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Power distribution howto

Discussion in 'Lighting and Electrics' started by theLD, Jun 30, 2003.

  1. theLD

    theLD Member

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    I am currently searching for a good power distribution howto on the web. I need some good information on how to properly tie in power to dimmer racks(methods, etc.). We generally tie in a lot of power to run shows, and need a good way to explain what we are doing so our new guys don't screw something up. We generally only have a supervisor do the actual tie in, but in an effort to train we need to find some good info. If anyone knows of where I could go to get this info, please let me know.
     
  2. doc1

    doc1 Member

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    How are you tieing into your power and what type of power 3 phase, or delta, single phase.
     
  3. theLD

    theLD Member

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    Most of our power tie in is three phase, but occasionally we reach a venue that requires us to use only one phase. So info on either is fully welcome. As for how, we also tie in multiple different ways depending on where. I'm basically looking for any info we can find.
     
  4. doc1

    doc1 Member

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    Ok I can help.
    In power distrubution you have cables called feder cable this comes off your 3 phase panel or generator depends one where you are getting power from. Thes cables are usully thick and are a heavy gauge wire that is well insulated. Usully around a #2 wire for mediam tie in's but can get up to a 2ot (BIG CABLE). When tieing into you source it is smart to turn off the power, before opening the panel. In some caese this can not be done because of what is also connected to the disconect. In these rare cases you MUST have a person to be on a whatch just in case something goes bad.(TO PULL DISCONECT) In the case of your productions i dont think you have this problem. There is two ways you would tie into the power after the disconcect is OFF (And there is no power running throght the wires on the load side of the disconect.(CHECK WITH A MEATER) you would get a set of tails. A tail is a set of cables 3-4 feet long that have bare wire on one end and cam lock connectos on the other. This is a profesinal way of doing it. Or you could just tie in the dimmers directly into the panel. When connecting the tails or the power wires off the dimmers it is a good ideas to connect the gorund and then neurtral first then the phases. The reason why i do this is to remember that when connecting ANYTHING ground and neutral first. It dosent mater when the disconect is off. But when it is on if you connect a phase wire first and no neurtral or ground is connected, and a phases is going to ground or chasie of your equipment and you tourch the chasie you counld BECOME THE NEW CONDUCTOR TO GROUND (can any body say extra crispy). After you connect your power wire to your source of power you grab a multimeater and check your work. Turn on the power but before you turn on make sure there is not water around or you have no sorce of gorund. When you are dealing with disconects that have high potental. be verry carfull and smart. Once your are completly satisified that everyting is ok you will turn on the power and check with a meter form neurtral to al 3 phases and ground to the phases you should get around 115-125 depending on quality of meter and actual voltage. It you do not get this turn off power and check connections. Then re-check. If that dosent solve the problem call a certified electrican to chekc the panel for problems. If your are connecting to a generator there will be a adjustment knob for the amount of voltage just turn it up or down depending on the voltage if all 3 phase are to low or high. When your are getting good voltage turn off power and run all the extra cables if you are using tails. If your are direct connectiong the dimmers you are good to go. Once all the feder cable is out you check the voltage one more time to see if any problems show up. If usiing a generator you want to up the voltage to account for line loss. Once that is all good connect the equipment. When connectiong the equipment you allways connect the ground and neutral first. Then turn back on your power and your dimmers are up.

    In some cases you migh hook up a distrubution unit whitch is a box with 3 phase power in and out you connect off the panel into the unite and the output goes to the dimmers. Follow all the same instructions when tieing in this equipment. A distrubution panels is a a panel that give you difftent types of outputs. for general power including single phase edison and 3 phase 5 wire and single phase 220. Thes boxes ties into the 3 phases in many difftent combinations to give you all the difftrent mediams used for difftent devices. Distrubutions boxes are uslully used for larger venues that use lots of inteligent lighting or do big sound gigs that require lots of power for power amps.

    If you have any more questions fell free to ask.
     
  5. wolf825

    wolf825 Senior Team Emeritus Premium Member

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    Oh my...where to begin...many many questions to address...

    Are you in the UK or in the states (power & phase panels are different accross the pond :) )? whats your rig--this to direct feed dimmers, or tieing in an installed panel in a building or is it to a disconnect or distro panel and breakout box that feeds more then lights? Also--you tieing in with bare-wire tail-sets, cam-locks, tweeko's, MASS, trico's (yep they are still around for those who know what they are) ? You use feeder cable--what guage and how many amps do you need for your rig? How do you load balance your rig if it can be for single or 3 phase? Is it switched internally or do you (yikes) jump phase? Do you use code-tape on your tails as well, or just go by the cam-lock colors--and what if your crew person is colorblind?? Are your cams reversed-sex on ground and neutral or straight? If they are not reversed--and you have newbies connecting, you may want to turn them around just to eliminate potential mis-connections. If you can post more info--less generalized, you can get a more direct answer.

    There are many factors & proceedures about tieing in...it IS somewhat simple but it also IS dangerous and must be done with extreme care and konwledge about what you are doing PLUS what you are tieing in to power. I will gladly post proceedures..but it won't do any good to tell you one way for a disconnect service and you are tieing into a generator or a sub panel, or if you have to add your own lugs or breaker in a breaker panel. Also if you have no ground or a ground rod or have to find one--there are a lot of factors when it comes to high voltage. Putting in the cables is just the first part--you have to meter and check voltages and for null-power as well, and ensure that all the way down the line things are correctly connected before you toss the switch. You also need to check the panel itself and make sure it is correct--I've come accross quite a few panels that use a chassis ground and not a return line..and some have a taped leg in a single phase panel...what do you tell folks to do then? When I lead my crews, if I am teaching how to do tie-ins, I teach thoroughly and my trainee for those few months will WATCH me quite a few times before I even will let them near the panels.. I will have them tell me the next proceedure until they know it inside and out--from connections to metering--what is an isn't acceptable, including what to look for and what should raise the caution flags. Mistakes, casual attitudes and slips of the tools can be deadly...you have to be precise and focused to do it right and not endanger yourself or someone else.

    Also, since this board is geared a lot to high school students & beginners who read this, let me be clear that NO ONE should EVER open or even TRY to do a tie-in if they don't know what they are doing. EVER. Especially if they cannot tell if a panel is single or 3 phase, WYE or delta phase, breaker panel or disconnect service, 120/208 or 220/440 or higher--and how you tell using a multimeter should it not be labeled, or how many amps are running thru it or the right wire guage needed, or how to detect a floating ground, or if the neutral and ground are bonded, and how to balance your loads on the legs, and not overload them, if that is a concern etc etc. There are certain safety proceedures that must be followed...and knowledge about this is imperative. The idea that someone tie into a LIVE panel and not know what they are doing is beyond stupid... I have tied into live panels on a very few rare occasions but I've also been doing production work for 15+ years and I KNOW what I am doing...and I know what I will and won't do too. And honestly--live panel tie ins are just plain STUPID today...

    As for links on live power tie-ins, there are a lot of detailed archived discussions on this subject in a few live production boards you could check out.
    Like www.live-audio.com and do a search in the LAB archives....

    Also I will glady answer questions and give proceedures...

    -wolf
     
  6. theLD

    theLD Member

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    First off thanks for the input wolf and doc. To answer a few quick questions, we are in the United States. We generally tie in our Sensor(96, 48 , 24) dimmer racks (they use camlock to tie in). However, due to the nature of our job, we travel to many different venues across the country and encounter different power tie in needs (tweeko, bare-wire, etc).(( I personally haven't encountered trico's though)) My main problem is not necessarily learning howto tie in power, but more finding an official site that explains some of the different aspects of the process. As you know, what we are talking about is serious stuff. We only allow our experienced and trained electricians do the actual tie in, but it would be nice to find some official documentation that we can begin to train some of our other crew members.

    And as wolf stated, anyone reading this post that isn't trained, experiementation is not the way to learn. Find someone that knows what they are doing!!!
     
  7. wolf825

    wolf825 Senior Team Emeritus Premium Member

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    Hiya,
    Glad to offer some advice--you're very welcome. You may wish to check out the LAB link I posted (there is a "PD for Dummies" titled post in the recent archives that is worth reading--just type in that topic in the search engine there and it should come up).
    You may also wish to check out some of the training seminars that are offered by some of the major electrical panel manufacturers like Cutler Hammer and Siemans. No better way to learn about connections & identification, and how things go together, then from those who build the panels you will tie into. Also, if you check out the web site www.howstuffworks.com they give plain language & drawing explanations of how power grids and distribution networks work. Could be useful for your needs. I've yet to come accross any specific website of info on power tie-ins, probably because there are so many variances in what persons may run into and what a specific person may be tieing into and for what reasons--and I'm sure the liabilities of posting "gospel" info in such a wide-range topic also hold many folks back. I know OSHA has some reference books, as well as the electricians code books are also most useful in understanding load balances and safety concerns.

    If you would like more information and some instruction on proper connection techniques, testing and identification techniqies of power panels, let me know and I will endeavor to post some instructional info on the subject.

    Good luck...
    -wolf
     
  8. wolf825

    wolf825 Senior Team Emeritus Premium Member

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  9. ship

    ship Senior Team Emeritus Premium Member

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    Wolf825, I'm glad you hopped onto the subject. I would have posted a similar warning. I also know what Tweeko's are. I have some mounted to my wall of shame and antiques. The rest are just different or smaller. The 60amp ones are now against code to use. I also by chance am going to be building one set of 4/0 and two sets of 2/0 tails in the morning. I like the Leviton ECT series of Camloc however. Good ideas on the source for using them. I remember 120 inch pounds for torque or was that foot pounds. The instructions on a CamLoc connector is another good source for instructions in building the cable.

    Doc1, You seemingly have done this before, there are a lot of people that know how to do this, but in this case, you might be better off contacting the person directly when giving the how to of this specific subject, especially if it's not right out of a book and surrounded with a lot of warnings such as Wolf825 did. Just too tempting for anyone to try it I would have to agree.


    By the way 2ot is written as 2/0 and it must be of type SC or W by code. It's only rated for 280 amps which makes 4/0 a more common feeder cable to tie in with for loads such as on a 96way dimmer rack and other equipment over 280 amps. (400amps.) Lots of more little details that would have I'm sure been corrected with more editing like the idea of doing a tie in to portable equipment without connectors. Bad practice. Something that could close you down. Plus many generators will be at a higher voltage until they are loaded than it will drop down in additon to voltage drop which you can only measure at the equipment. Metering amperage of each leg under load and overall in addition to metering voltage at the dimmer is also a good thing to note after you have done the paperwork of balancing your load and distribuiting it....
    But with more editing I'm sure you would have corrected it all yourself.
     
  10. wolf825

    wolf825 Senior Team Emeritus Premium Member

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    Hi Ship,

    I like the ECT connectors too...much better design and connections in them, and I find the boots for them seem to mold to the cable better--better for sealing & making them waterproof. Original camlok connectors I always use to feel better if I filled the boot end with some silicon or hot-glue to help the seal around the area where the cable entered the boot to not have any "leak" where water or debris could get in.

    -wolf
     
  11. ship

    ship Senior Team Emeritus Premium Member

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    I have a strong dislike for Cam Loc connectors. The little pins retaining them are always falling out if not the boot breaking at the pin. For a while I was re-using them and that just made the problems worse.

    There is a lot of styles out there including some like the Hubbell that you shove a fiberglass pin thru the boot, but I never liked that style because it seemed that if it could go in that easy, it would also fall out.

    Now I just need to get my Cam Loc press to better fit and not chew up ECT connectors. #2-2/0 connectors are especially rough to get done properly. Seems the set screw that's the same for a 4/0 one doesn't like to countersink as it would for the larger size when torqued to the proper amount on 2/0. Pain in the rear because all it takes is a bit hanging over and the boot won't fit even with the press. Than in installing and over-torquing there are the screws that strip. Last week I had to grab the grinder on some set screws just to make them work as they would not go in further and would never come out again.

    ECTs are tricky in the nylon set screw also. Had a lot of them break when installed just slightly out of alignment. Pain in the rear to remove than. Interesting that they are labeled for type W cable still. I don't know of anyone using it over SC anymore - thus cutting the boot one size smaller can be a problem if proper instruction isn't given.

    So I'm still open for another solution.


    Silicone is a good idea. I never much worried that myself. I don't think this connection is supposed to be more than water resistant. Probably not necessary for my application as nobody has brought it up with any (old/new) style of connector. Vulconized ones seal really well and last forever. If they were not such a pain to do, I would go back to them. Rhumer is that we still have the machine somewhere. During the last Sting NYC out door concert, they had a slight problem with rain. I'm fairly certain they got the feeder off the ground and wrapped them up well. Only things that came back worse for the wear asside from mud everywhere was a few Veam Soco connectors that provided their own light show and welded together - another part of my wall of shame - one of the ones that I was able to persuade apart.

    I can see the moisture seep however, but with either style. I think rusted set screws would be common to all given the same age. The person that tought me had the idea of using 16ga steel tie wire to retain the jacket. Ever since, when ever I open up one of those plugs to replace a boot I see a broken and very rusted tie wire.

    What do you "slide" the boot with? I usually use alcohol, but occasionally get lazy with the WD-40 myself.

    On the whole, doing feeder for a day isn't on my top ten fun things to do.
     
  12. ship

    ship Senior Team Emeritus Premium Member

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    I have a strong dislike for Cam Loc connectors. The little pins retaining them are always falling out if not the boot breaking at the pin. For a while I was re-using them and that just made the problems worse.

    There is a lot of styles out there including some like the Hubbell that you shove a fiberglass pin thru the boot, but I never liked that style because it seemed that if it could go in that easy, it would also fall out.

    Now I just need to get my Cam Loc press to better fit and not chew up ECT connectors. #2-2/0 connectors are especially rough to get done properly. Seems the set screw that's the same for a 4/0 one doesn't like to countersink as it would for the larger size when torqued to the proper amount on 2/0. Pain in the rear because all it takes is a bit hanging over and the boot won't fit even with the press. Than in installing and over-torquing there are the screws that strip. Last week I had to grab the grinder on some set screws just to make them work as they would not go in further and would never come out again.

    ECTs are tricky in the nylon set screw also. Had a lot of them break when installed just slightly out of alignment. Pain in the rear to remove than. Interesting that they are labeled for type W cable still. I don't know of anyone using it over SC anymore - thus cutting the boot one size smaller can be a problem if proper instruction isn't given.

    So I'm still open for another solution.


    Silicone is a good idea. I never much worried that myself. I don't think this connection is supposed to be more than water resistant. Probably not necessary for my application as nobody has brought it up with any (old/new) style of connector. Vulconized ones seal really well and last forever. If they were not such a pain to do, I would go back to them. Rhumer is that we still have the machine somewhere. During the last Sting NYC out door concert, they had a slight problem with rain. I'm fairly certain they got the feeder off the ground and wrapped them up well. Only things that came back worse for the wear asside from mud everywhere was a few Veam Soco connectors that provided their own light show and welded together - another part of my wall of shame - one of the ones that I was able to persuade apart.

    I can see the moisture seep however, but with either style. I think rusted set screws would be common to all given the same age. The person that tought me had the idea of using 16ga steel tie wire to retain the jacket. Ever since, when ever I open up one of those plugs to replace a boot I see a broken and very rusted tie wire.

    What do you "slide" the boot with? I usually use alcohol, but occasionally get lazy with the WD-40 myself.

    On the whole, doing feeder for a day isn't on my top ten fun things to do. That's what the newbees are for.
     
  13. wolf825

    wolf825 Senior Team Emeritus Premium Member

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    Hi Ship,
    I like the ECT connectors for their connetions...not as much a struggle to mate together IMO. To better slide the boot I have used WD40, I have used rope-lube--the stuff you use for pulling cable thru conduit, but one of the better things I have found is been Armor-All rubber treatment..the stuff you buy at car-care centers for tires and dashboards. Another little point I like about using armor all is treating the actual boot ends that mate together--they then seem to slide together a lot easier--no rocking or twisting to get them to join. Some of the older style cam lok originals can be a wrestling match to get them to mate up sometimes. Little armorall and thats relieves the problem.

    I don't like using the set-tool to slide...it seems to chew up the boots a lot and if its not lined up perfectly can twist the brass connector. My solution is that I'll take the mating brass connector to the cam I am building (just a spare opposite sex brass connector--not the boot too) and attach it to the end I am seating and use that as a "handle" and press it in manually. With a good lube its not that difficult surprisingly. Only exception to this can be with 4/0 cable which can be a bit of a workout...but for me its still easier. For me tho I like to slide and seat the cam into the boot by hand cause it allows me to (using the opposite brass end as a "handle") turn and manipulate the cam into the connector with better control so it seats correctly.
    I was never a fan either of the little "sticks" that go in to keep them in place, but the set screw that is nylon--once you get it in put a drop of hot-glue over it and it will never fall out. Use an ice-pick or mini-jewelers screwdriver to line up the boot and the set screw if its torqued a bit to one side, or else it will not seat itself right and it will strip. If you ever need to get to it the glue just peels up. My only huge complaint with cams has been that the allen-key set screws inside seem to be just one turn too short sometimes... When using them on #6 or #4 cable--you just cannot get it tight enough and snug on the cable & copper wafer/wire without popping the set screw past its point and then getting it out means taking it all apart again. Ugh... one solution I found was to double the copper wafer, or do a fold-over at the point where the set screws will go.

    Putting one of these together has always been something I have enjoyed showing the newbies... When I first cam accross these years ago and was taught how to do them I learned many differeing opinions..especially about how to wrap or use the copper anchor wire--or in some folks opinion to NOT use that (wrong). This would make a great little picture tutorial to add to this board..I have a bunch of un-assembled boots too. Tho I doubt many high schoolers would ever end up making these until they hit the work-force. I am also soldering a bunch of XLR connectors for a new sub-snake I am building soon..I was considering snapping digital pics of the proper way to solder and mount XLR's with heat shrink etc. I think this board need a lot more tutorials and stuff ( I am in the process of re-writing my "sound & sound system basics 101 class" I teach into a tutorial article I hope to post to Dave soon for the tutorial section) and I'd be glad to do picture demo's and contribute articles...but again it comes down to "what do folks want to learn most?". For example: The tutorial on how to build a cable is a great start and a very nice guide..tho one bit of info I would add to it is that SJ and SO cable techincally have "male and female" ends in the cable--IOW if you cut the cable you will see that one one end black wire is on one side, and if you lay the cable out flat you should not have to twist over white or green to make the connections--it just means you're using the wrong end of the cable for that sex of connector and to flip it over. A little picky and anal-technical cause it really doesn't matter as long as it is wired correctly, but its still a true fact. :) :) A few of my idea's is stuff like how to take a measurement with a multi-meter, electrical do's and don'ts, how to build a two-fer or 3-fer, soldering basics, wire DMX cable, various testing tutorials, basic knots everyone should know, how to clean/assemble, fix & bench different fixtures, plus basic guides about parts of leko's, fresnels and so on, how to write a cue or effect or do other things in an ETC board (others with access to Strand or older boards could do similar), How to test speakers with meters, set EQ's, proper mic-techniques, and many other things have been floating in my mind as really cool to do.. Plus since we are in maintanence mode at the shop for the next two months, its coming up that we will be servicing our moving lights soon, and I was thinking some how-to-clean picture tutorial would be fun to do...but then how many folks have movers and not know how to clean them? Maybe just a description of how moving lights work and pics of the insides? I dunno..just not sure what is of importance or priority to those reading to learn, what this board wants to do, or if the links that are out there are all that is desired. Hmmm....

    BTW--I have a great lamp that blew the other day--an FEL that blew a huge bulb of distorted glass on one side like a tear-drop. Very pretty. A local shop has a similar wall of shame--the best one they have is the 1k socopex end that they ran 3k of juice thru on a show, and it melted/welded itself at the dimmer-end into a figure-8 from overheating. It was figure-8 at the rack and just melted itself stiff. I wish I still had pics from a few years ago of a moving light (MAC500) that was dropped 18-feet from a beam to a concrete floor because of stupidity during a strike. To our surprise--the lamp did not break..everything else did and was destroyed, but not the lamp. Gotta love those irony's... :)

    happy 4th...
    -wolf
     
  14. Reggie

    Reggie Member

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    Re: Power distribution questions

    A few questions...
    If you are tying in to a panel using tails, what would you terminate the ground and neutral leeds with so that when you tighten the neutral or ground buss screw doen it doesn't completly crush/damage the type W or SC wire?
    I've done several tie in's to live panels through breakers. I have always felt that was safe if standard precautions are taken (gloves, rubber mat, use one hand, etc.). If you are faced with a live panel which can not be de-energized because of known or unknown loads, do you just refuse?
    I watched as NYU film school student did a tie in (his first!) to a live three phase panel. He was using tails with Tricos. No attempt was made to de-energize the panel, his only protection were leather work gloves and a cord tied around his waist that was held by another student. I was just a curious onlooker at the time and could do nothing but comment on how I didn't think this a "good idea". Any suggestions on how this could have been done more safely?
     
  15. wolf825

    wolf825 Senior Team Emeritus Premium Member

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    Re: Power distribution questions

    <center>
    ********************
    ATTENTION STUDENTS
    NEVER TRY TYING IN POWER EVER--it is EXTREMELY DANGEROUS and should be LEFT TO EXPERIENCED PROFESSIONALS AND TRAINED ELECTRICIANS! NEVER EVER CONSIDER TYING INTO A LIVE PANEL EVER!!!! The information provided here is for INFORMATIONAL PURPOSES ONLY and is NOT a TURTORIAL or LESSON on HOW to tie in high voltage power!!! There is WAAAY Much more to consider and KNOW before tieing in power--and that is NOT covered here. Leave it to the Professionals, PLEASE. Its YOUR LIFE.
    ********************
    </center>

    Hiya Reggie,
    First a few things--I need to state for others reading that Power tie-ins should be left to licensed or venue staffed electricians to do--not to tour crew or a show staff. For Liabilty sake AND for safety being the main reasons--you may not know that panel and you risk everything when you tie into a strange panel that you HOPE is wired and done correctly. For all you know in that venue--that 100 amp panel may also be chained thru to another 100 amp panel that is already in use--YIKES!! It may be a delta phase panel and not labeled correctly! You NEVER know...so ALWAYS have a electrician or house / venue electrician tie you in if possible.

    Further about your questions, Trico's like the older Tweeko's, are no longer acceptable or meet electrical or fire code requirements for power tie ins, and should NEVER be used EVER for power tie ins anymore. NO fire marshall will ever approve Tricos or Tweekos for show-power. CAM-LOK connectors are the only acceptable rated connectors in use today becuase they interlock, connect and are water-tight. Reason being for Trico's and Tweeko's is their ratings and clasping mechanisms are NOT true or rated, nor reliable and can slip and are unsafe and do not "lock" securely. Bare-wire tails to Cam Lok are acceptable. Additionally it leaves the clamps over- exposed to arcing & slippage, and to use most tricos, means you have to leave the panels OPEN cause there is no other way for the connector to fit. That NY film student tying in live with trico's was NOT a good idea as you suspected. Good Call on being an observer only. In fact it was overly stupid of this NY student--and ANY teacher who taught him how to do that should be beaten, and loose their teaching license to be around students. Leather work gloves will do NOTHING to protect you from electricity. Leather is a SKIN, rubber is the only acceptable non-conductive insulator, and even then rubber gloves is not 100% for insulation on high power--gloves of that standard are RATED for certain voltages. The cord tied around his waist will also do NOTHING but provide a conduit for electricty to flow to another student--VERY dangerous and TRUELY Stupid. If this was an IATSE house--you would be BANNED from that building forever for what that student did. You NEVER want anyone else to be connected to the person tying in. For those wondering WHY a cord was tied to the other person--the theory behind it is it was to "yank" the person tying in should they get electrocuted and pull them away from the power--that idea doesn't work tho... Long ago we used to carry around a 2x4 for the same purpose--if someone is getting zapped, you smack them with the 2x4 to break the connection--however getting hit with a 2x4 will probably kill someone and do more damage if the electricty doesn't do it. When someone is getting zapped with that much voltage all their muscles contract and stiffen and they become like stone--a persons grip will be constricted and either grab hard or let go themselves--it canot be predicted...thus it becomes very difficult to remove them and unpredictable to say what will happen from the electricity. As for others reading who are wondering as to why you only use one hand with this method on live tie-ins--the idea being that you provide a straighter path for electricity to flow to by only using one hand and keeping the other at your side--so the electricity will flow thru your arm and down your leg to the ground. If you were using two arms--say one was leaning up against the wall--the electricity would go thru your heart to go out your other arm to find its ground..and it keeps you from doing something natural as like grabbing the panel for support (GROUND) and completing a circuit while you are in contact with the LIVE end. Again--its a safety thing but overall IMO it doesn't matter as your risk of dying is equally great in either situation.

    On to your other questions--FWIW and Ship can probably correct me if I am wrong, type W cable (type W rated at about 2000v if I am correct compared to 600v for type SC), is welding stock cable-and not neccessarily the best choice for cable to use for feeder IMO--since type SC cable was made specifically for the Entertainment Industry for this use. While almost identical in properties, I believe there are significant jacket, temperature and conductivity differences that make SC the better safer choice then the welding stock cable. To tie into a breaker is somewhat safer then tying into a live panel for the reasons that you at least have a "breaker" that will disconnect power (and I hope you are turned OFF on the breaker whil you are attaching your cable). When confronted with a panel that cannot be de-energized for tie in and you have to tie in to the buss bars, the best and safest thing is to REFUSE. Its YOUR LIFE you put at risk--and you have to ask yourself is this show worth that?? ANY sub-panel can be de-energized...and if you have a panel that cannot, then a second fused and rated sub panel next to it that can be turned off and on should be installed for use for tie ins by a licensed electrician. Now here are a few things to consider when doing tie-ins--for example if the 100 amp panel you are tying into is LIVE and feeding other breakers circuits and areas of the building, and you need to say tie into it so you can have your 50 or 100 amps, the power and amperage you need that has to also account for the power already being drawn by the other circuits in that panel. If you have a 100 amp draw on your lines alone, and a full breakered panel that is pulling 100 amps already to feed the building circuits, you are exceeding the rating for the box, the buss bars, the panel and the feeder cable that is powering that panel and creating a major problem and hazard of overheating. ANY fire marshall will look at that and shut you down and FINE you severely. Additionally--when you tie in, another consideration is how your insurance will look at what you are doing should a fire or problem arise? If you did it knowingly and exceeded the ratings, and someone got hurt or killed--they would drop you like a hot rock and YOU would be liable..especially if you are not a licensed electrician. Aside from your life--you have to think liability and calculate other power consumptions on live breaker panels. Always ask for a designated fused/switched power panel for you to tie in to and can TAG & LOCK OUT when you are done. Now--the real world says that you won't always get that...and the real world does say you have to find ways to do things that are still safe and acceptable. The BReaker is the best safest way for any kind of live tie in--provided the breaker is "snap in" and does not require you to screw the breaker directly to the live buss bar. Square D's are great for snap in breakers...of course this also means you have the knowledge to see and look at a panel and tell what type of breaker it uses, its amperage and load already, and it has the room and space for you to add your 3 pole breaker. Lots of stuff to consider..and that is just the tip of the iceburg...

    If you are squashing your cable or damaging your cable when you tie in on the nuetral and ground, then your lug is too big or your cable too small.. I would dare say your cable is too small. When that happens--an acceptable "trick" is to strip your cable back twice as normal, and fold it over and insert it into the lug--making more wire and contact in the lug. This gives more wire in the lug so you get less squashing--however you should also know that you do not need to wrench down on the lug so hard that you are squashing things. It needs to be tight, and you need to be able to tug and pull on the cable hard and not have it slip or pull out of the lug...it does not need to be immovable, just very snug. All I can say is it takes practice and experience...I've seen folks stand on the allen key to torque the lug as hard as possible--this is overly excessive and not needed, and can BREAK or strip the lug off the bar--which leaves you without a lug. You may also wish to carry your own lugs suitable for your cable and simply attach them to the neutral and ground bars. That is a lot simpler then trying to make a #1 wire fit into a 4/0 hole. Also a good rule of thumb for tails--is to trim your tails back to new wire every 10 tie-ins unless you tape your tails--and then you could go a bit longer. Over time your expeosed tails will get pinched, fray and turn black from oils and corrosion. Taping your tail tips with e-tape after each use will extend the life and usability of the exposed copper.

    Given your post--I am nervous about what you are doing somewhat--but I do see that you are NOT stupid and I see that you understand breaker tie-ins are safer vs live tie ins on live buss bars. So I would like to make sure you are doing things correctly or at least SAFELY. Can you tell me more about what you are doing and your set up? What cable are you using--what guage, lengths etc, what amperage do you need that requires you to tie and and is this for lighting or sound? Are you feeding to your own distro / breaker box or directly to dimmers or power for amps? Do you know how to identify panels, 120/208 or delta panels? Where do you run into panels that cannot be de-energized? If you run into a panel that does NOT have lugs on the buss bars at the bottom (not all of them will be set up that way) WHAT do you think you should do?? Some breaker panels are not set up to do power tie-ins...

    Safety first and foremost when dealing with electricity. Final rule is if you are at the LEAST bit uncomfortable in doing a tie-in--STOP and DO NOT DO IT. I did my first live-panel tie in well over a decade ago and done about 100 since...but very rarely will I do that today and I will never encourage it to folks who have never done one. Most venue's are set up for code and safety now-a-days--and liability sake I always preferr and deferr to the venue electrician to tie me in while I observe to make sure HE is doing it correctly and to how I would deem acceptable. I saw one electrician bypass the main neutral lug for tie in, so he could separate my feeder wire into 4 little bundles which he could then connect into the smaller bars that are set up for individual wires--after a slight argument that I didn't want him to do that micky mouse BS, he agree'd and complied with my wishes--so always watch your electrician. But as for live tie ins today--Either I have learned more or just realized more the dangers and hazards of doing them live, or just grown tired of putting my life on the line for show power.
    Lastly, I also trust that you know the correct proceedure for tieing IN and tieing OUT of a panel--in terms of which cables go in which order...and WHY that is so? For your student friend to have done this more safely would have been to refuse and require that a proper panel have been available for proper tie in. The use of Tricos, the use of the cable (I HOPE it was a rope and not a mnetal wire or cable) and the fact that he was doing this as his FIRST tie in and it was LIVE tells me you are in a dangerous haphazardous group of stupid idiots, and you are the smartest one there to NOT do it and to question the proceedures you witnessed. Sorry if thats blunt to your friends--but I've seen quite a few folks be STUPID around power and get killed.. Only way to do it safer was not to have done it at all.

    Hope this helps..I will be glad to discuss this more and help answer your questions and guide you in your understanding. However this is NOT a lesson or license on how to tie in high voltage--this would simply be a correction and checking of your current proceedures and to educate you more if you are doing something potentially hazardous you may not be aware of. I would also encourage that we take this to Private Message for further details and not give the younger students who may think they are invincible any bad ideas. Hope this has helped you so far...

    cheers,

    -wolf
     
  16. Reggie

    Reggie Member

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    Tie in thru Trico are pretty common for small film location shoots in the NYC area. Especially for non-union independant production companies. Most rental houses can provide them when you rent a power distribution package. Yes, it leaves the face of the panel open, reasonable precautions need to be taken to keep people away. The front of the panel is usually draped with a rubber mat. Yes you can easily overload the panel and its feeders if you don't make load measurements first to see IF the panel has any excess capacity. Having a sub-panel installed is probably out of the question, it would be probably be cheaper to rent a generator.
    The only instructions the NYU student may have had might have come from a book, I don't know. The cord around his waist was a nylon sash cord, a stout rope might have been more suited to the task. I believe the electrical code reads that the work be performed by suitably trained personnel.
    Regarding my neutral or ground termination question, yes, I am aware of the trick of doubling up or folding back the conductor when the only hole or lug available is too large. What I was asking was if there was a specific or "custom" designed termination that could be crimped or affixed to the tail to prevent damage. I thought perhaps that something unique existed that would not be stocked by an electrical distributor.
    I am currently using #2, type SC, camlok tails to a breakered distribution box. Connections are made in this order: ground, neutral, hot, hot, hot, disconnect: hot, hot , hot, neutral, ground. Am I an expert? No. Will I ever have all the answers for every situation, probably not.
     
  17. ship

    ship Senior Team Emeritus Premium Member

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    “On to your other questions--FWIW and Ship can probably correct me if I am wrong, type W cable (type W rated at about 2000v if I am correct compared to 600v for type SC), is welding stock cable-and not neccessarily the best choice for cable to use for feeder IMO--since type SC cable was made specifically for the Entertainment Industry for this use.” - Wolf
    Nope, while type W is a major pain in the rear because it does not twist as well in making the CamLoc connection, it’s still type SC or W for use on stage by NEC 2002 as far as I know. Welding cable and type SO for feeder are the ones not to touch because they when cut or abused given the amperage are really really dangerous. Type W on the other hand is really really hard to cut much less twist. It’s even more resistant to damage than type SC. Often you will find that in short tails ends or rack to rack jumpers, that with a type W cable, it’s so resistant to cutting that it will unlock itself from the connecter it’s attached to because it’s jacket is so resistant to twisting much less cuts. That in addition to most type W cable being past it’s service life is why people don’t want it around. Something about W not wanting to remain in the locked position because in most instances of cable 5' or less it will not stay. But according to the NEC, for feeder, it’s still ok.

    I love to install ferrules on my tails. Think about a big ½" wide bolt clamping down onto a ½" thick wire that’s within a 3/4" outlet. What do those strands of wire want most to do except escape the bolt clamping down on them? Current travels down the circumference of the wire, any interruption of that flow means more resistance. Ferrules prevent the wire from falling outside of the direct clamping power of the screw bearing down on it. In other words, while not a uniform standard for use or required, it’s the method I use when possible. As for pressure, I don’t remember the exact amount, but think it’s similar to that clamping pressure required for CamLocs at 120 Foot Pounds. Go more than that, as studied by EC&M, and there is more resistance thus heat to the current flow. More than that and there is also resistance. When a wire is hot, it expands, when cool, it might seem loose but when expanded if over tightened to compensate for a seeming looseness, might also cause resistance in being too tight. 120# is an experience thing to achieve constantly the same on site and without a torque wrench. People without this experience just as someone tightening the belt on a band saw will overcompensate and think it’s better that way.

    In other words, I totally agree with Wolf in principal if not application. Without the experience, it does not matter how well you understand the wiring, you can easily do as much damage to the system as without training and doing it anyway. Not sure how I feel about current traveling down the rope, it’s non-conductive after all but Wolf’s statement might have merit given nobody uses that method that has experience with live tie ins. Yea, I have someone with a broomstick around and observing me, if working around live current. I want off the circuit and don’t care about the disadvantages of a 2x4 in the gut. I have had EMT conduit actually melt into and bond with the skin in the palm of my hand while all alone and doing something stupid I tried to fold some wires and shove them into a conduit in getting the coupler back together. Stage lights kind of dimmed and browned out during the live show as noticed in the booth, circuit breaker never flicked itself off, and it took a extreme contuse effort on that in theory 20 amps of current passing thru my body to release the conduit I was touching. That was a 20 Amp circuit - at least in theory given the CB malfunctioned. What would happen should I become a ground path for a 400 Amp circuit I would not speculate at. His tips about the current not traveling by way of the hart are accurate in saving your life and only getting the copper welded to your skin. Given someone pushes you off. That said, when working with live current, not only am I careful, use 10000V insulated tools around them, but I have someone about that will push me off in addition to keeping the hand at the side. Or at least not touching something that can conduct. It’s also a question of what boots I wear. Sneakers breathe too much, so do many work boots. I want myself to be other than the path of least resistance.

    On cable into a large lug, I just installed some #2 wires into some 2/0 feeder CamLocs on a small AC Distro I built yesterday. I agree that putting wire smaller than the lug is a bad thing - even if a ferrule is used in this case. I filled the CamLoc with some strands of #6 THHN to occupy the space. Folding feeder wire back on itself is not an option. Good for smaller wires such as fitting a Leko’s #16 wire into a 12 ga ferrule, but it will not work with feeder cable if for nothing else but the bending radius of the wire is larger than will fit in the hole. Speaking of trimming or adjusting cable for a hole, don’t trim the outside of a wire to fit into a lug, if anything and absolutely necessary, trim the inside conductors because they are not carrying the main load and there will be at least slightly less resistance. As for being acceptable for feeder, given the double neural feeder debate, much less the fact that given a normal lug, it’s normally the same as the hot lugs, I would question what is the neutral conductor size.

    Beyond this all, if you don’t absolutely have experience and training with tie ins - live or not, as with what Wolf says, don’t mess with them. You are not going to suffer from a pay cut and it’s not going to hamper your career. You would not repel down a 80 story building in the middle of a winter storm to focus lights, why would you be tempted to mess with tying in the load which deep down you know only very trained professionals should be trained in. Ya know this, trust in what you know not what your ego says about your ability until you are doing it under the direct supervision of the old man of the theater in training you for it to the best of his abilities. Than even don’t be messing with this stuff unless it’s absolutely your job and you know what the heck you are doing - and I mean that. Wolf’s “uncomfortable - stop and do not do it” is very appropriate on energized and non-panels. I’m personally never comfortable in tapping much less wiring to live panels and I have the training and tools. It’s all a question of being real verses cool. Yea, you can wire to a breaker and it’s all good. 20 years later when someone gets killed because you did not have the tension right do you dismiss it as one of your earlier works, or do you sweat the day something like that happens? Wiring to house electrics is not a tech person’s job. Don’t do it until you are at not only a pro, but I would state an expert and say master level. I do this stuff as part of my living. I have to given my position at the top, but I would also say no, and easily do this were I not specially trained for it and had I not been studied and practiced enough at the technique to sleep at night. Watch those doing the tie in to learn from them and ensure they do it properly, but don’t attempt it. Wrong union buddie!

    This thing is not an us and them debate, it’s one of experience. Wolf and I do this, but when possible and more dangerous than we are prepared for, we get others and observe them at it. “If you are tying in to a panel using tails, what would you terminate the ground and neutral leeds with so that when you tighten the neutral or ground buss screw doen it doesn't completly crush/damage the type W or SC wire? “ - Reggie, I expect you understand what we say and were just looking for an answer. The answer is ferrules and or copper foil making the wires as if one solid part. That and de-oxidant coating the wires to ensure that any oils in your skin or other contaminants will not cause resistance to the flow of current. Do I do it all the time, ha. Not as much as my own Old Man of the Theater advises. Gimmie a break, on the other hand my wire is wrapped more than his has been over the years. I even bought a crimp tool specifically for ferrules to smash them tight around the wire last week.

    I don’t do much in the way of shows anymore however. On show electrician’s, they don’t use a rats nest of already clamped wire for the most part. If the wire comes out of the terminal nice looking, and they have a few extra moments of care, such people might throw a couple layers of courtesy tape around the stripped wire to ensure it does not get banged up and no longer able to fit into a terminal. Otherwise, and as I used to do, we are paid enough that when doing the tie in, we can afford the proper cutting and stripping tools for heavy gauge wire, and thus strip a fresh end to put into a terminal. Foil strips would be nice to act as a ferrule, but at least the goal for the most part is to ensure that all the wires get into the clamp, and there is a distributed pressure on all the wire.

    On school tie ins, yes refuse to do it. Should they try to make you or pend your grade upon it, fear not they are in the wrong unless that specific part is within your training. Heck, when throwing grenades, even I as a person with 6 years in and a Sergeant had someone in the pit with me to if not ensure I threw it, that person would at least kick it into the safety hole in the pit. What is getting electrocuted any less dangerous than throwing a live hand grenade? Refuse but do it diplomatically is the wisest course of action. Someone tells me to tie in, I still ask permission from the house electrician, and only than if the most qualified, and the person properly trained for it do I attempt it given it’s within my honest ability. Sidestep any part of this and you, your company could kill someone including you, if not do other things bad. You are wise.

    Gloves if “Hot Gloves” are smart, A hot mat is also wise, proper tools etc. but without the proper supervision and training that’s all Nintendo over Artari game systems. Safety is what you are being supervised and trained in. Good for them if they have all that and proper instruction. Go for it while supervised and trained in it. If you do not feel comfortable, talk and train with the instructor than if better try again. It’s good training if kept within perspective - but only something to do once honestly ready for it.
     
  18. ship

    ship Senior Team Emeritus Premium Member

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    By the way, there are also crimp on lugs for use in tieins. Depends upon what type of system you are tying into. I stock some clamps that I pre-attach to the cable for tying directly into buss bars, otherwise, should I need to, the shop has a proper crimp tool for all lugs such as 4/0 in making a solid lug to terminal should it be needed. But as for a standard for the industry, nope, not even foil over the wire is uniformly used. Best answer is to cut a fresh section of cable and get it into a lug that's properly sized. Ya, sound as if your training is getting there, that's great, I only wish more people could get instruction proper in this before they have to attempt it on the fly. From my experience, there is no standard for the entertainment industry. Talk to your instructors and see why they think that is and the reasons for it because your question is a good one. I certainly would not mind good connections. Part of that might be that the terminal clamping down on the wire deforms it, and it's not good to re-use that stressed part, another part might be something like it just not being practical. Eventually, given more studious people like you asking such questions, there might be a industry standard. As yet, not anything that would be proper - one of them grey areas.

    As for Traco or Twekos, get onto ProSound Lighting Forum and read what Craig recently said about the NEC and Twekos. That's the primary reason for not using them anymore. Takes a while for rules and industry standards to catch on. Are you safe in saying no to using antiquated equipment, much less stuff that for the most part is safe when used properly, but still can be unsafe? That's and ethical and experience question that is often best to learn from bit frequently to do. Use the old method only if under direct supervision and direction from someone that knows how to use it safely. There is a lot to learn by old techniques. Should you not have such people, than the answer is a definate no.

    Hope that answers the question more specifically. Is it a perfect industry, nope. Go to page 189 of the backstage handbook and look at the "Stage Plug." I was using them and their older version in a 30 amp - non grounded socket only 7 years ago. Did it work yes. Did I have reservations and was I extra careful, you bet. More important, did I learn stuff given proper supervision in using them? Yes.
     
  19. dave94089

    dave94089 Member

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    Have you looked at this book?
    Amazon.com: Electricity for the Entertainment Electrician & Technician (9780240809953): Richard Cadena: Books

    Also, this is free and available for download:
    http://etcp.esta.org/candidateinfo/electricalexams/docs/ETCP_Electrical_Handbook_V1.4.pdf

    Hope that addresses your need for formal training materials.
     
  20. gafftapegreenia

    gafftapegreenia CBMod CB Mods

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    Necropost warning. This thread is from 2003
     

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