The above Ad will no longer appear after you Sign Up for Free!

Brand new scoops

Discussion in 'Safety' started by renegadeblack, Nov 7, 2008.

  1. renegadeblack

    renegadeblack Active Member

    Messages:
    433
    Likes Received:
    7
    Location:
    New Haven Area, CT
    So I was for the first time setting up some scoops that were sitting in the band teacher's room that had never been set up. Unfortunately, they all have edison plugs on them so I have to make a bunch of adapters to take care of that, but I first plugged them in to the wall to make sure that they worked. I went ahead and put an adapter in and hung one of the lights. I go back to the board to turn up the channel and I see sparks flying from the light. Needless to say, I turn it off and run to the stage with the fire extinguisher. No fire fortunately, but I marked everything fire hazard(everything but the light was in question). I'm fairly certain that it was the edison converter, but for now, I went to mark the dimmer and found that the breaker was tripped. Anyone know what could have been the culprit? We're talking like sparks that looked like someone was up there welding.
     
  2. Sony

    Sony Active Member

    Messages:
    856
    Likes Received:
    96
    Occupation:
    Freelance Electrician/Rigger
    Location:
    Massachusetts
    Most likely it was just a dead short in one of the connectors or from a connector to a pipe or something metal it was touching. The best course of action would be to go and leave the breaker off, and check all the connectors and adapters. Look for signs of arcing like melting or charring, parts with a black coating of corrosion is a big thing to look out for. If you find signs of arcing then I would take apart the plug/plugs with the signs of arcing. If I couldn't find any signs then I would personally take apart every single connector until I found the problem.

    WARNING: DO NOT TAKE APART ANY CONNECTORS IF YOU DON'T KNOW WHAT YOU ARE DOING. ELECTRICITY IS DANGEROUS AND CAN KILL YOU IF YOU DON'T KNOW WHAT YOU ARE DOING. WHEN IN DOUBT, CONSULT A QUALIFIED ELECTRICIAN!!!
     
    Goph704 and (deleted member) like this.
  3. Footer

    Footer Senior Team Senior Team Premium Member

    Messages:
    9,392
    Likes Received:
    1,789
    Location:
    Saratoga Springs, NY
    First, I assume when you plugged them directly into the wall they turned on and and everything was happy?

    Here is what you need to do.... walk away, find someone that can inspect all your cabling/adapters/fixtures to make sure everything is properly terminated. I have a feeling you have some very poorly made cable, and you need to get someone in there that can fix it. Odds are it was a dead short in the adapter, you need to get everything checked. If there is one bad cable or adapter, there is more, guaranteed.
     
  4. Sony

    Sony Active Member

    Messages:
    856
    Likes Received:
    96
    Occupation:
    Freelance Electrician/Rigger
    Location:
    Massachusetts
    I definitely agree with Charc, just be nice and you will be amazed how much people will be willing to help you. This year at MVPAC I got the school maintenance department to give me 32 brand new T8 Tubes to change out our worklights. ALL of the tubes they had left and they just gave them to me out of their budget. I also got them to help me change the house lights which are 40 feet in the air and not lowerable to the ground, they are also over the stadium section so we had to do it with a 40ft tall extension ladder, we couldn't use the genie lift. It was some scary crap...but they helped me out in their free time and it was cool.
     
  5. elite1trek

    elite1trek Active Member

    Messages:
    133
    Likes Received:
    0
    Location:
    Baltimore MD
    I agree too, however...

    Alot of maintanance people, especially at schools, are like network administrators. They don't like lots of hands on things that are in their building, whether it is actually their domain (networking pun not intended) or not.

    So, ask your maintance guy (or girl) if they wouldnt mind helping you fix something, but if they don't respond in a cheery, happy, sunshine-filled face, dont be surprised. If they do respond poorly, take it up with your teacher/advisor to take it up with them.

    Hopefully that (^) won't be the case, I know when I was in college the Plant Operations guys were awesome, always sparing a box of florescent tubes or spools of wire should we need it.
     
  6. renegadeblack

    renegadeblack Active Member

    Messages:
    433
    Likes Received:
    7
    Location:
    New Haven Area, CT
    Yes, after I plugged it into the wall again, everything was happy and such.

    I marked everything that was involved and unfortunately, we don't have any sort of district electrician at my school. The people who do the electrical work are contracted and after getting a new advisor who actually does stuff, we've found that our budget line was eliminated so no contracting for us. When stuff that isn't contracted, it's done by the day janitors who seem to really not like us, the night janitors however just gave me a bottle of wd-40 when I only asked if I could borrow it last night :p . So the person who does the electrical work is me under the supervision and blessing of our tech advisor who teaches the power and electronics courses at our school.

    As for when you mentioned that they all need to be checked and fixed, when I was told to take apart one of our adapters to see what gauge the wires were and found that there wasn't a negative terminal wired leaving only positive and ground.

    As for what Sony said, I'm not using the channel and when I went back to the dimmer rack, I went back there intending to flip it to the off position and found that it was already flipped. I am in no hurry to flip it back on :) I was also looking for signs of where the fault was and have yet to find it. I've only eliminated the scoop from being part of the mix. I haven't seen any signs of where the fault actually was.

    I am comfortable with wiring a new adapter on the ends of the scoops and I have succesfully. Right now we intend to put 3 prong adapters (what are they officially called?) onto the lights and be done with it.
     
  7. derekleffew

    derekleffew Resident Curmudgeon Senior Team Premium Member

    Messages:
    4,366
    Likes Received:
    2,741
    Location:
    Las Vegas, NV, USA
    Male Stage Pin Connectors.
     
  8. waynehoskins

    waynehoskins Active Member

    Messages:
    782
    Likes Received:
    49
    Location:
    Arlington, TX
    An experiment to try (which will either work properly or give the result you experienced earlier):

    Hang the fixture on a pipe and plug it into a wall outlet with an Edison cable.

    If it throws sparks, that means your fixture is miswired.

    But this adapter you speak of .. with AC there is no Positive or Negative (that's DC), only Hot, Neutral, and Safety Ground. Open the adapter up and look to see that it's wired properly:

    For a 20A-2P&G Stage Pin Connector:
    Hot = Black wire = 2PG pin farthest away from center pin = shorter Edison blade = brass (gold) colored

    Neutral = White wire = 2PG pin nearer center = larger Edison blade = silver colored

    Safety Ground = Green wire = 2PG center pin = Edison round pin = U-shaped, green screw
     
    Last edited by a moderator: Nov 8, 2008
  9. renegadeblack

    renegadeblack Active Member

    Messages:
    433
    Likes Received:
    7
    Location:
    New Haven Area, CT
    I have already plugged the fixture back into the wall and set it on a wooden bench and it worked fine. I'm assuming that you say to put it on a pipe so that if it's mis-wired I wouldn't get a hell of a shock. I will be headed to the school in about an hour so I will take a look at the adapter and see if it's wired like you say it should be. I did look at another adapter to see the gauge and found that it was dangerously miswired.
     
  10. photoatdv

    photoatdv Active Member

    Messages:
    934
    Likes Received:
    32
    I think he said the pipe to rule out that it was shorting onto the pipe. That doesn't seem very likely to me though.
     
  11. leistico

    leistico Member

    Messages:
    56
    Likes Received:
    3
    Location:
    KS
    Here's how you test these things without plugging them in or throwing sparks anywhere.

    Invest in a multimeter. Preferably one (of the greatest possible cheapness, available at any hardware store) that measures up to 600v AC, plus has an ohms setting -- my own has a "beep" tone at very low resistances that I can use to check continuity.

    Use that multimeter to check continuity on the instruments and on the adapters (unplugged, of course). You should get continuity on one and only one wire at a time. On the instrument, your ground connection should get continuity on the frame of the instrument, your hot on one pin/side/end of the lamp connector, and your common on the other, with no other signs of continuity. All that is with the lamp removed. With the lamp in place, you should get continuity from hot to common, from ground to frame of the instrument, and *never* between ground and either hot or common.

    Also (something I found in my community theatre a few times, following less-experienced guest LD's), give the wires a tug. If a wire pulls out of the connector or instrument, there's a really good chance that that's your problem
     
  12. 1kfresnel

    1kfresnel Member

    Messages:
    41
    Likes Received:
    4
    Location:
    Buffalo, NY
    I agree with leistico, a multimeter, or at minimum, a continuity tester is a must have. Also, if these instruments are being prepared to stay in your space for awhile, skip the adapters and wire the proper plug directly on to the tail. One less point of failure is always good!
     
  13. dramatech

    dramatech Well-Known Member

    Messages:
    466
    Likes Received:
    111
    Occupation:
    MASTER ELECTRICIAN
    Location:
    Winter Haven, FL
    Many years ago an associate at work asked me to help solve a problem of a scoop used in a photo studio sparking and throwing breakers. The curious thing is that it worked on one outlet, but not on another. The problem was two fold. First the neutral wire (white/large silver pin on edison) had been pinched when the scoop was assembled. Secondly one of the outlets had been wired with the hot and neutral reversed. Because neutral and ground are frequently connected together at the breaker switch panel, There was no problem when connected to a properly wired outlet, with the pinched neutral shorting to the ground in the scoop. When plugged into the incorrectly wired outlet, the pinched neutral became shorted to the hot.
    What Waynehoskins is suggesting is something very similar. When the scoop mentioned is sitting on a wooden bench The frame of the instrument may be hot but is not grounding. When attached to a pipe, The hot is grounding to the building ground.
    Two possible problems, first the neutral is attached to ground in the scoop and the hot/neutral wires are reversed in the connector. Second the connector is wired correctly and the hot wire is touching the frame of the instrument. My best guess is that the hot wire is touching the frame, and not to tightly, which would account for the sparks as the wire moves about when receiving current. If it was a solid short or miswired, there would be a greated chance of it throwing the breaker without sparking. The advice to use an ohmmeter or continuity tester to determine if the hot wire is shorted or the connector is miswired allows a novice to learn without all of the fireworks and possible injury.
     
  14. renegadeblack

    renegadeblack Active Member

    Messages:
    433
    Likes Received:
    7
    Location:
    New Haven Area, CT
    I've since changed them to stage pin with some spare adapters that I had lying around. I also tried plugging something else into the adapter and it didn't work. I also haven't used the same channel since the incident. I still have everything tagged out and unused but I'm fairly certain that it was the adapter but I'm still not taking any chances.
     

Share This Page