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Thread: Hot work on UPS equipment

  1. #11
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    check with the UPS manufacturer. You can't turn off the battery.

  2. #12
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    Quote Originally Posted by bravo69 View Post
    Ron, has OSHA code changed in the last few years? It was brought to my attention that hot work was allowed and now revisions say its not permitted. The UPS equipment supports life safety, PLC & Network cabinets. The life safety fire alarm system would be increased hazards and therefore hot work is permitted, correct?
    You can rationalize it any way you like to make it work in the way you want it to work.

    Although UPS batteries stay energized, hard to imagine that if it was turned off in the right conditions and timeframe, that it would be more hazardous to turn off than if you worked on it hot.

    There are often other ways around working it hot, depending on what system or connections you are working on. Generally bypass' or temp connections get rid of the need to what was considered in the past was a reason to work hot.
    Ron

  3. #13
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    Are you talking about just battery replacement or beyond that?

  4. #14
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    Since when can you turn off a battery/s? UPS = Uninterruptible Power Supply.
    Ken
    Electrical Project Coordinator


    "Communication, its a wonderful thing, when it happens."

  5. #15
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    Quote Originally Posted by ken44 View Post
    Since when can you turn off a battery/s?
    Since you can pull the battery disconnect? Most UPSs have them, well, pretty much every one I've ever touched does- might be a connector behind a panel, might be pulling the packaged battery trays out, might be a huge DC switch on the wall behind the UPS, etc.

  6. #16
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    Quote Originally Posted by ron View Post
    https://www.osha.gov/pls/oshaweb/owa...ARDS&p_id=9910

    1910.333(a)(1)

    "Deenergized parts." Live parts to which an employee may be exposed shall be deenergized before the employee works on or near them, unless the employer can demonstrate that deenergizing introduces additional or increased hazards or is infeasible due to equipment design or operational limitations. Live parts that operate at less than 50 volts to ground need not be deenergized if there will be no increased exposure to electrical burns or to explosion due to electric arcs.

    Note 1: Examples of increased or additional hazards include interruption of life support equipment, deactivation of emergency alarm systems, shutdown of hazardous location ventilation equipment, or removal of illumination for an area.


    Note 2: Examples of work that may be performed on or near energized circuit parts because of infeasibility due to equipment design or operational limitations include testing of electric circuits that can only be performed with the circuit energized and work on circuits that form an integral part of a continuous industrial process in a chemical plant that would otherwise need to be completely shut down in order to permit work on one circuit or piece of equipment.


    Note 3: Work on or near deenergized parts is covered by paragraph (b) of this section.

    I know this is an old thread but I have a question about this. 'Live parts to which an employee may be exposed' If I am working in a live panel, for troubleshooting purposes only, meters etc, and if everything in the panel is touch safe to the point that you would be unable to physically touch a line voltage terminal (with fingers or any other body part), would that classify the situation to a condition of where the employee would not be able to be exposed?

  7. #17
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    Quote Originally Posted by Aleman View Post
    I know this is an old thread but I have a question about this. 'Live parts to which an employee may be exposed' If I am working in a live panel, for troubleshooting purposes only, meters etc, and if everything in the panel is touch safe to the point that you would be unable to physically touch a line voltage terminal (with fingers or any other body part), would that classify the situation to a condition of where the employee would not be able to be exposed?
    It may possibly be considered safe from electric shock hazards, it may still present arc flash hazards.

  8. #18
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    Quote Originally Posted by zbang View Post
    Since you can pull the battery disconnect? Most UPSs have them, well, pretty much every one I've ever touched does- might be a connector behind a panel, might be pulling the packaged battery trays out, might be a huge DC switch on the wall behind the UPS, etc.
    You can disconnect a battery, but you can't turn it off. Take your car battery, for example. Disconnect the wires, and you still have two terminals, + and -. Drop something metal across them, and there'll be a big blue spark. Connect a bunch in series and drop something metal across them, and you'll get a bigger blue spark. Some of UPS battery plants can deliver 9,000A or more to a short circuit.

  9. #19
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    Quote Originally Posted by wtucker View Post
    You can disconnect a battery, but you can't turn it off. Take your car battery, for example. Disconnect the wires, and you still have two terminals, + and -. Drop something metal across them, and there'll be a big blue spark. Connect a bunch in series and drop something metal across them, and you'll get a bigger blue spark. Some of UPS battery plants can deliver 9,000A or more to a short circuit.
    Which means your arc flash hazard is possibly a higher concern then the shock hazard in some of those examples.

  10. #20
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    Quote Originally Posted by wtucker View Post
    You can disconnect a battery, but you can't turn it off.
    Are you working on the battery string or on the UPS? The OP asked about the UPS, and in almost all cases, you can disconnect the batteries from the UPS. If it's a packaged unit, like a Symetra, even the removable battery pack terminals are shrouded.

    I can't think of an UPS system than can't be completely de-energized with the exception of the battery string(s) themselves (and you can always remove a link in the string or lift a lead off the terminal).

    Be sensible about it.

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