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  1. #1
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    Default Burnt Thermostat Wiring

    Came across these burnt thermostat wires today. Has any one ever seen T-wiring burnt though as such. The wiring actually looked like it had been cut, but I can't figure out the burns on the wires.

    Any ideas?

    rick

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  2. #2
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    Default Re: Burnt Thermostat Wiring

    Rick,

    Any other evidence of a lightning strike?

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  3. #3
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    Default Re: Burnt Thermostat Wiring

    Couldn't find any sign of anything like that.

    rick


  4. #4
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    Default Re: Burnt Thermostat Wiring

    A typical thermostat circuit uses a 24 VAC low voltage transformer supply. The thermostat / heating controller may require 100 milli-amps to over 1 Amp.

    So, if the wires were cut there would certainly be enough current to arc and melt / burn the insulating coating of the cable.

    The short-circuit (instantaneous) (in mili-seconds) current can be in hundreds and even thousands of amps. Thus causing a lot of sparking and smoking.

    Fuse protection of the T-stat voltage may or may not be implemented.

    In my former career I tested medical device hardware and software... sometimes we intentionally short-circuited power supplies and sometimes it was a surprise test... arc smoke and fire. Nothing like a resistor or a power SCR burning up to clear out a lab.


  5. #5
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    Default Re: Burnt Thermostat Wiring

    Quote Originally Posted by Charles Smith View Post
    A typical thermostat circuit uses a 24 VAC low voltage transformer supply. The thermostat / heating controller may require 100 milli-amps to over 1 Amp.

    So, if the wires were cut there would certainly be enough current to arc and melt / burn the insulating coating of the cable.
    I've never seen one with enough power to spark that much, but could be.

    In my former career I tested medical device hardware and software... sometimes we intentionally short-circuited power supplies and sometimes it was a surprise test... arc smoke and fire. Nothing like a resistor or a power SCR burning up to clear out a lab.
    The problem is not the cut wires or burned up components, the problem is that you 'let the smoke out'. Any one around electricity knows that you can never 'let the smoke out', otherwise it will no longer work.

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  6. #6
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    gainesville fl
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    Default Re: Burnt Thermostat Wiring

    looks like there might have been a plumber on site.


  7. #7
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    Default Re: Burnt Thermostat Wiring

    Quote Originally Posted by Charles Smith View Post

    So, if the wires were cut
    Charles,

    Good theory but the wires are Rounded Over from being Burned.

    It Might have Choked Artie But it ain't gone'a choke Stymie! Our Gang " The Pooch " (1932)
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  8. #8
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    Default Re: Burnt Thermostat Wiring

    If that's thermostat, wire why do I only see one conductor?


  9. #9
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    Default Re: Burnt Thermostat Wiring

    Quote Originally Posted by Michael Larson View Post
    If that's thermostat, wire why do I only see one conductor?
    The way it arced through.

    Look at the top section of the conductor and you will see the twists inside the outer sheath from the other conductors within the outer sheath.

    My only problem with it being thermostat wiring and being cut did that is the arc flash was so hot that it bubbled up the outer sheath. The only way I can imagine that happening is if someone mis-wired something and put 120 volts (or even 240 volts) on that, in which case a cut could do that.

    Maybe the transformer went bad, was mis-wired, who knows - I sure don't.

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  10. #10
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    Default Re: Burnt Thermostat Wiring

    Quote Originally Posted by Jerry Peck View Post
    The way it arced through.

    Look at the top section of the conductor and you will see the twists inside the outer sheath from the other conductors within the outer sheath.

    My only problem with it being thermostat wiring and being cut did that is the arc flash was so hot that it bubbled up the outer sheath. The only way I can imagine that happening is if someone mis-wired something and put 120 volts (or even 240 volts) on that, in which case a cut could do that.

    Maybe the transformer went bad, was mis-wired, who knows - I sure don't.
    I did notice the twist.

    The copper looks awful shiny for having been exposed to an arc.


  11. #11
    James Duffin's Avatar
    James Duffin Guest

    Default Re: Burnt Thermostat Wiring

    The cable in the picture looks like the type of cable used by the power company when hooking up their load management equipment. I would be interested as where the cable terminated on each end.


  12. #12
    Michael Sierra's Avatar
    Michael Sierra Guest

    Default Re: Burnt Thermostat Wiring

    We had a similar situation happen to my inlaws, unfortunetly the issue caused a fie and the houes burnt down. It was a total loss but no one was hurt.

    In there case a contractor had remodled the kitchen and wired a thermostat incorrectly. This caused the unit to alway be on, it was a local under the counter heater. The constant heat caused the wire to over heat and burn. The wire looked the same at the edges but with out the cut


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