Global War on Terror 8 - Winter is Coming

[The Sicatoka]

Re: Global War on Terror 8 - Winter is Coming

E&M is a subject I simply cannot wrap my head around, ...

The first step to understanding E&M is understanding what it really stands for: enigma and magic.

I was hit by lightning once, sort of: I was driving a tractor out in a field, chisel plowing, so I had a pretty good ground path. A relative was coming out to pick me up for the night and I could see them from two miles away. A storm was rolling in and there was lightning off in the distance. I saw the flash. The tractor engine (a big diesel) hiccuped, my climate control system stopped, my instrument cluster told me some interesting things for a second, and my radio died. I got to the end of the field and shut down to hop in with my ride. They were hysterical -- they saw the lightning had struck the cab and traveled down, around the cab, to the frame, to the drawbar, and to ground via the chisel plow. I was unhurt because was wasn't touching the path of electricity.

For that same reason, if you're ever in a car and a power line falls on the car STAY IN THE CAR! If the lines are still live the shell of the car is electrified, but the electricity (the negative charges) repels itself and will stay on that outermost conductive path - the car body. So don't open the door and end up touching the car (with your foot on the ground, i.e. the conductive path through you).

Personally, in a lightning storm, I'd prefer something far more conductive, and taller, than me be the well grounded thing. I have lightning rods on my house.

 

[Wisko McBadgerton]

Re: Global War on Terror 8 - Winter is Coming

I've never understood this, and I've had it explained to me a trillion times. The damage comes from electricity flowing through me, right? But grounding is connecting me to something that connects to ground, right? So doesn't that make the electricity want to run through me to reach ground?

I understand wanting to be insulated to isolate me from the electricity. But I don't understand grounding. Please try to explain this to me in a way I can grasp. Warning: apparently this is not as easy as it should be.

E&M is a subject I simply cannot wrap my head around, and believe me with a EE dad I tried for decades not to feel like a complete disappointment. Everything else in physics is a breeze, but when you star throwing out amperes and wattage I have a .8 p* IQ.

* palin -- the SI metric unit for intelligence. 1 palin is defined as the intellectual capacity of a standard Møøse at 0 degrees Celsius.

If you're confused it's perhaps because your second sentence here is correct, and the third isn't in this context. Electricity always seeks the easiest path to the ground. So in other words, if you're standing in a puddle and grab onto a hot wire the electricity will flow through you and likely damage you. Conversely if you are holding on to a 20' copper wire that is buried 10' in the ground and touch that wire to the same hot source, the electricity will mostly bypass you and flow through the wire you're holding to the ground, leaving you undamaged. This is given that there's not extremely high current because current in parallel systems takes every available path inversely proportional to the resistance of the path, so a very high current source could still damage you even though you are quite a resistant path in that example.

So for example, proper grounding for a power worker in an aerial lift might include grounding the lift truck and bonding the lift basket he's standing in to the hot wire, as well as bonding the hot wire to the ground on the nearest tower, thereby providing two lower resistance paths for current to flow through than the worker himself is (who also insulates with gloves and rubber shoes).

The ultimate point here is that just sticking your head in the sand during a lightning storm is a terrible course of action.

 

[joecct]

Re: Global War on Terror 8 - Winter is Coming

Canada? Prince Edward Island? Wot!?

http://www.cbc.ca/beta/news/canada/prince-edward-island/pei-schools-evacuation-1.3772113

 

[Kepler]

Re: Global War on Terror 8 - Winter is Coming

So for example, proper grounding for a power worker in an aerial lift might include grounding the lift truck and bonding the lift basket he's standing in to the hot wire, as well as bonding the hot wire to the ground on the nearest tower, thereby providing two lower resistance paths for current to flow through than the worker himself is (who also insulates with gloves and rubber shoes).

If I am understanding you, "I am grounded" is an assertion of a negation, equivalent to "I am not part of the least resistant circuit for the electricity to flow through." It is analogous to "I am concealed" meaning "there is no direct line of sight to me."

If so, you've just done what nobody in a trillion tries could do. So, um, thanks.

 

[Kepler]

Re: Global War on Terror 8 - Winter is Coming

Canada? Prince Edward Island? Wot!?

http://www.cbc.ca/beta/news/canada/prince-edward-island/pei-schools-evacuation-1.3772113

It's a promo for the new novel, Anne of Green Gables Gets Radicalized.

 

[Wisko McBadgerton]

Re: Global War on Terror 8 - Winter is Coming

If I am understanding you, "I am grounded" is an assertion of a negation, equivalent to "I am not part of the least resistant circuit for the electricity to flow through." It is analogous to "I am concealed" meaning "there is no direct line of sight to me."

If so, you've just done what nobody in a trillion tries could do. So, um, thanks.

Essentially, yes. As long as you include the notion that the least resistant circuit exists. And this is sufficient for things like household current provided you understand you can still be the least resistant path if there is no other good one. (i.e. don't just grab onto a hot wire as somewhere around 50 volts can be enough to overcome your resistance and go to ground through you, given no better place to go.) The main purpose of a (the third one) ground wire in a hand held drill, for example, is to provide a path of very small resistance compared to you in the event of a short circuit.

For things like transmission lines or lightning it gets more dicey of course, as the sheer amount of power can possibly overcome your resistance despite other paths among other problems. Like melting your ground wires off before melting your face off.

 

[Kepler]

Re: Global War on Terror 8 - Winter is Coming

Essentially, yes. As long as you include the notion that the least resistant circuit exists. And this is sufficient for things like household current provided you understand you can still be the least resistant path if there is no other good one. (i.e. don't just grab onto a hot wire as somewhere around 50 volts can be enough to overcome your resistance and go to ground through you, given no better place to go.) The main purpose of a (the third one) ground wire in a hand held drill, for example, is to provide a path of very small resistance compared to you in the event of a short circuit.

For things like transmission lines or lightning it gets more dicey of course, as the sheer amount of power can possibly overcome your resistance despite other paths among other problems. Like melting your ground wires off before melting your face off.

I get all that. What I've always been confused by is that you want to be grounded to avoid shock, yet a lightning rod is grounded. I would think one of those should be the opposite since the idea is to avoid being the electricity Fast Pass.

 

[FreshFish]

Re: Global War on Terror 8 - Winter is Coming

I get all that. What I've always been confused by is that you want to be grounded to avoid shock, yet a lightning rod is grounded. I would think one of those should be the opposite since the idea is to avoid being the electricity Fast Pass.

I'm not quite so sure that you personally want to be "grounded" as much as that you want whatever you are holding / using to be grounded. The idea is to have the current bypass you by taking a different path of lesser resistance.



Lightning rod is grounded to carry the current directly from the top of the building into the ground without traveling through the building itself, conducted by the ground wire to bypass the building.

 

[Slap Shot]

Re: Global War on Terror 8 - Winter is Coming

Wisko we will agree to disagree since nothing presented supports the claim, "This isn't true today" et al and in fact items that counter that claim have been adequately provided.

 

[Kepler]

Re: Global War on Terror 8 - Winter is Coming

I'm not quite so sure that you personally want to be "grounded" as much as that you want whatever you are holding / using to be grounded. The idea is to have the current bypass you by taking a different path of lesser resistance.

It is counter intuitive to me that I would want to be holding something grounded. I would think I want to be insulated from ground. If I'm in a car that is struck by lightning I'm OK as long as I'm not in contact with the frame of the car, correct? The car frame behaves like a Faraday cage and the lightning jumps from the bottom of the car to ground without "finding" me. But if I'm holding on to the door handle (or anyway something that's actually metal in a car these days) then I might be included in the circuit, so that's bad. Right?

 

[The Sicatoka]

Re: Global War on Terror 8 - Winter is Coming

As long as you include the notion that the least resistant circuit exists.

There's your assumption, the caveat, that was missing that caused me to not like what you were saying when this sidebar started.

 

[The Sicatoka]

Re: Global War on Terror 8 - Winter is Coming

It is counter intuitive to me that I would want to be holding something grounded. I would think I want to be insulated from ground. If I'm in a car that is struck by lightning I'm OK as long as I'm not in contact with the frame of the car, correct? The car frame behaves like a Faraday cage and the lightning jumps from the bottom of the car to ground without "finding" me. But if I'm holding on to the door handle (or anyway something that's actually metal in a car these days) then I might be included in the circuit, so that's bad. Right?

Yup. The electricity is just like charges in motion, and those like charges repel each other as they all try to reach ground. So the car body (not frame) is the cage and the electricity will stay on the car body (not come in) for that reason. It's a positive benefit of skin effect.

 

[Handyman]

Re: Global War on Terror 8 - Winter is Coming

Wisko we will agree to disagree since nothing presented supports the claim, "This isn't true today" et al and in fact items that counter that claim have been adequately provided.

Without a hardline definition of what terrorism is how can we judge either way? I didnt hear many people calling the white dude who killed a bunch of black people at a church a terrorist yet it isnt really all that different than what happened in St. Cloud.

 

[Kepler]

Re: Global War on Terror 8 - Winter is Coming

I didnt hear many people calling the white dude who killed a bunch of black people at a church a terrorist yet it isnt really all that different than what happened in St. Cloud.

Did he have a political or social cause? "Terrorism" just means murdering people is your loss leader: you're getting the press in the door to close the real sale.

 

[Wisko McBadgerton]

Re: Global War on Terror 8 - Winter is Coming

Wisko we will agree to disagree since nothing presented supports the claim, "This isn't true today" et al and in fact items that counter that claim have been adequately provided.

That is fine, but respectfully; The "This isn't true today" is supported by This Chart that I to linked before, which isn't MY chart but rather the one referred to in both the articles YOU posted about whitey killing more people than muslims. When those articles were written some 14 or 15 months ago, apparently that chart had whitey up 48-26. Today the score on the chart is 94-48 in favor of Muslims. Not to mention that the source counts 8 attacks since 2009 and only 2 between then and 2002. You can tell me it isn't accurate but it's the source YOU and the NEW YORK TIMES cited to me, and it says just what I said. More lately, less before.

 

[Wisko McBadgerton]

Re: Global War on Terror 8 - Winter is Coming

There's your assumption, the caveat, that was missing that caused me to not like what you were saying when this sidebar started.

Well, I was trying to keep this a simple concept to start with. We don't want Kepler unscrewing light bulbs and testing this stuff out at home, do we?


This is a pretty interesting example of a Faraday cage.

 

[Wisko McBadgerton]

Re: Global War on Terror 8 - Winter is Coming

Wisko we will agree to disagree since nothing presented supports the claim, "This isn't true today" et al and in fact items that counter that claim have been adequately provided.

Actually one more thing that sort of bothers me as I just trusted that you actually counted something when you posted this link:

According to this there have been no more deaths attributed to Islamic-backed attacks from 2009-present than there were between 2002-2009.

This is such a patently false claim based on the very link you provided I cannot begin to fathom how you came up with it. Here's the exact info from that chart listed as Killed-Injured-Date-Description. Red 7.5 years 2002-09 and Blue 7.5 years 2009-Present


2-4 Jul 2002 El AL ticket counter LAX
0-9 Mar 2006 Chapel Hill NC Vehicle driven into Pedestrians
1-5 Jul 2006 Seattle WA Jewish Federation
1-1 Jun 2009 Little Rock AR Army/Navy career center shooting

Total Killed 4 -- Injured 19



13-44 Nov 2009 Ft Hood Tx Soldiers Readiness Center
3-264 Apr 2013 Boston bombing
2-2 Apr 2013 Watertown Ma shootout
1-0 Apr 2014 Skyway WA shooting
2-0 Jun 2014 Seattle WA Nightclub attack
1-0 Jun 2014 East Orange NJ shooting attack
1-2 Sep 2014 OK City OK knife attack
1-3 Dec 2014 NYC NY axe attack
2-1 May 2015 Garland TX Shooting-art critical of Islam
6-2 Jul 2015 Chattanooga TN Military base attack
1-4 Nov 2015 Merced CA CAL knife attack
16-23 Dec 2015 San Bernadino shooting
0-2 Jan 2016 Philadelphia PA shooting
1-4 Feb 2016 Columbus OH machette attack
50-53 Jun 2016 Orlando Pulse nightclub
0-3 Aug 2016 Roanoke VA stabbing attack
1-10 Sep 2016 St Cloud MN stabbing
0-29 Sep 2016 NYC NY bombing
0-3 Sep 2016 Linden NJ bombing

Total Killed 101 -- Total Injured 452

 

[Slap Shot]

Re: Global War on Terror 8 - Winter is Coming

I must have screwed something up royally when I copied the chart to Excel, although I will say the St. Cloud attack for one wasn't there when I first looked. But nonetheless I clearly got it wrong. Regardless I still don't believe Trump is the answer on this front any more than Hillary.

 

[walrus]

Re: Global War on Terror 8 - Winter is Coming

Electricity always seeks the easiest path to the ground..

electricty takes any path to ground not just the easiest. If you are talking in your house type incidents, electricity isn't seeking ground its seeking a path back to the transformer.

 

[Wisko McBadgerton]

Re: Global War on Terror 8 - Winter is Coming

I must have screwed something up royally when I copied the chart to Excel, although I will say the St. Cloud attack for one wasn't there when I first looked. But nonetheless I clearly got it wrong. Regardless I still don't believe Trump is the answer on this front any more than Hillary.

Thank you and no worries.

And I'm fine with that. You and our good friend burd certainly have points about Trump's rhetoric, and how certain types of people react to it as it pertains to Muslims in general. On the other hand, Islam, not unlike Christianity in some ways, is fractured into many groups. Members of some of those groups, particularly those found in derivatives of Sunni Wahhibism, are committed to doing us (and others) harm. It is a problem as to how to discriminate against those specific individuals or groups, which we should, without discriminating against a larger community. I don't find a solution in simply saying "Islam is a religion of peace", as clearly all interpretations of Islam are not, or, "you're just racist" in wanting to keep certain individuals or specific group members far away, any more than I see an answer in the opposite of those tracks.