220V dryer sparked on startup (3 wire) What to test?

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On 11-21-2013, 00:21, Wes Groleau wrote:

Clarification. You were apparently talking about lightning hitting a tower. I was referring to a downed transmission line. People have occasionally been killed or injured by having one foot closer to the downed line than the other foot.
As in taking a step towards it.

--
Wes Groleau

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On Wed, 20 Nov 2013 20:12:23 -0600, Nightcrawler® wrote:

Ah! Now it starts to make more sense! I was trying to figure that out and just couldn't.
I'm amazed at what you can tell just by looking at a panel. I see, well, I see 'stuff' - but you see AA, BB, etc.
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It is more familiarity and years of experience. Plus the knowledge of how things are supposed to work. The example you provided was beyond odd.
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On Thu, 21 Nov 2013 20:29:03 -0600, Nightcrawler® wrote:

It was from the PDF that was recommended earlier in this thread, for me to read, to understand how the power line transmission feed worked.
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On Wed, 20 Nov 2013 20:12:23 -0600, Nightcrawler® wrote:

Ah. Again, It makes sense! Even though those high-tension wires are insulated, they're carring hundreds of thousands of volts, so, electrons strip off and build up in the metal of the tower (were it to not be grounded).
At some point, that static electricity would be great enough to jump, like lightening, to anything that was grounded.
And, were that to be me, it would be like getting hit by a bolt of lightening.
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It is actually the potential voltage in the soil that is a hazard. One foot of linear distance may yield over 100,000 VDC. Humidity and wind play a part in this.
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Yes, that was evident from your first pictures. I meant, follow it the *other* direction to see where the *other* end attaches.
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On Tue, 19 Nov 2013 23:06:14 +0000, Doug Miller wrote:

Actually, it was not evident to me in the first pictures, but only because it didn't occur to me where to look.
So, if I follow the bare copper wire, in one direction, it clearly attaches to the neutral bar (along with a host of other ground-like things).
If I follow it in the other direction, that bare copper wire goes straight down into a rectangular hole where a few other wires go.
You can see the bare copper wire going straight down at the right of this picture:
http://farm6.staticflickr.com/5540/10951792723_46b5882ec1_o.gif
I can't follow that wire any farther, because it seems to be "in" the wall at this point; but I can say that a few feet directly below all this is the water pipe going into the house.
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Be careful not to extrapolate from this to subpanels. In a subpanel downstream of the service entrance, the grounded (neutral) and grounding conductors must _not_ be connected to the same busbar, and the grounded and grounding busbars must _not_ be bonded together, nor may the grounded busbar be bonded to the panelbox.
scott
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On Wed, 20 Nov 2013 15:35:24 +0000, Scott Lurndal wrote:

I saw pictures of that exact topic over here: http://www.hammerzone.com/archives/elect/panel/sub_panel/01/new.htm
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On Tue, 19 Nov 2013 02:59:57 +0000, Doug Miller wrote:

Well, that huge bare copper wire *must* be the main ground. It does go straight down, as you can see from this picture:
http://farm4.staticflickr.com/3682/10951717784_811820c6be_o.gif
But I can't tell where it goes from there. It is interesting to see all the rest of the wires go horizontally, except this ground wire, which goes straight down in the wall.
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Which, when you think about it, is a pretty good clue that it's going to be attached to something in the ground....

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On Tue, 19 Nov 2013 14:58:25 -0800, Oren wrote:

Yeah. I'm pretty sure it must be there but I can't see it.
I stuck my big fat head as far down the hole as my flashlight would allow me to see - but all I see are studs & spiders.
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On Tue, 19 Nov 2013 14:58:25 -0800, Oren wrote:

Allright. When you say Huckleberries, especially WWII Ufer Huckleberries, I have to take a second (and third) look.
The grounding rod, I believe, has been found! It was underneath a structure that was built over it; which I just removed to snap these pictures.
http://farm6.staticflickr.com/5533/10953698743_c7b082d70e_o.gif
I see what looks like two aluminum bare wires and two bare copper wires bolted to this steel rod driven into the ground.
Is *this* what we've been looking for?
http://farm6.staticflickr.com/5483/10953633824_a202b91783_o.gif
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On Tue, 19 Nov 2013 23:07:07 +0000, Doug Miller wrote:

I removed the enclosure that was built just under the meter panel and, lo and behold, all this *stuff* was directly below, one of which is a rod driven into the ground with four bare wires attached:
http://farm3.staticflickr.com/2892/10953538836_33326e6240_o.gif
I think that's the grounding rod, in the foreground, a few inches away from the concrete, slightly to the right of center.
That location is directly below the circuit panel.
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Yep. One of those wires goes back (should) to the neutral bus in your meter main.
Speaking of your neutral bus. The insulated white wire that looks burnt is not the wire causing the problem. It is the bare aluminum wire that goes underneath it that is cooking the insulation of the wire (burnt looking) above it.
I would recommend that the both be re-terminated using proper methods and materials.
First choice for a mechanical lug on the bus bar would be this:
http://tinyurl.com/mo9we7o
or similar part for your specific application. There should be a model number to verify/cross reference the part needed for your panel.
Second choice would be:
http://tinyurl.com/k7szg38
Both should be available at Home Depot. I believe your closest Home Depot is off of Hamilton Ave, though another one could have been built in the region since the last time I was in the area (Feb of 2007). If they are not available there, go to:
http://www.electdist.com/
They are the local Square D distributor. Not as cheap as Home Depot, but if you want a Square D item, they can get it for you. I would recommend trying to get lugs that have Allen head set screws. They give better torque and don't strip out as easily as the blade screwdriver types.
I also would recommend replacing all of the terminations of the large wires to the neutral bus with this type of set-up. Or, a satellite bus bar may be installed and jumpered over to the existing neutral bus using a mechanical terminal block such as:
http://tinyurl.com/kan3ep5
They have all kinds and E.D. (previous link) should have something that would work.
Primarily, hire an electrician so that everything checks out and make sure that no-ox is used on that aluminum at the termination points. That neutral cooking like that is not a good sign and hopefully it is only a bad termination and not a severe load imbalance.
Good luck.
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On Tue, 19 Nov 2013 21:19:57 -0600, Nightcrawler® wrote:

Interesting.
It makes sense that something *else* caused the scorching because if the wire that is scorched had itself gotten hot, the entire insulation would be burnt.
So,that means, as you noted, something *else* caused the scorching of the insulated wire.
There seem to be *two* bare aluminum wires that may be culprits:
http://farm6.staticflickr.com/5484/10951784553_afa8b636fc_o.gif
Looking closer at the pictures, it seems that someone might have "repaired" a smaller black wire at the same location (by wrapping tape around it?).
http://farm8.staticflickr.com/7392/10951790763_d01bc0a34e_o.gif
However, another (even closer) picture shows that the upper bare aluminum wire does not seem to have burned the insulation on the wire below it:
http://farm6.staticflickr.com/5535/10951789823_ffc7975152_o.gif
Here's a picture showing the *two* aluminum wires:
http://farm8.staticflickr.com/7325/10953807416_f38917aa93_o.gif
BTW, what on earth are the bare aluminum wires anyway? Are they huge grounds? Are they un-insulated neutrals?
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Now that I think about it, I got it backwards. The insulated wire is cooking the non insulated wire. So much for being tired and bleary eyed. The bare wires are grounds.
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On Tue, 19 Nov 2013 05:37:11 -0800, snipped-for-privacy@optonline.net wrote:

This was the biggest shock to me of all!
You are totally correct! I was wrong. Dead wrong.
That big fat copper wire is connected at EXACTLY the same place as all the white neutral wires are!
http://farm6.staticflickr.com/5516/10951789093_657e201b82_o.gif
For my entire life, I've thought they connected to the ground at different points. I never realized they connect to the ground at exactly the same point!
You can even see the neutral and ground wires of this cable which are both connected to the same steel strip!
http://farm4.staticflickr.com/3794/10951613376_89cfcb99fb_o.gif
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On Tue, 19 Nov 2013 05:37:11 -0800, snipped-for-privacy@optonline.net wrote:

I'm going to have to think about that one - so as to internalize it - but I did understand it as I read it.
BTW, in inspecting the breakers I noticed *this* breaker has no wire connected to it (the top right breaker in the picture):
http://farm6.staticflickr.com/5522/10951546945_ff8bf91e4a_o.gif
Am I to conclude that this is an unused "spare" breaker?
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