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  1. #40
    Join Date
    Mar 2006
    Location
    Omaha, NE
    Posts
    11
    If you look at this and think about it, you could have the breaker closed, and the blade installed, and not trip the breaker until the contactor closed.
    The unit is isolated from ground due to the whip being car-flex. and the chance the lineset could be a feasible ground is questionable.

  2. #41
    Join Date
    Dec 2012
    Location
    columbus, OH
    Posts
    2,039
    Quote Originally Posted by danjohnson View Post
    If you look at this and think about it, you could have the breaker closed, and the blade installed, and not trip the breaker until the contactor closed.
    The unit is isolated from ground due to the whip being car-flex. and the chance the lineset could be a feasible ground is questionable.
    Read post 22 it did not short with the contactor closed. Apparently the line set and coil were not grounded.

  3. #42
    Join Date
    Aug 2012
    Location
    NE wisconsin
    Posts
    402
    Plastic pan and gromets on the lineset through the case and yeah, I could see the coil being isolated.

  4. #43
    Join Date
    Feb 2013
    Location
    north georiga
    Posts
    598
    how about when someone replaces an existing 3-phase unit with a new 3-phase unit and installs a single phase disconnect and wire nut the third leg together, 208volt service and it was the hi leg that they wire nut-ed. now that one hurt !!!

  5. #44
    Join Date
    Sep 2002
    Location
    Virginia
    Posts
    3,179
    Quote Originally Posted by davidj001 View Post
    how about when someone replaces an existing 3-phase unit with a new 3-phase unit and installs a single phase disconnect and wire nut the third leg together, 208volt service and it was the hi leg that they wire nut-ed. now that one hurt !!!

  6. #45
    Join Date
    Nov 2008
    Location
    DFW,TX
    Posts
    2,170
    wow thats why we should never believe a disconnect works and check with meter before grabbing.

    that usually kills a compressor, causes short to ground..

  7. #46
    Join Date
    Aug 2009
    Location
    Beatrice, NE
    Posts
    2,127
    I remember finding a 20kW air handler running direct off the lugs on the panel box, 200 A main was the only protection.

    I also remember getting bit off the 24v on a contactor I was changing, disconnect pulled. Checked and had 144v one side of the coil to ground. Tracedit back to a fan limit control that had been replaced but they never removed the jumper for the low voltage limit. Still don't know how it didnt' burn up the trans. or trip a breaker.

  8. #47
    Join Date
    Jun 2011
    Location
    Detroit vicinity, Michigan
    Posts
    79
    If you don't check power/try to start equipment after throwing the disconnect, You're gonna have a bad time....M'Kay?

  9. #48
    Join Date
    Aug 2009
    Location
    Maine
    Posts
    3,337
    Ok update. I am going to put my klien away and go back to the greenlee volt stick.
    Although the klien seems to be more reliable, my OLD ears can't hear it as well as the
    Greenlee.

  10. #49
    Join Date
    Feb 2013
    Location
    Lamar, SC
    Posts
    545
    Quote Originally Posted by philjafo View Post
    That's for an anti theft feature.
    X2
    "If you've eliminated all other possibilities whatever remains must be the truth."

  11. #50
    Join Date
    Dec 2012
    Location
    columbus, OH
    Posts
    2,039
    I recently bought a Milwaukee voltage detector on account of this thread. I dont trust it. It wont show potential across a light switch for some reason.

  12. #51
    Join Date
    May 2010
    Location
    Brooklyn, NY
    Posts
    99
    correct me if i am wrong, but if the disconnect is inserted, then it will automatically trip the breaker since the White wire is grounded at the unit. Assuming there's not flame spot around the grounded white terminal, the circuit was never live for once.

  13. #52
    Join Date
    Dec 2012
    Location
    columbus, OH
    Posts
    2,039
    Quote Originally Posted by EEAllen View Post
    correct me if i am wrong, but if the disconnect is inserted, then it will automatically trip the breaker since the White wire is grounded at the unit. Assuming there's not flame spot around the grounded white terminal, the circuit was never live for once.
    The fault circuit is being used as a neutral, the chassis that is connected to the hot wire has no path back to the breaker box untill some unlucky individual provides one.

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