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fuses blow

Discussion in 'Question of the Day' started by soundop, Mar 19, 2006.

  1. soundop

    soundop Active Member

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    ok so in the middle of the show the fuses for your ligh board and sound board blow, and the audience starts to panic what would you do?
     
  2. soundman

    soundman Well-Known Member

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    Let house manigment deal with the audence, if the situation would not be able to be fixed in under a minute throw some house lights on if possible. First question would be why both went at the same time. The best anser I can think of is a electrical surge hit the building. If it is storming out that might be an explanation but then why wasn't the surge stopped at the surge protector ? To go about fixing the problem just pull out the spare fuses that should be kept some where around the theater.
     
  3. soundop

    soundop Active Member

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    true, but surge projectors fail
     
  4. Footer

    Footer Senior Team Senior Team Premium Member

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    get to a safe place in the buidling because crap is hitting the fan
     
  5. Chris15

    Chris15 CBMod CB Mods Premium Member

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    My guess is that if you simultaneously blow both fuses, then that is going to be the least of your problems. For something to cause that, its going to be rather strong. Something that strong is probably going to knock out other things in the theatre. I say hit the emergency lights and see about replacing the fuses, but remembering that fuses blow for a reason and really you should find what caused the fuse to blow and fix that before replacing the fuse.
     
  6. soundop

    soundop Active Member

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    the reason i asked is because my middle school had wired the light and sound board to the same fuse and it blew
     
  7. AVGuyAndy

    AVGuyAndy Active Member

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    I really hope that there are no fuses, at all. It sounds like they are both on the same breaker on the panel. In that case, just flip the breaker on.

    In our auditorium, if the power goes out then the panic lights automatically go on.
     
  8. MircleWorker

    MircleWorker Member

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    Fuses in the Building? I hope you mean breaker. Initially I would throw our lights up through an architectural control unit. If it is the main power coming into the building, then we have a generator that takes over, for emergency lights only.
    I've had a show were everything went out, it was one of the craziest things ever to happened to me. The ushers and I had to use flashlights to get about 500 people out of the auditorium.
     
  9. CHScrew

    CHScrew Active Member

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    A few years ago, our light board and both of our spots went out during a show. Mainly because whoever wired our booth was STUPID. So, when we thought we wound be OK using an outlet on the opposite wall for the followspots, it turns out that the lightboard and both spots were all running of the same circut and it flipped the breaker in the middle of out performance of "Oliver". We just ran outside and turned on the emergency lights (the lightswitch to turn them on is in the middle of the auditorium), then went and fixed the breaker. Ever since then we haven't had that problem anymore.
     
    Last edited: Mar 20, 2006
  10. RelativeMischief

    RelativeMischief Member

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    Good idea to shut off the power amps for your speakers before flipping any breakers back on.
     
  11. Chris15

    Chris15 CBMod CB Mods Premium Member

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    Is not the answer simple? Know what circuits are where and what they are rated for and don't overload them. And if there are serious problems, get it rewired by an electrician.
     
  12. mbenonis

    mbenonis Wireless Guy Administrator Premium Member

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    In my opinion, if the lights remain out for more than a few seconds, then the stage manager (or designated crew member nearest the stage) should step out and ask the audience to please remain seated. In the mean time, the house crew should ensure that everyone is OK and assist any persons needing assistance.

    Every theater should have a written emergency situation plan that covers things like this, and all crew members should know what to do in various situations.
     
  13. ManOfLights

    ManOfLights Member

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    Just what ever you do dont replace it with a .22 bullet... there pretty much the same size.. i say this because i have heard stories that if the surge happens again the bullet will shoot... probably causing injury
     
  14. AVGuyAndy

    AVGuyAndy Active Member

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    This was tested on Mythbusters and they only got them to fire with heavy gauge wire shorted to the car battery. You won't find fuses like that on a panel.
     
  15. Mayhem

    Mayhem Senior Team Emeritus Premium Member

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    Well I have seen jewellers screwdrivers and also 16AWG solid core wire used before. I actually thought of buying the guy that used the screwdriver a cheap set of them and grinding a flat section and engraving 250mA, 500mA, 1A etc on the different sizes. However, I never actually got around to doing that. Besides, I probably would have gotten confused as to whether Philips drive screwdrivers are fast blow or not.

    As already pointed out, a fuse blows for a reason and whist it is possible that it failed due to a mechanical fault it is most likely that it did its job and protected your expensive equipment from major damage.

    A fuse should only be replaced with one of two things. Another fuse of the correct rating (remember, that someone may have placed a lower rated fuse in – and I have actually purchased equipment that has specified a 3.15A fuse only to have 2A fuse in it), or a breaker of the same rating.
     
  16. koncept

    koncept Active Member

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    i just read this, i though fuses/breakers only blow when too much current is drawn? can they be blown if too much is available/applied such as in a surge?

    second, if the equipment can operate correctly on a lower amp fuse wouldn't it be smarter to keep the lower fuse in there so that it blows sooner in that kind of event?
     
  17. soundman

    soundman Well-Known Member

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    I was talking about keeping a set of backups somewhere in the theater.
     
  18. Chris15

    Chris15 CBMod CB Mods Premium Member

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    A fuse blows when too much current passes through it. It is irrelevant whether or not this current is caused by a surge or whatever.

    The problem I see with a lower rated fuse is that it would be prone to premature tripping. This could mean that it trips mid show because you pull the full load and the fuse cannot handle it. Having said that though, if you must put a different value fuse in, a lower value would be safer.
     
  19. Mayhem

    Mayhem Senior Team Emeritus Premium Member

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    Chris is right – the fuse doesn’t care what current it has available to it, it only cares what passes across it. Think of the Chauvet Insignia light that was mentioned in another post. This particular light (I still had the pdf open!) has a 6.3A fast blow mains fuse in it.

    You can plug that light into a 20A outlet and the fuse doesn’t blow. The fuse will blow however if a fault occurs in the light that causes a power draw of greater than 6.3A.

    Say for example that the unit got wet and shorted the power supply – the current draw would rise dramatically, and the fuse would blow, protecting the unit from damage.

    Now surge protectors are an interesting topic and one that I am not going to go into in any depth – I’ll leave that for someone else to research. What I will say however, is that your fuse will generally not protect you. The hint that I will give you is that when we discuss electricity, we commonly discuss two variables.
    Consider these questions:

    1. What does a fuse/breaker protect against?
    2. What is a “surge” or “spike” in electricity?
    3. How does a surge protector work?

    Again – using a lower rated fuse could result in the fuse blowing whilst the equipment is working under normal conditions. However, using a lower rated fuse in a pinch may get you through a show (although there is no guarantee). However, do not put a larger rated fuse in as you really do risk further damage to your equipment and will certainly void your warranty.

    Whilst on the topic of fuses, I will also add in these questions:

    1. What are ceramic fuses and why are they used?
    2. If a ceramic fuse blows and you have no more ceramic fuses, but do have a standard fuse of the same rating, should you use the standard fuse?
     
  20. Chris15

    Chris15 CBMod CB Mods Premium Member

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    1] A fuse/ breaker engages when too much current is pulled through it. It protects against overloading.

    2] A Surge / spike occurs when the voltage is higher than normal, usually for only a very brief period of time. Now this spike is often in the order of a few thousand volts, quite a bit higher than standard mains voltages, no matter which part of the world. This voltage has a habit of zapping sensitive circuitry, which is why the use of a "surge protector" is useful. Interesting fact: it is a spike if the voltage increases lasts only one or two nanoseconds and a surge if the increase occurs for three or more nanoseconds. A power increase can cause wiring to heat up and melt or burn. That is not a good thing. I imagine that this would be more observable or heavily loaded cabling more than lightly laden wiring.

    If no one else offers insight into the workings of a surge protector and ceramic fuses, I'll do some research, but I'm sure someone out there knows more than me about it. The correct name for a "surge protector", a surge diverter, may offer some insight into its workings.
     

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