# What's with the new 4 prong dryer cords?



## Irishslave (Jun 20, 2010)

I Know it's required now, change cord, bar in dryer, recepticle, line, whole shootin match, but wondering why. black, red, white, green. OK. White denotes neutral. But there is no neutral on 220 per say right? Service coming to house is 2 hots and a ground right? Is neutral ground? I'm hoping to learn a little about bonding here and the purpose behind the extra wire here. In the panel your 110 lines white lines should go to the bar with incoming bond and bare cooper ones to the bar connected to external ground (waterpipe) right? Are these two bars connected together? It appears sometimes yes. So I guess break it down what's the difference between neutral and ground. arty:


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## 480sparky (Feb 1, 2009)

"Neutral' is technically the _ground*ed* conductor_. It is intentionally grounded, and normally carries current.

"Ground" is technically the _ground*ing* conductor_. It, too, is intentionally grounded, but only carries current during a fault situation.


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## Irishslave (Jun 20, 2010)

So the the extra leg on the new dryer plugs is just extra ground? I have been in the situation a couple of times when working the saw spins wildly like a rocket, lights get real bright etc. Always turns out to be a bad neutral. My guess here is current cannot alternate and becomes DC. Is that correct?


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## 480sparky (Feb 1, 2009)

No, not an 'extra ground'. There's a distinct difference between grounded and grounding.

Once carries current under normal circumstances (grounded, or neutral), the other (grounding, or ground) only carries current in order to open the over-current device (fuse or circuit breaker).

An 'open' neutral can cause voltages to fluctuate, how much depends on the loads impressed on the circuits. Don't know why you think AC can somehow become DC.


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## Irishslave (Jun 20, 2010)

OK I get it, fluctuating voltages as in 110 becoming 220 in the absence of a neutral. Which brings me back to no neutral in 220 right? The Old 220 circuits were 2 hot legs and a ground so I'm still confused being a non spark. Neutral carries unused current back to ground? I'm guessing that there was a saftey issue with the way it used to be done that was overlooked for a long time. I know this is required on hot tubs as well, which I personally will not hook up because of the grounding issues involved. I'm also guessing the path to ground must be foolproof to aviod electrocution


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## 480sparky (Feb 1, 2009)

Irishslave said:


> OK I get it, fluctuating voltages as in 110 becoming 220 in the absence of a neutral.


It doesn't automatically become 220 with the absence of a neutral. It may be 130/110, 139/101, 157/83, just depends on the load impressed on each side.



Irishslave said:


> Which brings me back to no neutral in 220 right? The Old 220 circuits were 2 hot legs and a ground so I'm still confused being a non spark. Neutral carries unused current back to ground?


Neutral carries the _difference_, not the unused.

If one side carries 15 amps, and the other 10, the neutral will carry 5. If it's 20 and 2, the neutral carries 18.

With two hot wires, with no neutral, you have a 240v circuit. Add a neutral, and it becomes 120/240v (dual-voltage) circuit.



Irishslave said:


> I'm guessing that there was a saftey issue with the way it used to be done that was overlooked for a long time.


It was generally done wrong for many years.



Irishslave said:


> ......... I'm also guessing the path to ground must be foolproof to aviod electrocution


Not to avoid electrocution, but to provide for the operation of the fuse/circuit breaker.


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## boman47k (Oct 13, 2006)

Hmm, I think all the neutrals and grnds are on the same bar. The bars on both side are married or connected, right?


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## 480sparky (Feb 1, 2009)

boman47k said:


> Hmm, I think all the neutrals and grnds are on the same bar. The bars on both side are married or connected, right?


At the main service, yes. Downstream from that, they are separated.


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## Irishslave (Jun 20, 2010)

OK It makes a lot more sense now. Also the controls would have to be 120v. the heating element is 240v the addition of neutral gives you 120/240volt dual circuit. So how many dryers burned up the old way? Or was there a neutral present somewhere in the older units for the controls? Thanks for making it clear, boy do I feel stupid now. But thanks to your knowledge I understand a lot more about the neutral now and it's function. Thanks again 480


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## 480sparky (Feb 1, 2009)

The old dryers used a 3-wire cord, which combined the neutral and ground together. It ended up being dangerous because if that conductor became 'opened', the frame of the dryer became energized.

Old 3-wire ranges are the same way.


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## boman47k (Oct 13, 2006)

480sparky said:


> At the main service, yes. Downstream from that, they are separated.


 
I may revisit this later. I am confused with the last sentence.


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## Irishslave (Jun 20, 2010)

480sparky said:


> The old dryers used a 3-wire cord, which combined the neutral and ground together. It ended up being dangerous because if that conductor became 'opened', the frame of the dryer became energized.
> 
> Old 3-wire ranges are the same way.


 And just think with a leaky washing machine right next to it, gives me the willys just thinking about it. This is why I don't like hot tubs 240 and water


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## 480sparky (Feb 1, 2009)

Irishslave said:


> And just think with a leaky washing machine right next to it, gives me the willys just thinking about it. This is why I don't like hot tubs 240 and water


Why the fear of water & electricity? 

Think about it. 

Electric water heaters.
Garbage disposals.
Dishwashers.
Ice makers.
Whirlpools.
Sump pumps.
Humidifiers.
Fish tanks.




And why 240 as opposed to 120? Voltage doesn't kill, current does.


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## Irishslave (Jun 20, 2010)

boman47k said:


> Hmm, I think all the neutrals and grnds are on the same bar. The bars on both side are married or connected, right?


 Yes I often see them mixed in the service panel, but around here on new services the inspectors like to see all neutrals on the right usually and all bare grounds on the left (seperated) It looks neater I guess


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## 480sparky (Feb 1, 2009)

Irishslave said:


> Yes I often see them mixed in the service panel, but around here on new services the inspectors like to see all neutrals on the right usually and all bare grounds on the left (seperated) It looks neater I guess



Then the inspector needs a little, uh....... 'education'.


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## Irishslave (Jun 20, 2010)

480sparky said:


> Why the fear of water & electricity?
> 
> Think about it.
> 
> ...


I ran the wire for a hot tub once for a friend 4 wire as required with remote disconnect but wasn't sure how to ground it. Drive rod at tub for external ground? I had him call over a pro not sure what he did. You are right about 120v being just as dangerous There are accidents at boat docks all the time around here


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## 480sparky (Feb 1, 2009)

Irishslave said:


> I ran the wire for a hot tub once for a friend 4 wire as required with remote disconnect but wasn't sure how to ground it. Drive rod at tub for external ground?


Ground rods are not for grounding, as odd as it sounds. The earth is a poor conductor, and any fault sent to a ground rod usually will not open the breaker/fuse. Only a properly-sized conductor back to the panel will pass muster.


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## Irishslave (Jun 20, 2010)

480sparky said:


> Why the fear of water & electricity?
> 
> Think about it.
> 
> ...


 I feel a little foolish yes as it it is raining on my window unit right now w/lightening now there is some real current


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## Irishslave (Jun 20, 2010)

Reminds me of one night during a storm the lightening blew the whip from a transformer to an overhead line the ark left was spectacular big and blue. I have also watched as lightening hit the building next to the roof we were on blow out a brick parapit and go horizontal across a big blvd right to a meter base and POW! Are these bolts just trying to find their way to ground through electrical systems or is it something else?


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## 480sparky (Feb 1, 2009)

Electricity, while extremely powerful, is also very lazy.... it will always try to take the path of least resistance. If that path happens to be electric wiring, metal plumbing lines, a golfer with spiked shoes swingin' a 9-iron............









..........or a telephone pole.............


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## Irishslave (Jun 20, 2010)

480sparky said:


> Electricity, while extremely powerful, is also very lazy.... it will always try to take the path of least resistance. If that path happens to be electric wiring, metal plumbing lines, a golfer with spiked shoes swingin' a 9-iron............
> 
> 
> 
> ...


 That was awesome! Have you seen the experiments where they try to create lightening from the ground up?


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## mrmike (Dec 9, 2008)

480sparky said:


> Ground rods are not for grounding, as odd as it sounds. The earth is a poor conductor, and any fault sent to a ground rod usually will not open the breaker/fuse. Only a properly-sized conductor back to the panel will pass muster.


I am a little perplexed by this- Then what are the ground rods for? No, Earth is not a good conductor but Earth is Ground where the path needs to go for a fault, Hence the ground rods. The conductor by itself will not suffice........... I agree it needs to be sized right-but if it doesn't burn open-it should trip the breaker.............as it is pretty instantanious...........


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## 480sparky (Feb 1, 2009)

mrmike said:


> I am a little perplexed by this- Then what are the ground rods for? No, Earth is not a good conductor but Earth is Ground where the path needs to go for a fault, Hence the ground rods. The conductor by itself will not suffice........... I agree it needs to be sized right-but if it doesn't burn open-it should trip the breaker.............as it is pretty instantanious...........



A ground rod or a ground field’s only purpose in life is to have a designed electrical path to dissipate a static discharge voltage (such as Lightning) to earth.
If you place a current probe around the conductor going to earth or the ground rod itself you should never see any current flowing on the conductor. If current is seen flowing on the conductor going to earth a ground fault exists. Another term that could be used is leakage current. In either case there is a parallel path back to the voltage source through the earth that crates the loop for current to flow on the earth ground conductor.
Current will always return to its voltage source.
AC will seek a path to the AC source, DC will seek a path to the DC source and a Static Discharge (Lightning) will seek a path back to its source usually earth. If a return path is not designed for that return path or multiple return paths exist current will seek its own paths back to its voltage source.


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## olligator (Nov 23, 2007)

did you say lightning? sometimes it needs some help finding its way back home too.

http://www.youtube.com/watch?v=_-A63oJo9pI


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## 480sparky (Feb 1, 2009)

olligator said:


> did you say lightning? sometimes it needs some help finding its way back home too.
> 
> http://www.youtube.com/watch?v=_-A63oJo9pI


Probably the coolest slo-mo lightning strike you'll ever see.

This one was shot with a real slo-mo camera, not some run-of-the-mill video slowed down artificially.


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## RH-Electric (Jan 16, 2010)

How 'bout some man made lightning? Here's a 3 phase switch that was opened while there was a load on one of the phases. The arc floats upward due to the heating of the air by the arc itself.


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## boman47k (Oct 13, 2006)

Do/can electrical charges ever jump to a person like that? Like working too close to a meter base?

I hate to show my ignorance. :shutup:


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## RH-Electric (Jan 16, 2010)

boman47k said:


> Do/can electrical charges ever jump to a person like that? Like working too close to a meter base?
> 
> I hate to show my ignorance. :shutup:


Not the kind of voltages you would find around a meter base. The voltages on the video are probably above 100,000 volts. The voltage around the average meter can't even cross 1/4" of open air. However, there is another very, very dangerous issue with the power at a meter socket: It is unfused. If you had a short circuit, the available amps, even at 10,000 amps of available fault current (among the lowest typically available) can do an unbelievable amount of damage.

I stab meters into live sockets all the time an am very cautious and am aware of what would happen if the meter went in at an angle and one of the top blades on the meter touched a line side of the socket and the metal of the enclosure at the same time. This type of accident is actually pretty hard to do, but it is do-able and the results would be catastrophic.


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## 480sparky (Feb 1, 2009)

RH-Electric said:


> ...........I stab meters into live sockets all the time an am very cautious and am aware of what would happen if the meter went in at an angle and one of the top blades on the meter touched a line side of the socket and the metal of the enclosure at the same time. This type of accident is actually pretty hard to do, but it is do-able and the results would be catastrophic.


Try one of these. :thumbsup:


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## RH-Electric (Jan 16, 2010)

480sparky said:


> Try one of these. :thumbsup:


Very cool! But at $140 that's gonna have to wait. Maybe for Christmas.. :thumbup:


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## Speedy Petey (Sep 30, 2003)

boman47k said:


> Hmm, I think all the neutrals and grnds are on the same bar. The bars on both side are married or connected, right?


Yes, but they serve VERY different purposes as 480 has explained. 
It's what the conductors do once they leave the panel that counts, NOT where they are connected to in the panel.


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## Speedy Petey (Sep 30, 2003)

480sparky said:


> A ground rod or a ground field’s only purpose in life is to have a designed electrical path to dissipate a static discharge voltage (such as Lightning) to earth.
> If you place a current probe around the conductor going to earth or the ground rod itself you should never see any current flowing on the conductor. If current is seen flowing on the conductor going to earth a ground fault exists. Another term that could be used is leakage current. In either case there is a parallel path back to the voltage source through the earth that crates the loop for current to flow on the earth ground conductor.
> Current will always return to its voltage source.
> AC will seek a path to the AC source, DC will seek a path to the DC source and a Static Discharge (Lightning) will seek a path back to its source usually earth. If a return path is not designed for that return path or multiple return paths exist current will seek its own paths back to its voltage source.


Excellent reply. :thumbsup:


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## 480sparky (Feb 1, 2009)

boman47k said:


> Hmm, I think all the neutrals and grnds are on the same bar. The bars on both side are married or connected, right?



Think of it this way: Take a look at most household sinks. While all of them have a drain at the bottom, many have a hole somewhere near the top.

Yet they both are connected to the drain line under the counter.............

Bathtubs have the same design as well.

OK, so they both end up at the same place, but they serve totally different functions. The hole at the bottom is to drain the sink, while the hole at the top edge is to (hopefully) drain enough water out to prevent the sink from overflowing.

So the electrician's neutral (grounded) is analogous to the drain in the bottom of the sink, while the ground (grounding) is similar to the overflow.


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## boman47k (Oct 13, 2006)

The downstream part was throwing me off. To me that is upstream or backstream. I guess I was hung up on power washing and soap dispensors on them. And the speration part. I understand the branch off. They go to seprate destinations.

Which reminds me, I noticed on my ground coming off my meter the is a ground/grounding wire clamped to the one going to the grnd rod, but it is only about 14" long and just hanging midair. A while back I was repairing the waterline going to the outside tap. While I was tightening the pipe under the house, I noticed the grnding wire attached to the pipe was wrapping around the pipe. Several rev's. I think I may have broken the wire. I hope I think to check it tomorrow. I think I will check for current just to be safe. :laughing:


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## 480sparky (Feb 1, 2009)

boman47k said:


> The downstream part was throwing me off. To me that is upstream or backstream. I guess I was hung up on power washing and soap dispensors on them. And the speration part. I understand the branch off. They go to seprate destinations.
> 
> Which reminds me, I noticed on my ground coming off my meter the is a ground/grounding wire clamped to the one going to the grnd rod, but it is only about 14" long and just hanging midair. A while back I was repairing the waterline going to the outside tap. While I was tightening the pipe under the house, I noticed the grnding wire attached to the pipe was wrapping around the pipe. Several rev's. I think I may have broken the wire. I hope I think to check it tomorrow. I think I will check for current just to be safe. :laughing:


I'd be lying if I said I understand any of that.


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## jkfox624 (Jun 20, 2009)

480sparky said:


> Probably the coolest slo-mo lightning strike you'll ever see.
> 
> This one was shot with a real slo-mo camera, not some run-of-the-mill video slowed down artificially.



I watched a show on discovery channel i think that had alot of real slo mo lightning. It was really neat to see how the bolt almost had feelers that reached out trying to find its way to ground.


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## boman47k (Oct 13, 2006)

480sparky said:


> I'd be lying if I said I understand any of that.


 
Whut? Whut part do you not understand???


Jk'ing. After reading it again, it may take me a little while to decipher it.


In short, I was saying I think I need to check the grounding wire that is attached to the waterline. I think I may have broken it while working on the pipe.


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## 480sparky (Feb 1, 2009)

boman47k said:


> Whut? Whut part do you not understand???........


And what does grounding have to do with soap dispensors?


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## boman47k (Oct 13, 2006)

Nothing. I said when I think of downstream. I think of a soap dispensor on a power washer. What I meant by that is when you said downstream, I was confused as to me downstream would be in the house somewhere in front of the service, not back toward the source or behind the service.

Upstream before the panel box, downstream from the panel box onward toward the interior of the house. I'm strange like that.

Hmm, I guess since the ground is the return path, from the panel to the earth and or water pipe would be considered downstream.

Just opposite of what I was saying.


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## 480sparky (Feb 1, 2009)

boman47k said:


> Nothing. I said when I think of downstream. I think of a soap dispensor on a power washer. What I meant by that is when you said downstream, I was confused as to me downstream would be in the house somewhere in front of the service, not back toward the source or behind the service.
> 
> Upstream before the panel box, downstream from the panel box onward toward the interior of the house. I'm strange like that.
> 
> ...


Gotcha.

Downstream and upstream are relative terms in electrical, just like on a map of a river.

Kinda like St. Louis is upstream from Memphis, but downstream from Minneapolis.


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## boman47k (Oct 13, 2006)

My head was begining to hurt. :laughing:


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## Irishslave (Jun 20, 2010)

is this thread still open?


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## 480sparky (Feb 1, 2009)

Irishslave said:


> is this thread still open?



I don't see it locked. :no:


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## Irishslave (Jun 20, 2010)

480sparky said:


> I don't see it locked. :no:


 I was just over at the more advice from home depot thread i would have thought that one would be lit. must be a lot of ball games on tonight. Work is very slow here so I have to keep the entertainment cheap


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## 15kv (Aug 20, 2010)

Not sure if was ever said ,but i believe the added neutral on dryer plugs is for the added electronics in dryers these days and in the future.


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## JumboJack (Aug 14, 2007)

480sparky said:


> Probably the coolest slo-mo lightning strike you'll ever see.
> 
> This one was shot with a real slo-mo camera, not some run-of-the-mill video slowed down artificially.


How slow is this?


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## Speedy Petey (Sep 30, 2003)

15kv said:


> Not sure if was ever said ,but i believe the added neutral on dryer plugs is for the added electronics in dryers these days and in the future.


The neutral was NOT "added". It was always there. 
Typically the controls and motor are 120v which is why a neutral is required. 
Electronics can and will run on 240v just as easily as 120v. 

The old circuits would allow the neutral to also serve as the ground. Not the other way around.
Newer circuits require a dedicated ground.


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## 480sparky (Feb 1, 2009)

JumboJack said:


> How slow is this?



10,000 FPS comes to mind.


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## 15kv (Aug 20, 2010)

A 4 wire dryer cord contains a black, red, white and green wire. The red and black wires are hot live wires and get connected to the 2 outer connectors on the dryers power terminal block, doesn't matter which is which as long as it is the outer two connectors. The green wire is a ground wire and gets connected to the frame of the dryer. The white wire is a neutral wire and must be connected to the center connector on the dryer power block. No ground strap is used in a 4 wire setup (grounded circuit). In the sample picture above the ground strap in folded over and is connected to the center connector but NO connection from it or jump to ground. The ground strap could also be removed if you wish as it is not needed in this installation.


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## bhock (Feb 17, 2009)

Speedy Petey said:


> The neutral was NOT "added". It was always there.
> Typically the controls and motor are 120v which is why a neutral is required.
> Electronics can and will run on 240v just as easily as 120v.
> 
> ...


This was always my understanding of it.


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## JohnJ0906 (Jan 7, 2007)

15kv said:


> A 4 wire dryer cord contains a black, red, white and green wire. The red and black wires are hot live wires and get connected to the 2 outer connectors on the dryers power terminal block, doesn't matter which is which as long as it is the outer two connectors. The green wire is a ground wire and gets connected to the frame of the dryer. The white wire is a neutral wire and must be connected to the center connector on the dryer power block. No ground strap is used in a 4 wire setup (grounded circuit). In the sample picture above the ground strap in folded over and is connected to the center connector but NO connection from it or jump to ground. The ground strap could also be removed if you wish as it is not needed in this installation.


Click for slide show


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## skyhook (Mar 17, 2007)

480sparky said:


> Electricity, while extremely powerful, is also very lazy.... it will always try to take the path of least resistance. If that path happens to be electric wiring, metal plumbing lines, a golfer with spiked shoes swingin' a 9-iron............
> 
> 
> 
> ...


This happened in my home town, Redmond, Oregon.


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## 480sparky (Feb 1, 2009)

skyhook said:


> This happened in my home town, Redmond, Oregon.


Lightning strikes everywhere and anywhere.


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## wbr (Feb 19, 2011)

RH-Electric said:


> How 'bout some man made lightning? [/youtube]


Some years ago I messed around with Tesla Coils.
Was fun and taught me some stuff.
Here's my coil then,now it's in pieces buried under other stuff :laughing:


























Edit- looks like I messed up getting the you tube to work here,
This is the link to a short video of it working;

http://www.youtube.com/watch?v=JZthqg--rkg


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## ameriserv (Apr 8, 2013)

Very nice!


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