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  1. #1
    Garry Blankenship's Avatar
    Garry Blankenship Guest

    Default Legal Disconnect ?

    Apologies on no photo yet, but uploaded all to a storage site, erased my disc and cannot figure out how to get it from there to here. I did a commercial job yesterday with three AC roof top units w/ relatively small round thumb/finger nobs for disconnects. My personal hard drive is telling me that a legal equipment disconnect must physically open all the power / legs / phases. An electro-magnetic or a control device that drives a contactor does not fullfill that requirement. These little nobs are roughly 1" to 1 1/2" in diameter and I see no way they could physically break the supply lines. Yet that is the only disconnecting means available. I must be mistaken about these, but need help.

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  2. #2
    Robert Meier's Avatar
    Robert Meier Guest

    Default Re: Legal Disconnect ?

    Sounds like a push button type stop switch that would be used to interrupt the control circuit to shut down the units. These were used decades ago in lieu of larger disconnects since they only required two wires and a small enclosure. They are no longer permitted as a required disconnecting means since they only interrupt the control circuit. A photo would help.


  3. #3
    Join Date
    Dec 2007
    Location
    Chico,Ca
    Posts
    423

    Default Re: Legal Disconnect ?

    If it is a Europeon style rotary disco w/ a means to lock it in the open postion, & listed by a NRTL, (UL, FM, or other firm) for the location, there is nothing wrong w/ that type......

    Now, if it is a selector switch wired into a control circuit, NO FREAKING WAY! It does not qualify as a disco.

    Photos to follow.

    The following disconnect switches have means to lock out, & have cover interlocks.



    Allen-Bradley 30A, 600V non-fusible disco.



    Unknown mfg from retired hood control panel.



    Allen-Bradley selector switches.

    Last edited by Rollie Meyers; 04-14-2012 at 06:14 PM. Reason: Added photos.

  4. #4
    Garry Blankenship's Avatar
    Garry Blankenship Guest

    Default Re: Legal Disconnect ?

    Thank you Rollie. They are very similar to the first two photos you provided. They are what I call thumb switches. The possible difference from your first photo is that the loads involved are 50 and 60 amp three phase, 208 volt loads. Those loads are to big IMHO for a switch that size to physically break all lines, unless it only breaks a control circuit which would not be legal, I believe. I am stll trying to get my photos back from Shutterfly, but there are some English as a second language challenges.


  5. #5
    Join Date
    Dec 2007
    Location
    Chico,Ca
    Posts
    423

    Default Re: Legal Disconnect ?

    Those rotary disconnects are avail in larger ampere ratings, if they are sized correctly there is nothing wrong w/ them as a disco.


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