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Thread: Why do they both trip???

  1. #171
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    Quote Originally Posted by Ingenieur View Post
    http://www.talcofire.com/Glossary.html

    Booster/Jockey Pump:
    An auxiliary pump used to maintain system pressure without starting the main pump. These pumps are not designed to keep up with full system demand, their only function is system pressure maintenance


    Right booster pump, jockey pump, pressure maintenance pump likely other names as well but not 'fire alarm booster panel'.

  2. #172
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    Quote Originally Posted by iwire View Post
    Go back to bed.
    I'm not finished haunting this forum for the day yet
    What is esoteric knowledge today will be common knowledge tomorrow.

  3. #173
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    OK so I read most of this thread. We have the exact situation for one of our clients. The breaker will trip when going from generator back to utility. It will be a series coordinated fault, tripping breakers straight down the line (3) 225A breakers. There's a transformer at the end at 75kva. We adjusted the instantaneous setting and the problem went away. We felt the problem was due to asymmetrical fault inrush current because it would depend on where in the sine wave it was switched over. This site is also customer owned including transformers upstream.

  4. #174
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    Quote Originally Posted by 310 BLAZE IT View Post
    OK so I read most of this thread. We have the exact situation for one of our clients. The breaker will trip when going from generator back to utility. It will be a series coordinated fault, tripping breakers straight down the line (3) 225A breakers. There's a transformer at the end at 75kva. We adjusted the instantaneous setting and the problem went away. We felt the problem was due to asymmetrical fault inrush current because it would depend on where in the sine wave it was switched over. This site is also customer owned including transformers upstream.
    There is no fault, just a temporary spike in current when that transition is made.

  5. #175
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    VFD's wont start a motor already spinning unless they have "on the fly starting" abilities and is enabled, for similar reasons.

  6. #176
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    Quote Originally Posted by mbrooke View Post
    I'm not finished haunting this forum for the day yet

  7. #177
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    Quote Originally Posted by iwire View Post
    Right booster pump, jockey pump, pressure maintenance pump likely other names as well but not 'fire alarm booster panel'.
    booster pumps have a fire alarm control panel with pressure controls, starter, alarming, etc.
    hence 'fire alarm booster panel'
    I do not see 'fire alarm booster panel' on your pnl schedules, only 'fire alarm control panel' and 'fa power suply'

    regardless
    imo the breakers are set too low and are of the wrong type, no toc element (is that even code compliant for this application?)
    perhaps fire alarm, elevator and emergency ltg may be exempt if desired from oc protection? (only need sc)

    swap them out for I/t and your problems will disappear and you will have better protection (I think you can leave the main, just crank it up to 800%/1600 A)
    Last edited by Ingenieur; 03-20-17 at 11:43 AM.



  8. #178
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    Quote Originally Posted by Ingenieur View Post
    imo the breakers are set too low and are of the wrong type, no toc element
    Apparently you have not bothered to look up the actual breaker data sheets yourself.
    Magnetic trip only breakers are relatively rare. Magnetic only mounted into standard panelboard construction are extremely rare, and may no longer even exist.
    Just because you can, doesn't mean you should.

  9. #179
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    Quote Originally Posted by Ingenieur View Post
    booster pumps have a fire alarm control panel with pressure controls, starter, alarming, etc.
    hence 'fire alarm booster panel'
    I do not see 'fire alarm booster panel' on your pnl schedules, only 'fire alarm control panel' and 'fa power suply'

    regardless
    imo the breakers are set too low and are of the wrong type, no toc element (is that even code compliant for this application?)
    perhaps fire alarm, elevator and emergency ltg may be exempt if desired from oc protection? (only need sc)

    swap them out for I/t and your problems will disappear and you will have better protection (I think you can leave the main, just crank it up to 800%/1600 A)
    If you use that term in conversation with anyone who is familiar with both fire alarm and sprinkler, I'm betting 99 out of a hundred will assume you mean a notification appliance booster power supply. especially since it says "alarm", and the hundredth will ask you to repeat the question.

  10. #180
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    We call them "NAC panels" here.

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