Can improper wiring actually cause a fire?

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"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.
conductors
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wrote:

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).
--
LRod

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wrote:

Maybe this will help.....
http://hyperphysics.phy-astr.gsu.edu/hbase/electric/hsehld.html
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On Thu, 14 Dec 2006 06:21:14 -0500, Joe Bemier wrote:

The trouble is that the Code is law and regulation, not physics.
--
--John
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"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."
http://hyperphysics.phy-astr.gsu.edu/hbase/electric/hsehld.html
Hah!

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wrote:

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.
--
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Doug Miller (alphageek at milmac dot com)
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Hah?????
--

-Mike-
snipped-for-privacy@alltel.net
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wrote:

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.
--
Regards,
Doug Miller (alphageek at milmac dot com)
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"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."
http://hyperphysics.phy-astr.gsu.edu/hbase/electric/bregnd.html#c3
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wrote:

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]
--
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Doug Miller (alphageek at milmac dot com)
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That's ok, but only up to the point where mis-information is being given.

Your point is incorrect. You might want to try exactly what you propose and see what your county inspector suggests.

I think you are assuming too much with this position.

Ok, so now we are back to the beginning of this thread. It seems you have arrived at the same conclusion that your adversaries were at when this started.
--

-Mike-
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Annually, over 40,000 fires are attributed to home electrical distribution systems.
These fires result in more than 300 deaths and over 1,400 injuries each year. Statistics
from 1992-1996 show level trends in each of these estimates with no indications of
decline. In 1996, $680 million in property loss was attributed to home electrical
distribution fires.1
Arcing faults are one of the major causes of electrical wiring fires.2 A 1994
insurance company survey of 660 electrical fires indicated that over 33% of these fires
were from arcing conditions.3 This data is further supported in a report by Smith and
McCoskrie4 that summarized the characteristics of 149 investigated residential fires.
http://www.cpsc.gov/volstd/afci/AFCIFireTechnology.pdf

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wrote:

How many of those 40,000 fires are due to having omitted neutrals from 240V circuits that don't need them in the first place?
--
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Doug Miller (alphageek at milmac dot com)
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snipped-for-privacy@milmac.com (Doug Miller) wrote in wrote:

exactly zero
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What he said was absolutely 100% wrong. The neutral in a pure 220vac does nothing but serve as a safety ground in the rare event that something were to go wrong and will help keep one from being shocked.

Sure.....anything can happen even in properly wired situations.

Fires that started from electricty are generally due to a few factors. A poorly made connection will causes things to heat up and get hot and could eventually cause a fire. An piece of wire carrying too much current will do the same thing.

That situation is one that could happen at any time. Romex is common in walls, ceilings and attics...eveywhere a mouse is likely to be found.
There are no 100% safe electric wiring, devices, etc. There are circumstances that can arise that will cause fire, death, injury, etc.
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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.
--
Regards,
Doug Miller (alphageek at milmac dot com)
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snipped-for-privacy@milmac.com (Doug Miller) wrote in

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.
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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.
--
Regards,
Doug Miller (alphageek at milmac dot com)
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snipped-for-privacy@milmac.com (Doug Miller) wrote in

Then why is neutral abnd ground in the CB box the same thing electrically? Both are uninsulated blocks bolted to the case of the CB box?
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On Sat, 23 Dec 2006 05:33:45 GMT, "R. Pierce Butler"

Because they do share a common point electrically--namely at the bonded junction in the main load center (and nowhere else). There, however, the similarity ends. The neutral is a current carrying leg of the circuit. It is a fundamental electrical requirement of the circuit. Without it the circuit will not work (120V circuit--there is no neutral on a 240V circuit). The neutral has to be the same size conductor as the hot, because it is the return path of the circuit and carries current.
The ground, on the other hand is not designed to carry current in normal use. It is a safety wire (so to speak) that is designed to bring the equipment to earth potential in the event of a failure of some sort which would cause equipment cases or chassis to become energized with line voltage. The next step in the process should be the tripping of the breaker, and in a GFCI circuit almost assuredly will be, but the ground's primary function is to bring the case or chassis to earth potential to mitigate shock hazard.
You would be so much better off thinking of a neutral as a return path (very analogous to the other hot in a 240V circuit). It's able to reside in the load center at the same potential as the safety ground solely because of the design of the Edison circuit (center tapped transformer at the pole).
--
LRod

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