Author Topic: If the electrical energy is outside the wires, how is insulation protecting us?  (Read 9580 times)

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Offline typoknigTopic starter

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This question stems from the Veritasium video (below) and Dave's analysis of that video (also below).  Both Derek (8:56 in his video) and Dave (5:17 in his video) say that the fields carry the energy.  I am not disputing this, but what I don't understand is why am I not getting shocked when I grab an insulated piece of Romex if all the energy is "outside" the wire?



« Last Edit: April 01, 2022, 03:15:58 am by typoknig »
 

Offline andy3055

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You get a shock if you conduct electricity through your body, so to speak. The energy referred to in this case is magnetic energy and that does not shock you. This is the simplest explanation.
 

Offline typoknigTopic starter

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You get a shock if you conduct electricity through your body, so to speak. The energy referred to in this case is magnetic energy and that does not shock you. This is the simplest explanation.

Are you saying that there is some "energy" other than the energy that Derek and Dave are referring to?  It seems to me that the videos are saying there is only one kind of "electrical energy", and that energy exists in the fields outside the wire, but your response makes it seem like that isn't true.  What is the other energy that is shocks us?  Does that energy "flow"?
 

Offline andy3055

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I do not comment on other people's videos. The magnetic energy is the result of the electrical energy.
A simple example would be touching a hot plate. Would you get shocked? You will get burnt, if it is hot enough. The heat is a result of the electrical energy.
 

Offline TimFox

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I agree with andy3055.  The electrical shock suffered by the victim is the result of electrical current flowing through the body.  A classic demonstration of electrostatics is to put an attractive female with long light-blonde hair on a carefully insulated platform and charge her with a Van de Graaff generator:  her hair will fly out from her head, but (unless something goes horribly wrong) she does not feel a shock.  (I saw this in high school almost 60 years ago, but it's probably not done in public schools anymore.)  There is a large body of safety literature about what affects this current for different conditions (e.g., skin moisture and electrical frequency).
 
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Offline IanB

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A classic demonstration of electrostatics is to put an attractive female with long light-blonde hair on a carefully insulated platform and charge her with a Van de Graaff generator:  her hair will fly out from her head, but (unless something goes horribly wrong) she does not feel a shock.

You mean like the picture on the left?  :)
 

Offline TimFox

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Exactly.  Although my blonde classmate was cuter, with finer hair.
 

Offline typoknigTopic starter

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I do not comment on other people's videos. The magnetic energy is the result of the electrical energy.
A simple example would be touching a hot plate. Would you get shocked? You will get burnt, if it is hot enough. The heat is a result of the electrical energy.

I don't think this is a good example.  A hot plate isn't a bare conductor.  The part exposed to us is an insulating metal oxide tube which is also grounded.  Touching it would be the equivalent of touching a really hot wire (assuming the wire's insulation wasn't at the point of melting off).  A toaster oven on the other hand has exposed heating elements.  If you touch them you will get electrocuted in addition to getting burnt.
 

Offline nigelwright7557

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You get a shock if you conduct electricity through your body, so to speak. The energy referred to in this case is magnetic energy and that does not shock you. This is the simplest explanation.

The energy is in the magnetic and electric fields which are at 90 degree's to each other.
Neither of which will shock you.
Shock is caused by electrons moving into your body.
 

Online Someone

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say that the fields carry the energy.  I am not disputing this, but what I don't understand is why am I not getting shocked when I grab an insulated piece of Romex if all the energy is "outside" the wire?
Dispute it! If there was a pile of energy outside the wire then it could be harvested:
https://hackaday.com/2017/04/10/wirelessly-charge-your-phone-from-high-voltage-power-lines/
Which works in a changing (alternating current) field. It would be possible to come up with some contrived examples where a conductor with insulation that would be safe to touch at DC, would give you a shock when carrying some high frequency RF energy.

The sleight of hand that the electrical riddle exposes, is the transition from steady state in open circuit to another steady state DC operation with the lamp on. Between these states there are changing fields and energy outside the wires, that is measurable and well accepted. But after some time (seconds for that exaggerated thought experiment) its back to DC and there is no energy outside the wire which you can interact with or get shocked by.
 
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Online SiliconWizard

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So then, what is energy? ;D
 

Offline aetherist

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This question stems from the Veritasium video (below) and Dave's analysis of that video (also below).  Both Derek (8:56 in his video) and Dave (5:17 in his video) say that the fields carry the energy.  I am not disputing this, but what I don't understand is why am I not getting shocked when I grab an insulated piece of Romex if all the energy is "outside" the wire?
The answer is that Derek & Dave & Nick & Mehdi & Brian & Bob & Co are all wrong. The energy is not (wholly) in the fields.
If u have to touch the wire (or nearly) then the energy is due to something in or on the wire.
Old (electron) electricity says that the energy (force) is carried & transmitted by slowly drifting electrons inside the wire.
My new (electon) electricity says that the energy is carried & transmitted at the speed of light via electons (photons hugging the wire) on the surface of the wire.
Both electricitys satisfy the fact that insulation prevents electrocution.
The problem in a way involves the terminology. The electric energy is produced somewhere somehow. It is located somewhere in someform. It is carried by something in someway. 
And all the time or sometime electric energy is also radiated as em radiation, & is available if u have the means to take advantage of it.

The em radiation is to some extent a minor form of electric energy in its own right, but em radiation is mainly a form of transmission of electric energy. If u tap into this em radiation then u can extract electric energy from the wire, where the major part of the electric energy lives.

The human body can't readily tap into the electric energy on the wire via the em radiation. We have to touch the wire. Even then we can't readily extract much electric energy (ie get a big shock). To get a big shock we have to also touch the ground, or another wire.

Derek & Dave & Nick & Mehdi & Brian & Bob & Co are all wrong.  Electric energy is in or on (i say on) the wire.
« Last Edit: April 29, 2023, 10:57:10 am by aetherist »
 

Offline T3sl4co1l

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Mains transmission lines carry the superposition of a multitude of wavefronts.  Each increment of wave energy is imperceptible, and most of them cancel out, hence why little power flows until a load is connected, and even then only what the load needs, not the full, whatever, 120V / Zo (which for romex is ballpark 100 ohms) that a single full-step wavefront would deliver.

Waves are indeed perceptible, but they need to be much more intense: ESD for example.  The spark from touching a grounded object propagates over and through your body, near the speed of light, giving a risetime of some nanoseconds.  The peak power is in the megawatts, enough to ionize air (hence the spark), and some skin around the contact area (not enough to notice from single hits, but the burn from multiple hits can be particularly destructive, e.g. RF burns).  Over a longer time scale, as things settle down, the charge delivered by this pulse causes ionic separation/motion in your tissues -- evident as the intense pain and sudden movement as it affects your nerves and muscles.

The human body in general is rather insensitive to electromagnetic fields, actually.  Fortunately, I guess.  Aside from visible light of course, and from frequencies low enough to affect the nervous system directly (<kHz) -- which by their nature, are almost impossible to carry through air alone, and need some contact to deliver real charge.

Note we can reduce the transient model to an average equivalent at low frequencies.  And here, it simply suffices to note that, the capacitance between say your finger and the wires in a piece of romex, is a couple pF at most, and at 120 even 240V, is just some microamperes, well below sensitivity threshold.

Tim
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Online RJSV

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Took College course, along those lines.
Please also see 'Fields and Waves in Modern...Electronics'
By Winnery and Van Duzer.  (spell check!)
   It is more advanced than I can handle, fully, but in catagory, of, like 90 % beginning and medium level physics.
   The main gist, of any energy flow, by itself without conductor, is a kind of 'chasing own tail' dynamic:
The changing electro field causes, or generates, a resulting changing magnetic field. That then continues, as that changing magnetic field, in turn creates a changing electric field.
That perpetuates, and all the 'Maxwell's equations' describe that, in calculus 'rates' of change, 'd X /dt',
for the two field types. That, of course, relating directly to 'c', the standard speed of light.   Light waves being EM waves, of course.
You could, I guess, say that the 'magnetic field is time-varying, this inducing an electric field.'
Then, just say 'This field pushes electrons, in the nearby conductor. Nearby insulation, not so much resulting flow, (from the e field).
Ok, then just say "That new electric current then, being time varying, will cause a NEW magnetic field, to expand around the insulated conductor."
That gets you to perceive the continuous, remake of those EM fields, that's the 'propagation' over nearby distance, all happening at light-speed.
 

Online RJSV

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I almost have it right. As some others here, are almost correct.
   I'd have to say: That the energy is partially held, in the wire, by the current , let's say it comes from 1 MHZ signal generator, 1 volt pk to ok. As that goes down the wire, as mentioned, d V/dt causing d u/dt (magnetic), causing, yet more d V/dt, in circular fashion, I think that cyclically, the energy IS not right in the wire, but soon will be. Looking at one single point, you observe the wax and wane, SINE shaped voltage wave, moving past your sample point.  Plus with magnetic sensor a similar SINE wave, I believe 90 degrees offset, (hypothetical 1 Mhz).
  However, energy does not travel speed of light, when carried by a cable, coax or twisted pair...EM speed is something like 70 % of 'c'.
I guess, that slower speed is a kind of phase-lag, as the free space EM wave has to charge up each little segment if the cable, as it goes...but that's not a professional talking.
   The experts talk, also, about 'phase' velocity vs wave speed...way over my head and pay scale.
 

Offline typoknigTopic starter

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So then, what is energy? ;D

This is the question I was hoping we would get to.  I propose that we cannot get shocked unless some "energy" is being transferred to/from us.  Since we don't get shocked unless we touch a bare conductor there must be some "energy" in or on the conductor.  What is that "energy"?   :-//
 

Offline TimFox

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Birds perched directly on a single overhead wire from a utility pole do not get shocked.
The phenomenon of being "shocked" results from current flowing through the body.
In my MRI days, I spent time in very strong static magnetic fields, between 0.5 T and 20 T (5 kG to 20 kG).  (The earth's magnetic field is < 1 G.)
(The common procedure was that the physicist should volunteer to be in the magnet while the engineers did the adjustments and ran the tests.)
The effect of these strong fields was evident:  I once set a tweezers down on the couch and it went flying into the bore.  The techs were forever finding paper clips that had been carelessly left behind.
When locating a non-ferromagnetic object (aluminum box with brass screws) near the magnet, the reaction force from eddy currents when the box was moving could be felt easily.
Besides the effect of these strong fields on ferrous object (such as surgical implants), the main safety worries were the E-field induced in the patient by the time-changing gradient magnetic fields used for imaging, and the high-frequency currents induced in the patient's conductive material (basically, saline solution) from the pulsed RF magnetic field that dissipated heat in the tissues.  In extreme cases, where a defective RF coil structure focused the AC field, this could cause a burn.  Of course, an extreme failure of the hardware could result in a direct connection to the patient and shock him, but this is extremely rare.
 

Offline eti

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This, AGAIN?  :-DD :-DD
 

Offline aetherist

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So then, what is energy? ;D 
This is the question I was hoping we would get to.  I propose that we cannot get shocked unless some "energy" is being transferred to/from us.  Since we don't get shocked unless we touch a bare conductor there must be some "energy" in or on the conductor.  What is that "energy"?   :-// 
Electric energy near a wire is 3 things.
(1) It is the energy in the em radiation surrounding the wire. We don’t know what this em radiation is, but it produces an electric force (due to what we call charge), & it produces a magnetic force (a mmf). It gives us radio waves.
(2) It is the energy of the(negatively charged) elektons on the wire, ie photons hugging the wire. These elektons can produce a force directly (ie by contact), or indirectly via their em radiation. Strictly speaking there is no such thing as contact, contact is via em radiation.
(3) It is the energy of the electrons on the surface of the wire.
Forces give us energy, & energy gives us forces.

Aether gives us photons (the fundamental particle)(or quasi particle)(electrons & quarks etc being the fundamental particle if u like), & the em radiation emitted by photons. Photons etc are an excitation of aether.
Praether is the fundamental essence, & it gives us aether (an excitation of the praether).
Everything that we see & feel has mass.
Except gravity, gravity aint got no mass. Gravity is due to the acceleration of the bulk flow of aether, aether flowing into matter (where aether is annihilated).
If something annihilates aether then that something has mass, & everything annihilates aether (ie everything has mass)(except that gravity has zero mass)(unless u believe in a contractile aether, but i wont go into that).

Em radiation has mass, photons have mass, electrons & elektrons &  elektons have mass, if not then we would not have electricity or elektricity or elekticity, ie we would not have electric forces, ie we would not have electric energy.
However, gravity & gravity force, & gravitational energy do not play a part in electric energy.
« Last Edit: April 29, 2023, 10:59:17 am by aetherist »
 

Online Someone

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This, AGAIN?  :-DD :-DD
Feels like it started off ok, but will quickly turn back into :horse:
 

Online RJSV

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So...Is there a textbook / Univ. Course available, describing 'aether', as I am ignorant, there.
Or, if it's controversial, what dynamic exists ? Unfair established physicists ?  Any medical implications, that folks don't usually hear about ?

   I'm just saying...(That's the kind of reactive comments I've gotten.  I just tolerate it...I'm flawed too.)
 

Offline aetherist

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So...Is there a textbook / Univ. Course available, describing 'aether', as I am ignorant, there.
Or, if it's controversial, what dynamic exists ? Unfair established physicists ?  Any medical implications, that folks don't usually hear about ?

   I'm just saying...(That's the kind of reactive comments I've gotten.  I just tolerate it...I'm flawed too.)
Aether aint gonna change anything much. But aether might help to explain things, & it might help with new discoveries, inventions etc.

The aetherwind plus my elektons explains why the speed of elekticity along a wire varies with direction (due to the aetherwind)(the aetherwind is 500 km/s, ie c/600). Photons (eg elektons) propagate at the speed of light in the aether, hence a photon (& elekticity) will have a speed of c+V or c-V for a tailwind or headwind.

If an aether then no STR, & no GTR (or most of it). But i don’t know of any uni course that considers that aether is real. They come close, ie when they talk of quantum foam, or dynamic space etc.
« Last Edit: April 29, 2023, 11:00:46 am by aetherist »
 

Online RJSV

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   Sorry, but I'm relegating this, into the
'Tolerance Folder'.  You can't waste my time, and others ('eti' also expressed that, approx.), with your narrative relating to Physics, in ABSENCE of any other reference text, reference credentialed professor, reference diagrams, ANYTHING.
   I admit, My presentations are bad, partially, but: Did anybody make suggestions, before ?  I mean, that got ignored?

   Because, short of any more reading your dialog, I'm outa here¥
 

Offline T3sl4co1l

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   Sorry, but I'm relegating this, into the
'Tolerance Folder'.  You can't waste my time, and others ('eti' also expressed that, approx.), with your narrative relating to Physics, in ABSENCE of any other reference text, reference credentialed professor, reference diagrams, ANYTHING.
   I admit, My presentations are bad, partially, but: Did anybody make suggestions, before ?  I mean, that got ignored?

   Because, short of any more reading your dialog, I'm outa here¥

"Aether" is a disproven hypothesis positing that the universe has a unique reference frame, and thus effects carried by that medium -- electromagnetism, or maybe gravity too, sure why not* -- show effects with respect to it.  This was a very reasonable supposition at the time -- wave mechanics were well known in the study of matter-based media, i.e. acoustic waves, gravity waves, etc.  In these phenomena, waves move with respect to the stuff of the medium itself, thus e.g. waves on a flowing river propagate faster (with respect to stationary ground) in the direction of flow.  Put another way: you get a Doppler effect all for free, when the medium is in relative motion.

*Aether predates relativity, but if they had known of gravitational waves at the time (or, really just been hinted at the possibility of such -- it's not much of a leap to suppose gravity might be carried by waves too), they'd have probably lumped it in as well.  Now, whether gravity has its own aether or is in fact the same as EM, wouldn't be so easy to determine given the information at the time.

EM aether theory was soundly considered disproven, after a series of experiments using interferometry to measure this supposed Doppler shift, gave a null result to extremely tight bounds: a modest fraction of the tangential velocity of the Earth.  Since the Earth is constantly in non-inertial motion (i.e. rotation on its axis and orbit), we should have no expectation that any particular time of day or year shows a consistent aether current with respect to it; and yet the observation was zero in all cases, no periodic change.

By this time (early 1900s), Einstein introduced Relativity; which, if you like, describes a kind of "aether", but one that is relative to any observer, specifically excluding any sort of unique or universal frame of reference.  A medium we today call spacetime.  Perhaps you could rescue "aether" by saying it's drawn along by any matter doing the observing, but that's quite a stretch.  Whereas the field equations are fully described and complete: as simple as can be, but no simpler.

Alternately, in the context of field theories, the field itself is a particular property of the universe, carrying waves of that particular type (i.e. EM waves, electron waves, quark waves, etc..), and coupling to other fields.  In a sense, these could be considered "aethers", and it turns out we have not one but many, one for each fundamental particle.  But this is, again, severely straining the usual meaning of "aether", and hence we call them what we do today -- particle fields.  These of course obey relativity (no special frame of reference, Lorentz invariant), at least the ones incorporating it such that they can.  (For example, you can take bog-standard quantum mechanics, which does not; but rolling in SR, and quite a lot of work later, you get QED, Quantum ElectroDynamics, a theory which describes to essentially exactness, essentially all of our everyday experience.  Adding the weak and strong fields, with their corresponding particles, and you get basically the Standard Model as we know it today, accommodating everything from atom smashing in particle accelerators, to neutron stars, and the first vanishingly small timesteps since the Big Bang.  It only leaves out GR, which has so far proven a tough fit with traditional field theories, and so mostly sits alongside on its own, in the Standard Model.)


I don't know (or care, frankly) if this [historical aether theories] is what aetherist is trying to promote here, but I agree with the conclusion that it is likely not worth ones' time.  (Or if you've properly set this thread on ignore, then consider this an FYI for all you other readers who should happen upon this thread. :) )

Tim
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Electronic design, from concept to prototype.
Bringing a project to life?  Send me a message!
 
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Online RJSV

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Wow, thanks for spending that detailed time!
  I wasn't aware I could put a block, on a THREAD, that's a useful item.

   Blown away, by the HISTORY and expertise, thanks Dave, and Tim.
 


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