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  1. #1
    Join Date
    Mar 2009
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    239

    Default Wiring in same joist bay as heating pipes

    I have new wiring run in the ceiling and the only option was to have 3 feet of the run in the same joist bay as 6 feet of 2 radiator pipes.

    The previous knob and tube wiring was run in this same way except the old wire was 2 conductors, each at 1 inch away from the pipes. The new wiring is 2x12ga @ 20A and 1x14ga @ 15A which are 6 inches away but I can assume it will have some heat impact being enclosed in the same joist bay. Any recommendations or do I have to somehow get the wiring redone? I was already thinking about fiberglass pipe insulation but i'm not sure if it will be enough to solve any heat issues.
    My advice and opinions come from hands on knowledge...and This Old House Hidden Content

  2. #2
    Join Date
    Jun 2007
    Location
    Fayette County, Ohio
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    5,942

    Default Re: Wiring in same joist bay as heating pipes

    Insulation on Romex cable is rated at 600 degrees. I Doubt the temp in the bay will be as excessive as you think especially if you have hot water heat.

    Jack
    Be sure you live your life, because you are a long time dead.-Scottish Proverb

  3. #3
    Join Date
    Dec 2011
    Location
    Cressona, PA
    Posts
    4

    Default Re: Wiring in same joist bay as heating pipes

    Quote Originally Posted by JLMCDANIEL View Post
    Insulation on Romex cable is rated at 600 degrees. I Doubt the temp in the bay will be as excessive as you think especially if you have hot water heat.

    Jack
    Insulation on Romex is NOTrated at 600 degrees. It's rated at 90 degrees Celsius. Which translates to 194 degrees Fahrenheit.

    If your boiler is set less than 190F, There should be no problem.

  4. #4
    Join Date
    Jun 2007
    Location
    Fayette County, Ohio
    Posts
    5,942

    Default Re: Wiring in same joist bay as heating pipes

    Quote Originally Posted by Justin Smith View Post
    Insulation on Romex is NOTrated at 600 degrees. It's rated at 90 degrees Celsius. Which translates to 194 degrees Fahrenheit.

    If your boiler is set less than 190F, There should be no problem.

    Justin is correct, I garbed the voltage rating in error.

    Jack
    Be sure you live your life, because you are a long time dead.-Scottish Proverb

  5. #5
    Join Date
    Jan 2011
    Location
    Columbiana, Alabama
    Posts
    794

    Default Re: Wiring in same joist bay as heating pipes

    The OP didn't say if the wiring and hot pipe were installed in a vented cavity or totally enclosed.

    Wiring has long been subjected to derating, due to ambient temperature, much less than 190 deg.

    At the very least I would insulate the pipe and attempt to ventilate the wire. But if the pipe stays hot for long periods of time (as I suspect it does) even the insulation/ventilation may not help.

    The best solution IMO would be separation.

    Good Luck from Columbiana, Alabama
    Maurice Turgeon,http://thesemi-retiredelectrician.com

  6. #6
    Join Date
    Mar 2009
    Posts
    239

    Default Re: Wiring in same joist bay as heating pipes

    The space will be enclosed once the drywall goes up on the ceiling. The only airflow will be little if any between holes and notches in the joist from old plumbing. One end of the joist cavity goes above the basement stairs which I can remove so air will flow in but i'm not sure if that helps.
    My advice and opinions come from hands on knowledge...and This Old House Hidden Content

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