required by Code for a pure 240V circuit "

OK, let's get off this "You're Right, He's Wrong" track for a moment.

Let's say you call your County Electrical Code Inspector and tell him you want to run a 240VAC Circuit from your Main Breaker Box (say sixty-feet?) out to your Garage/Shop. what size conductors you should pull for a (40AMP?) load and see what he recommends.

My point being that, given that information, e.g. MAX 40AMP load @ 220VAC he's likely to suggest you pull the three conductors and the mechanical ground.

I agree he will, if pressed, allow that - if the circuit is dedicated to a water heater, for instance, that you only need pull the two conductors and the mechanical ground.

And, of course, the same would apply were you to specify the circuit would be dedicated to a specific electrical motor.

[LRod]

But that isn't enough information to give a definitive answer. As Marisa Tomei said in "My Cousin Vinnie", "it's a bogus question."

I don't agree. Based on my foregoing, I believe your imaginary inspector is going to ask the question you hint at below in order to find which of two or possibly three correct answers he should give you.

The only pressing in the conversation will be him pressing you for more information before he gives an answer, namely, what are you going to run on the circuit?

Which is exactly the kind of information he needs before he will ever give you a definitive answer, because there isn't a definitive answer without those parameters. That's what makes it a bogus question.

And, by the way, if it's a county inspector, he's far more likely to not really have that much interest, as opposed to a village, or worse, city inspector.

Finally, in addition to the fact that this is usenet and all answers are suspect by definition, whatever anyone says here, even if it's solid gold in the jurisdiction in which they live, there are places that not only have more stringent requirements than those in the NEC, but may not even base their own standards on it (Chicago is the largest notable example of the latter, I'm told).

[Joe Bemier]

Maybe this will help.....

[Doug Miller]

And what does that have to do with whether Code requires a neutral or not?

He's more likely to first ask what kind of load it's serving. And when he hears that it's a 240V motor, with no 120V loads, he's likely to suggest two conductors plus equipment ground.

If the circuit is serving 240V receptacles with no 120V loads, you only need to pull two conductors and equipment ground.

It doesn't have to be dedicated to *anything*. It can supply a 240V receptacle, or several 240V receptacles, and as long as there is no 120V load anywhere on the circuit, two conductors plus ground will be sufficient.

[J. Clarke]

[resrfglc]

"The standard U.S. household wiring design has two 120 volt "hot" wires and a neutral which is at ground potential. The two 120 volt wires are obtained by grounding the centertap of the transformer supplying the house so that when one hot wire is swinging positive with respect to ground, the other is swinging negative. This versatile design allows the use of either hot wire to supply the standard 120 volt household circuits. For higher power applications like clothes dryers, electric ranges, air conditioners, etc. , both hot wires can be used to produce a 240 volt circuit."

[resrfglc]

"as long as there is no 120V load "

My point, exactly.

The run, w/o he neutral, would be "dedicate" to 240VAC by your approach while mine affords he flexibility to employ the run otherwise without re-wiring from the MAIN.

"Is the ground wire necessary? The appliance will operate normally without the ground wire because it is not a part of the conducting path which supplies electricity to the appliance. In fact, if the ground wire is broken or removed, you will normally not be able to tell the difference. But if high voltage has gotten in contact with the case, there may be a shock hazard. In the absence of the ground wire, shock hazard conditions will often not cause the breaker to trip unless the circuit has a ground fault interrupter in it. Part of the role of the ground wire is to force the breaker to trip by supplying a path to ground if a "hot" wire comes in contact with the metal case of the appliance."

[bf]

I don't know if it could cause a fire, but if you use a wire guage that is too small, the wire will definitely get very hot. Obviously, if not wired correctly, there's a possibility that the electricity can arc, causing sparks which could ignite something.

But you're right, if done with care and common sense, wiring really isn't dangerous.

[Doug Miller]

Your "point" originally was that _even_in_the_absence_ of 120V loads, the neutral wire was supposedly "required by code". It's not.

Which was what the OP was describing -- and you told him he needed a neutral too. He doesn't.

While true, that's a separate issue from whether he needs a neutral when he does *not* have a 120V load.

[further red herring re: ground wire removed]

[Doug Miller]

What do you mean, "Hah!" ??

Nobody has disputed what you quoted above. The *entire* dispute in this thread has been over your uninformed, misinformed, erroneous insistence that the neutral wire was required for a 240V circuit that had _no_ 120V loads.