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Thread: LO/TO

  1. #1
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    Piketon, Ohio, USA
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    LO/TO

    I have a LOTO question. Here is the scenario:

    We have a boiler that we are doing the annual PM on. The PM is done in two parts, the first part is performed under LOTO where the 480V is locked and tagged out. The second part requires the boiler heaters (480V) to be de-energized, but the 120V control power to be energized. It is checking the level gauges, and if the heaters come on, they will try to control the gauges instead of the controlled pressure being applied. For this, the 480V heater fuses are pulled (the cover is off, exposing the heater connections), and the LOTO removed. An EEWP is in place to allow the lifting and landing of 120V leads on the gauges and adjustment of a rheostat as needed.

    My question is, do the heater fuses need to be "controlled", ie, placed under LOTO.

    I think they do, but there are people arguing that since the fuses are not being pulled to protect personnel, they do not need to be under LOTO. But, if I do not control them, how to I ensure that a zero energy check is done on the exposed heater connections?

    Thank you in advance for your help.

  2. #2
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    I have never heard of any requirement to put fuses under lock and key.

    Can you cite an OSHA section requiring that?

  3. #3
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    Apr 2017
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    Piketon, Ohio, USA
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    I worked in the 13.8kV switchyard for years, and YES, fuses are an acceptable energy isolation device and YES, they can be used in LOTO. You do not lock them out, only tag them out. The tag has to be over the fuse block.

    I know I can use them in a LOTO program, my question was, in the scenario I laid out, do I NEED to control them. Like I said, I think I do, because I am controlling system status (and, because that would ensure I always done an isolation verification). If I don't control them under LOTO, my problem then becomes, HOW do I ensure that (1) an energized work boundary is put up around the exposed 480V heater connections; and/or (2) that they have verified zero voltage, therefore no boundary needed. It is not consistent here now, and I need it to be.

  4. #4
    Join Date
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    To protect employees from the unexpected startup or energization of parts, there are two options: LOTO or have the equipment rendered inoperative. Pulling the fuses renders the equipment inoperative. Here's an interpretation of the Construction Industry Standard, which covers "construction, renovation and repair, including painting and decorating."

    https://www.osha.gov/pls/oshaweb/owa...ONS&p_id=25516

    The rules for maintenance and operations are slightly different, but rendering something inoperative is always an option.

    BTW, locking up the fuses would be useless anyhow, since someone intent on starting the equipment could bring his/her own fuses.

  5. #5
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    Quote Originally Posted by wtucker View Post
    BTW, locking up the fuses would be useless anyhow, since someone intent on starting the equipment could bring his/her own fuses.
    I would never recommend locking up the fuses. The rule is to tag out the fuse block. I really do know how to apply LOTO to fuses, we done it all the time in the switchyard, that was the only way to do some of the work there without taking out an entire bay.

    I appreciate your attempt, and I think I can actually use the info in the link, cause I would even agree if we just hung OOS tags on the heater fuse blocks, as long as it was a process that would make them check for absence of voltage.

    What I don't want, is them to pull the fuses, leave them lay out there, leave the 480V lugs exposed, and walk away. Which is what I found. That way, there is NO control on the heater circuit what so ever. If someone were to walk by and reinstall the fuses, we would have exposed 480V in the back of the boiler.

    I am looking for something that tells me how to deal with a situation where I want to control the status of the equipment rather than protect personnel. I guess I could use the argument that tagging out the fuses protects personnel from the accidental exposure to 480V if the fuses were to get reinstalled...

    It has to be a process that even if I am gone, will be performed the same way each time. Not open for interpretation. Maybe I am not making myself clear...

  6. #6
    Join Date
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    You can always make more strict policy than OSHA.

    "What I don't want, is them to pull the fuses, leave them lay out there, leave the 480V lugs exposed, and walk away. Which is what I found. That way, there is NO control on the heater circuit what so ever. If someone were to walk by and reinstall the fuses, we would have exposed 480V in the back of the boiler."

    If you want to lock the fuses away, write it up as part of the policy, buy a $10 briefcase with tumbler locks, stencil the outside "FUSES" or something, and have the fuses under control of the electrician who is performing the LO/TO.

    Just curious, are there no breakers or disconnects that could be locked out in the off position, thus making it impossible to re-energize the equipment?
    Electricians do it until it Hertz!

  7. #7
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    Quote Originally Posted by JFletcher View Post
    You can always make more strict policy than OSHA.
    I had the same thought. And some customers have more stringent specifications than are required by mandatory standards.

    Quote Originally Posted by JFletcher View Post
    "What I don't want, is them to pull the fuses, leave them lay out there, leave the 480V lugs exposed, and walk away. Which is what I found. That way, there is NO control on the heater circuit what so ever. If someone were to walk by and reinstall the fuses, we would have exposed 480V in the back of the boiler."


    If you want to lock the fuses away, write it up as part of the policy, buy a $10 briefcase with tumbler locks, stencil the outside "FUSES" or something, and have the fuses under control of the electrician who is performing the LO/TO.
    Sounds like a reasonable idea. It wouldn't resolve the exposed 480V lugs problem you mentioned. Not something I've seen.

    Just curious, are there no breakers or disconnects that could be locked out in the off position, thus making it impossible to re-energize the equipment?
    There is the possibility that an upstream breaker might feed several circuits some of which need to be operational so removing fuses for the circuit under consideration might be the only alternative to killing everything the breaker feeds.
    Last edited by GoldDigger; 04-03-17 at 07:52 PM. Reason: Fixed QUOTE tag
    Si hoc legere scis nimium eruditionis habes.

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