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Camlocks

Discussion in 'Question of the Day' started by koncept, Oct 1, 2005.

  1. koncept

    koncept Active Member

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    I am now working at my college theatre and they loaned out thier portable dimmer pack and camlock extension cord. I am wondering according to the nec what is the correct ends per phase (3p+n+e). Also what is the correct way to rewire the camlock ends when the pack was returned the ends that go to our wall point had all been hacked off and shoved into a disconect with a screwdriver (so im told)

    thanks in advance
     
  2. inspector_gizmo

    inspector_gizmo Member

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    Koncept, I am no expert when it comes to power distros and three phase, so please wait till somebody more experienced comes along to make sure what I am saying is correct but from what I read I'll try to help you out.

    PLEASE NOTE THAT THIS INFORMATION IS ONLY FOR YOUR CONVENIENCE, IF YOU ARE UNSURE ABOUT ANYTHING THAT YOU ARE DOING PLEASE HIRE A QUALIFIED ELECTRICIAN, THREE PHASE CAN KILL, AND WILL IF YOU ARE NOT CAREFUL.

    1) You want to know which cables connect to what?

    In a three phase system, green is ground, white is neutral, and red, blue, and black are your three phases of power, when connecting always connect from left to right, or ground, neutral, ph1, ph2, ph3.

    2) From what you have said it sounds like when they borrowed your dimmers, you gave them your 3-phase feeder cable "extension cord" as well which had camlocks on both ends to connect your dimmers to a camlock outlet somewhere in your theatre, but when they returned it, they cut the camlocks off of one of the ends to connect them to a bull switch?

    This is not only rude, but also illegal if your feeder "extenstion cord" was longer than 10 feet.

    Please do not try to put the camlocks back on yourself, it is a very tedious process and it requres special tools in order to do them right. You may end up having to buy a new set of feeder or get someone to put new camlocks on depending on which is more costly. I would see if I could get the show that borrowed your feeder to reimburse you for the repairs on your cable because camlocks are not cheap to buy, though this is only the ideal situation. It's likely they will try to pass the buck especially considering their electrical practices that you have noted, and you will never see a dollar in reimbursement.

    Forgive me if I do not give you more credit, but since I do not know your electrical background, I am erring on the side of caution. Hope my advice helps, and I'm sure others can chime in more for I only have the knowlege of a 16 year-old who has read as much as he can on the subject of power distribution.
     
  3. koncept

    koncept Active Member

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    ahh yes, another young kid like my self. i am currently 18, I have done my fair share of electrical but never with cam locks

    problem is we cannot get ahold of the person who borrowed the pack. the "extension cord" is closer to 50 feet i think.

    1. the cables as to what connect to what, on the wall disconect, we have the 3 legs with female ends and the neutral & ground with male ends. on the dimmer pack they are all male ends. so seeing that it seems as though our feeder cable performs something more than just providing power. that why im asking about male/female cams per leg.

    2. you are correct. do you know where i could buy the tool and new cam ends?
     
  4. inspector_gizmo

    inspector_gizmo Member

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    I'll just say that the show that borrowed your dimmers is lucky they didn't have an electrical inspector, and that they are even luckier that they didn't have anybody or any equipment injured. Bad electrical practice is a real pet peeve of mine, and now that I've learned more, it scares me even more to hear stories like yours.

    Your male vs. female outlet dilemma is a common issue, there is nothing special going on with your feeder besides the fact that it has different ends on the ground and neutral. You need something called a suicide adaptor for your ground and neutral, yes they call it that because it can be very deadly if used improperly. It just basically is a like-sex to like-sex adaptor, It sounds like they forwent the suicided adaptor and put different ends on your feeder, probably the best idea in an educational environment.

    The only place that I know of off the top of my head for camlocks is J-Custom Supply at http://www.camlok.com but I seriously warn against putting on your own ends. They might also have the tool, but in the end it may just be cheaper to have them do it for you.

    Hope this helps.
     
  5. jonhirsh

    jonhirsh Active Member

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    Hey the all male ends is a Film standard, what you can do is call your local rental house and ask for a film to rock cam jumper they whould know what you mean that will get you back to the rock style of cam tails.


    to be honest if you dont rewire cam tails all the time the cost of the tools is huge. your better off just buying a new jumper.


    now as for is it illegal to run an cam extension no its not but you lose power with every foot of run for some shows we run 100's of feet of extension. so i am not quite sure as to what your calling illegal about running cam extensions.


    wish i could be of more help to you
    JH
     
  6. inspector_gizmo

    inspector_gizmo Member

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    Jonathan, I know it is not illegal to run cam extensions, but am I wrong in saying that you can not run 50 feet of cam cable directly to a bull switch or directly to a circuit breaker if using bare tails to cams?

    I thought that code said you must have bare tales to cams witin 10 feet of the disconnect or breaker and then from there you can run your 50 foot or more extension. If you have cam connectors directly mounted on the wall thats a different story.

    However the company that came in and cut off the ends was doing something illegal by cutting off the cams at the end of the 50 feet and then connecting them because it poses a serious hazard. If the cams were connected to the extension at 10 feet as code specifies, then it would be less likely for something to get disconnected and possibly injuring someone or at least destroying a piece of equipment.

    If I'm interpreting the code wrong, please correct me, but the 10 foot rule does make a lot of sense. Hope all of this can be cleared up.
     
  7. koncept

    koncept Active Member

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    thanks for the info Jjonhirsh, let me give a cable diagram.

    this is the cam "extension cable"
    dimmers - disconect
    f red - m red
    f black - m black
    f blue - m blue
    f white - f white
    f green - f green

    i am asking if that is normal or if that is something different. if it is, while we are re-doing the cable should anything else be changed.
     
  8. jonhirsh

    jonhirsh Active Member

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    um as far as i know from experiance that set up is used for film. if you paln on useing it in a theatre you will need to change the orientation of the sexes.


    i think you might be right about the cam tails being under 10 feet but to be honest i can not think of any reason why this would be true. to me it dosesnt seem safer or less safe to me either way.

    JH
     
  9. ship

    ship Senior Team Emeritus Premium Member

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    Inspector Gizmo is absolutely correct in all he has said so far including the 10' rule. Not so sure about inspectors knowing the code that well but point is to do a professional job and not worry about if or if not it's imspected.

    It's somewhat unfortunate but common that people do things to get a show up and running safe and good practice or not the show must go on.

    Did they give you back your plugs? Dependant upon the brand or skill level of those that can install them, it might be easy and cheap enough just to re-install the old plugs if in good condition back on your cable. At that point you would only be charged labor. This given it's not volcunized / injection molded plugs or old style CamLoc that most of the time while you can extract the pin, doing so unless just right will destroy the plug or it's insert pin.

    Many newer brands and of Cam type connectors out there, your electrical supply house can also provide them and the adaptors should you find a tech person to come out and install them for you. Suicide adaptor is a new one on me but I understand where the term might come from.

    Advanced Devices/mancuro, Leviton, Hubbell, Pass & Seymore amongst many brands make this type of plug and it's a universal fit between brands.

    Theater supply, rental company, movie house etc, most will probably have at least one person on staff that's trained in installing them. I just spent the last couple days making dozens of them for productions. Not my favorite cable to build but easy enough once you start going. Your supplier can probably send someone out to install them but it might be better to bring them in so as to save on on-site charges. Make sure you tell them what gauge of wire your jumper is using because there is two sizes to the plug in matching a variety of sizes of cable. #2-2/0 and 2/0-4/0.

    It's not really that hard to install and dependant upon the brand, does not require too many other than standard tools. Might be able to get instruction on it. The torque wrench is probably the most expensive part. Some people don't use them, don't trust such people to work on your plugs. There is a very specific torque that must be applied on something that can carry up to 400A of current. Most plugs no longer require the pin insertion press - though they can get stuck and using it makes life much easier. Main custom thing you would need is a set of male and female locking wrenches that cost about as much as a new plug.

    While having the cable fixed, have them make and sell you a set of "tails". This would be a 10' jumper with a bare end which could go into a set of lugs in a generator or power distro, which than your jumper cable would plug into. Had this already been available, your jumper will not have been cut.

    Double female neutral and grounds.... never seen that before. My guess would be that the theater is wired as per the reverse neutral and ground technique that prevents the wrong color of conductor from plugging into the wrong terminal, and the dimmer pack is using the other standard of all the same sex.

    Does it need to be changed? It would be nice to have a unified system and at least than you would have a 50% chance of being right in using your gear with other people's. On the other hand, done is good, just keep some MM adaptors around for which ever end of neutral/ground is incorrect. that's not a bad thing though due to torque issues it might be better to have them as a cord mounted turn around than barrel mounted one.

    The extra length of the turn around when added to the weight and length of the plug can damage the panel mounted outlet at times. Instead a short say 18" male male jumper would ensure the added length is not a problem. Not an idea used much but a good one.
     
  10. koncept

    koncept Active Member

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    We recieved 4 of the plugs back. Would it be easier to just buy new ones? Is there a guide on how to install cam locks? In the process of repairing the cable, we found that 2 of the cams had copper rolled round the stranded #2 conductors, is this supposed to be there?

    Our master electrician at the college has never worked with cams before, so in making some calls, they were told that if the cams were not prefect (no nicks, scratches, ect) they would not work correctly, is this true?

    Thanks for everyones help
     
  11. ship

    ship Senior Team Emeritus Premium Member

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    There is full instructions with every new connector but it's recommended for the details and tricks on how to, have someone say teach the ME how to do it.
    For instance once in a while where I work I'll do something like this or install some Socapex plugs at the same time I'm teaching the customer how to do it. As long as the sales person feels the customer would be able to safely do the task they at times like this will just charge labor and parts while I teach. Depends upon how much help in being a full service supplier verses "this is what you pay us for" type of phylosophy those suppliers near you have in mind in getting instruction on something like this. To the supplier's defense there can also be a liability issue with instructing how to do such things. I certainly again would not teach just anyone how to do this.

    Your college ME should be able to get instruction on such a thing and buy the one more you need given the others are in good condition.


    "told that if the cams were not prefect (no nicks, scratches, ect) they would not work correctly, is this true?"

    Hmm,

    Hmm,

    I could see them saying that unless the plugs were in good condition they would not install them, I would not either, but scratches, etc. preventing them from working properly...., that's a new one. These plugs are fairly hard to scratch.

    The main thing you want to watch for is the rubber boot over the brass pin. Especially on the neutral it will frequently start to wear away at it's edge. Otherwise if overloaded there will be a browning of it where the rubber boot is thinest. Another thing that might prevent me from re-using the plug could be corrosion especially on the set screws, or excessive wear near the locking pin or lock for the rubber outer covering. Also I like a fairly tight fit at the point the outer jacket of the cable goes into the plug. While not water proof, it's a slight bit more moisture resistant when fairly tight here.

    I also would demand the proper plug goes on the proper cable. I don't accept electrical tape over plugs of the wrong color.

    All this and very dependant upon the brand of plug I might not install it because I could not ensure that in removing it from the old cable something that holds the rubber cover to the pin would not break. I have very bad luck with one or two brands and easily remove and swap out others.
     
  12. koncept

    koncept Active Member

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    Thank you for the information. I will pass this along when I go in today.

    there were a couple of scratches, but I think they were from when the guy who hacked the ends off tried to put them back on, my guess is he was using a pair of vice grips and had it a bit too tight.
     

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