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Thread: Saftey first

  1. #1
    Join Date
    Jul 2009
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    Zephyrhills Florida
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    79

    Smile Saftey first

    Be careful out there people, I just ran across a 3 phase rooftop unit with a single phase disconnect installed on it. Third leg was hot all the way from breaker down stairs right to 1 leg on compressor. Volts were everywhere and I was lucky I checked with meter before touching. Even more confusing was that unit used a single phase contactor which made it appear even more like a single phase that a 3 phase. Unit is wired correctly with new disconnect.

  2. #2
    Join Date
    Aug 2009
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    tn.
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    always check with meter i learned the hard way

  3. #3
    Join Date
    Mar 2004
    Location
    Grottoes VA
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    5,856
    I had a new install I was working on where an electrician did that to me. I was working late on a sat. to start the equipment up. I called the electrician right there and made them fix it, I wasn't waiting until Monday. He had to drive an hour to get to me.
    Karst means cave. So, I search for caves.

  4. #4
    Join Date
    Aug 2009
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    MT JULIET,TN
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    83
    Quote Originally Posted by jjust61 View Post
    Be careful out there people, I just ran across a 3 phase rooftop unit with a single phase disconnect installed on it. Third leg was hot all the way from breaker down stairs right to 1 leg on compressor. Volts were everywhere and I was lucky I checked with meter before touching. Even more confusing was that unit used a single phase contactor which made it appear even more like a single phase that a 3 phase. Unit is wired correctly with new disconnect.
    I always check each leg to ground,AT THE UNIT!,not only this,always Verify your meter is working at a known voltage soure.Not only will this save you the hassel of melted fillings,it just may save your life.Point being if your meter is having a bad day,odds are you will too!
    Anything worth doing,is worth doing RIGHT the FIRST time around!!!

  5. #5
    Join Date
    Apr 2007
    Location
    Kaufman county, Texas
    Posts
    10,168
    I always lift the lid and visually verify the contact arms pull out. I have seen about 6 or 8 over the years that are broken and do not actually disconnect all 3 of the legs.

  6. #6
    Join Date
    Sep 2009
    Location
    Covington, KY
    Posts
    159
    Verifying your meter on a known voltage source is important. Low batteries can KILL.

  7. #7
    Join Date
    Mar 2003
    Posts
    7,326
    a buddy of mine teaches for one of the locals, and also teaches the osha thirty course.......he jst cut off his thumb on a powersaw. oops.

  8. #8
    Join Date
    Jul 2006
    Location
    Anytown USA
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    2,060
    Quote Originally Posted by Tool-Slinger View Post
    I always lift the lid and visually verify the contact arms pull out. I have seen about 6 or 8 over the years that are broken and do not actually disconnect all 3 of the legs.
    I just had a brand new disconnect that had failed to open all 3 legs..

    Always check each leg to ground before touching any wires.. I also keep a lock in my tool bag to lockout a power source if needed.

  9. #9
    Join Date
    Feb 2005
    Location
    Barrie, Ontario
    Posts
    4,622
    A few years ago a competitor jumped one leg in an outdoor disconnect because it failed... Then they lost the contract to us.

    Found it before it killed anyone, but I never found the guy that booby trapped that one or else it may have caused a fatality afterall...
    Is this a Fabreze moment? C.Y.D. I'm voting white elephant. 2¢.
    My competition are my best salespeople!

  10. #10
    Join Date
    Jul 2000
    Location
    Middletown, Ohio USA
    Posts
    571

    NFPA 70e

    Don't forget your hardhat, faceshield, gloves, and flame-retardant clothing. You need to put those on before you shut the disconnect off. Then verify that all three legs are dead. Once dead, lock out the unit before servicing. And if you must troubleshoot with live electicity present, you must have all the gear on.
    See, the human mind is kind of like... a piñata. When it breaks open, there's a lot of surprises inside. Once you get the piñata perspective, you see that losing your mind can be a peak experience. ~Jane Wagner

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