Totally not cool ...
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  1. #1
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    Exclamation Totally not cool ...

    ... <....> ... both figuratively ... and literally!

    Welcome to North East Texas summers. It's not too viscious yet, but the temps are hitting the low to mid 90s during the days, and getting down into the low 70s at night. However, 92~95F isn't exactly my definition of a picnic, much less a suitable environment for the house/office and computer room. Humidity runs between 60~90% too. Ergo, we use refrigerated air A/C. Swamp coolers don't help. They just make the hot and humid into hot and damp. <....>

    And ... when cooling the house, it just makes sense and is far more efficient to use 220V AC. I'll let you work out the math and efficiency curves to figure out why.

    All well and good ... until last Wednesday morning, when the big window unit let out a loud snap ... and quit.

    Diagnosing the problem wasn't hard. 120V across each leg to ground, but only .067V across the hot legs. The plug/breaker unit on it had gone south. However, the unit was under warranty, so I called the landlord to send someone to fix it. They came Thursday. Took most of the morning to snip off the plug/breaker, wire a cheap-azz hardware store 220 plug onto the pigtail, (thus pooching any remaining warranty) and wander away contented, whistling tunelessly. He looked no further for any indication of why the thing went out in the first place.

    Uh, huh. Ok. His choice, I guess.

    Inevitably, Friday morning, The big unit kicked on at around 78F, and started pumping out the heat. Five minutes later ...

    *Whump!* The unit quit dead cold. Then, loud enough I could hear it from inside and in the kitchen ...

    *Bbbbbrubvbvbvbv ... BZBZBZBZBZBZ-SIZZZZZZZZZLE! ... <....>

    Then ...

    WHAPPITY-SNAP!
    (from the outside service/breaker box under the service head.) <....>


    Naturally, myself and a 20 pound triple class Kidde immediately made for the door.

    Bottom line? No, the house didn't burn ... but it came a waaaaay too close for comfort. This ... is the remains of what I found in/of the outlet/junction box.



    Ayup. You're seeing right. That's an interior wall box, screwed to the outside (weather exposed) wall, routing ancient interior use 120V AC "romex" (with a rather puny 16 gauge "ground").

    Also note the left conduit is standard in-wall, and the right conduit (leading to another 20A 220V interior-use-only socket located around on the front of the building) ... is PVC.

    Uh, huh. <....> Sometimes it's easier to get forgiven than permission, so I nicked off the now roasted "new" plug, pulled the conduit, sockets et al off the wall, poked the existing cr...ud in the trash, and solid-wired the unit through new conduit into an exterior disconnect box and breaker like should have been done in the first place. Then I sacked up the stinky fried parts, and dropped them at the landlord's office with an estimated bill, and came back home to a much cooler (and safer) house.

    Lesson learned:

    Even if you're renting, sometimes it's a helluvalot safer to do some things yourself. <....>

  2. #2
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    Re: Totally not cool ...

    "Holy Smokes!" is all I can say!

  3. #3
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    Re: Totally not cool ...

    Glad you are OK. As for weather I am hoping the 90 degree and warmer days will stay away from Oregon this year. Right now it's 64F with showers.
    HP Notebook | AMD 7th Gen A6 4200 Dual-Core CPU - 2.0 GHz | 4 GB DDR4 RAM | 500 GB HDD | Radeon HD Graphics | Windows 10

    No fate but what we make...
    My Blog: kona0197.wordpress.com

  4. #4
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    Re: Totally not cool ...

    Only 95F? Brrr...

    http://www.aeronetworks.ca/2014/06/ramadan-kareem.html
    (That's 122F for you Yankees)

  5. #5
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    Re: Totally not cool ...

    50C ... That's just plain nuts! <....> Around here we call that a slow oven (for raising bread, slow cooking beans & brisket etc.).

  6. #6
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    Re: Totally not cool ...

    Even O'l John Fogerty only rambled about 110F:
    https://www.youtube.com/watch?v=jYguNCDfnCY

  7. #7
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    Re: Totally not cool ...

    True. But Texas has a "Hell" of its own.

    Quote Originally Posted by Author unknown
    HELL IN TEXAS

    The devil, we're told, in hell was chained,
    And a thousand years he there remained,
    And he never complained, nor did he groan,
    But determined to start a hell of his own
    Where he could torment the souls of men
    Without being chained to a prison pen.

    So he asked the Lord if He had on hand
    Anything left when He made the land.
    The Lord said, "Yes, I had plenty on hand,
    But I left it down on the Rio Grande.
    The fact is old boy, the stuff is so poor,
    I don't think you could use it in hell any more."

    But the devil went down to look at the truck,
    And said if it came as a gift, he was stuck;
    For after examining it careful and well
    He concluded the place was too dry for hell.
    So in order to get it off His hands
    God promised the devil to water the lands.

    For he had some water, or rather some dregs,
    A regular cathartic that smelt like bad eggs.
    Hence the deal was closed and the deed was given,
    And the Lord went back to His place in Heaven.
    and the devil said, "I have all that is needed
    To make a good hell," and thus he succeeded.

    He began to put thorns on all the trees,
    And he mixed the sand with millions of fleas,
    He scattered tarantulas along all the roads,
    Put thorns on the cacti and horns on the toads;
    He lengthened the horns of the Texas steers
    And put an addition on jack rabbits' ears.

    He put little devils in the broncho steed
    And poisoned the feet of the centipede.
    The rattlesnake bites you, the scorpion stings,
    The mosquito delights you by buzzing his wings.
    The sand burrs prevail, so do the ants,
    And those that sit down need half soles on their pants.

    The devil then said that throughout the land
    He'd manage to keep up the devil's own brand,
    And all would be mavericks unless they bore
    The marks of scratches and bites by the score.
    The heat in the summer is a hundred and ten,
    Too hot for the devil and too hot for men.

    The wild boar roams through the black chaparral,
    It's a hell of a place he has for a hell;
    The red pepper grows by the bank of the brook,
    The Mexicans use it in all that they cook.
    Just dine with a Mexican and then you will shout,
    "I've a hell on the inside as well as without."

  8. #8
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    Re: Totally not cool ...

    OK, that explains it. Spain didn't lose the war, they were happy to cede Texas to the crazy Yanks.

  9. #9
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    Re: Totally not cool ...

    Meah... typically residential. Wire probably lossened over the years, some corrosion too no doubt.., anyway I bet the heat came second in this case. Which means that box looked so for a long time and you learned about it only because something grounded. But yeah it looks to be 14 at best. Definately not 12.

  10. #10
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    Re: Totally not cool ...

    My guess would be initial contamination on one conductor, resulting in some oxidation, and then some rectification/resistance --> then more oxidation buildup --> more resistance --> thermal heating --> more resistance --> insulation burn-through --> voltage leakage --> thermal breakdown --> insulation cooks and crumbles --> conductors cross arc --> high current draw --> stuff melts --> breakers go ... ker-pow!

    The first fuse/breaker/failure indicator, was the factory plug/breaker. It obviously failed due to heating and voltage differential across the 120 legs. There was a nifty little melted plastic pit around one prong.

  11. #11
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    Re: Totally not cool ...

    That's what's neat: even loose lugs will generate enough heat to burn off both wire insulation and melt terminal blocks. Hmmm.., I guess what I really should be say is; yeah that's some dry kindling but, if you're inclined and with both aptitude and skill, then snugging up the connections to any other ~major appliance socket would be diligent. Just a quick survey ie., Some might say anal, I shrug and say preventive and we both know what thought did. O, and don't electrocute yourself.

  12. #12
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    Re: Totally not cool ...

    nice work with the air con. glad you avoided the house fire it could have been nasty.

    I just had some dodgy extractor fans to sort out at home. we just moved here and I am gradually sorting botched DIY issues like this. these fans were wired dangerously to the point they had heated the plastic shrouds and left black marks on the ceiling plaster. Needless to say rather than risk carrying using the damaged fans I got new ones.

  13. #13
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    Re: Totally not cool ...

    "Don't stick your finger in it!" -- What I Know About Electricity.

    That pic is Ugleee. Hope the landlord looked at it and contemplated his liabilities.

    Once was watching out the kitchen window during a nasty electrical storm when the transformer on a pole about 25 feet away blew up: Flash, bang, darkness.

  14. #14
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    Re: Totally not cool ...

    Dan, we've been approaching mid 90's - but mainly hanging in the 80's. And that's good enough for Summer heat.

    A couple years back, we had the Summer of 100F to 108F, with heat index of 115F - I'm guessing the Texas heat you get normally. No Thanks, and I do not want to have that again here in NC.

    Glad there was no fire. And I agree, I used to do a lot of repairs as a tenant - you know the quality of the repair, and some bucks knocked off rent
    On quest for blue smoke and red rings...

  15. #15
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    Re: Totally not cool ...

    Don't know how the house is safer when the underlying problem appears to be there still.

    The breaker didn't go off or at least there was no comment about it and it let the wires melt, anything connected to that breaker could be a time bomb I think.

    Correct me if I am wrong but doesn't the house circuit function like a foam cutter?

    e.g.:
    http://www.youtube.com/results?searc...utter+hot+wire

    You get 2 large buses aka thicker metal plates/wires and a thin wire running between then is the easiest circuit ever to build but demonstrates what happens in the house the thinner wire will heat up faster than the thicker ones and at some point melt if enough current is applied to it, to prevent that from happening one could put a fuse that would blow out before that or a breaker that is supposed to cut the current.

    So from what was said, the problem seems to be that the circuit breaker is passing a lot of current and the wiring is not capable of handling which could leads to melting of the insulation and eventual short and sissziling described, corrective measures would be to change the wiring to a thicker gauge aka bus, to handle more current or change the breaker to cut off at lower currents, or reduce the amount of wiring in that breaker (to reduce resistance and heat generated) and never plug a toaster in that one ever. no?

    Shorts don't just happen there is always a cause.
    Youtube: EXTREME WALL SOCKET SHORT OUT - CAPACITOR BLOWS UP IN KIDS FACE
    https://www.youtube.com/watch?v=DG4KIREsqE8

    Resources:
    http://hyperphysics.phy-astr.gsu.edu...ic/restmp.html
    http://www.alloywire.com/heating_element_design_1.html
    http://www.pelicanwire.com/uncategor...aw-calculator/
    Last edited by dobbi; 28th June 2014 at 03:55 PM.

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