Control/Dimming Simple lighting question...help!? Limited resources...

Discussion in 'Lighting and Electrics' started by ktflem, May 2, 2017.

  1. ktflem

    ktflem New Member

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    Hey! I'm in the process of planning our annual youth camp. We are stepping it up a notch this year and adding some real stage lighting instead of just the rear house lights turned on/off between the worship set and speaker.
    We currently have some large and small par cans that were donated. They turn on/off by plugging them in. No other cords required or able to be used with these. So (I'm assuming) a lighting board is not an option.

    The current plan is to plug them all into 2-3 power strips to control when certain ones are on. Is there a way to control these better? Would really like to be able to fade each individual one as if they were run off an actual lighting board. [Obviously, it's super distracting when the lights just all burst on all at once.]

    Would also like to not blow any fuses in this place. We'll be in the middle of nowhere running off of camp electricity. Though we have considered bringing a small generator since we doubled the size of our band and might have to run a bunch of cables to a board as well.

    P.S. Our stage design will also have some lighting involved. Just some cheap Christmas lights stringed up.

    Any help appreciated!
    Thanks!
     
  2. theatricalmatt

    theatricalmatt Well-Known Member

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    Do you have the manufacturer and model number of the PAR cans?

    Are they LED or incandescent? If they're incandescent (it sounds like they might be), you would need to add one or more dimmer packs and a lighting board -- as well as a control cable(s) between the board and the dimmer(s), and possibly jumpers between the lights and the dimmers as well.

    You're not likely to blow any fuses -- you're already using as much power as having them on at full, nu? -- but adding dimmers tends to lead people to adding more lights, and that might overload the system.
     
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  3. Skervald

    Skervald Active Member

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    You should be able to pick up a couple of simple DJ type dimmers for a few hundred dollars a piece. (less if you look at used models) Depending on how long you'll need them, renting may even be an option. Either way, the PARs will plug into the dimmer. The smallest of these portable dimmers typically handle 4 fixtures. The dimmer gets connected to power, and then a DMX (data/control) cable runs from the dimmer to your board. The dimmer gets a starting address (let's just say "1" for this example) This means the PAR plugged into receptacle #1 on the dimmer is now fixture #1, the one plugged into #2 is 2 and so on. If you have more than four fixtures, you can daisy chain a second dimmer to the first. You'll set up this next dimmer with a starting address of 5. The fixture connected to receptacle #1 on that dimmer is 5, while the one plugged into #2 is 6 and so on. Your simple light board most likely has numbered faders on it. The numbers on the faders correspond to those dimmer channels you set up. The board tells the dimmer how much power to send a given fixture.

    Things to be careful of are overloading dimmers or the circuits they're plugged into. You've already mentioned this so I know it's on your mind. Check your PARs first and see how much power they draw. Then check the dimmers you're going to use to make sure they can handle it (I'd be surprised if you found a problem here but it's best to check). Lastly, check out the circuit you're going to use. Is it a 20amp or possibly a 30? Find out if there is more than one receptacle on it and what else is plugged into it. Do a little math to make sure you're not going to overload anything and you're in business!
     
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  4. seanandkate

    seanandkate Well-Known Member Fight Leukemia

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    A lot will depend on how much power those PARs are drawing. If your plan at present is to plug them all into power bars, you might be disappointed if they all trip a breaker on your panel, or more probably, trip the circuit protection on the power bar. When you add them up, you don't want to go above 1800 watts for a 15 amp breaker. As for the dimming, depending on your comfort level, you could build a control board with household dimmers. they usually max out at about 500w, so if you have a 1K PAR, it's a no-go unless you relamp.
     
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  5. TNasty

    TNasty Active Member

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    If you're not looking to spend a fortune (or even much money at all) you've still got some options.

    One possibility is to use a couple "light switch dimmers", (something like https://www.amazon.com/dp/B000BOA23U/?tag=controlbooth-20 ), and wire them to outlets that are clearly marked "dimmable lights only". Certainly easy enough to set up, and it still stays relatively cheap. One suggestion for this is to not use power strips on the dimmed power line, as the strips might flip off as a protection feature- just use nice splitters (usually in the form of extension cables). You might not want to have one dimmer for each light, but perhaps do it in groups (IE have a "presenter" group, a "band" group, and an "acting" group), the only issue is that you can't have the same light on different groups (or else strange things happen- plan carefully).
    The bonus with the "light switch dimmer" option is that it's essentially putting the electrical stuff in that you'd need if you were to upgrade to an actual dimmer rack and lighting console.

    EDIT: @seanandkate , you raise a good point about power draw. Perhaps see about having an Arduino control some heavy duty digitally controlled variac type thing. At this point, it seems more feasible to just get a small dimmer rack and hook it up to a computer running Freestyler or something.
     
  6. Aaron Clarke

    Aaron Clarke Active Member

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    I second that. The other option instead of installing, is get a some metal electrical boxes and a piece of plywood. Make up a simple board with off the shelf house hold dimmer switches wired to outlets from the home improvement store. Something like the pic, but neater please. I would suggest using SO cable for power in pig tails and conduit to connect each electrical box. I would make sure all outlets, dimmer switches and plugs are 20amp rated. All wiring 12gauge. Its not pretty (it can be if we get creative) but it is a cheap and cheerful way to get a few channels of dimmed control. A simple way to figure load is consider 100 watts as 1 amp. Whatever par can you have the lamp will be marked with it's wattage. It's not exact calculation but is a safe quick way to figure it. Even if you build your board with 20amp parts, I wouldn't push the load past 15amp (1500W) per 'channel' because 12gauge ext cords are expensive and if you are borrow cords from friends and family they are probably 14 or 16 gauge. I wouldn't put more that 1000w on 14gauge cords and 750 on 16gauge cords.

    Its not the pro way, but it will get you by that one time a year at camp without spending a bunch of money. Also- this is for incandescent fixtures only... If you have LED I defer to other minds.
     

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  7. TNasty

    TNasty Active Member

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    Expanding on what @Aaron Clarke said- The equation for Voltage, Amperage, and Wattage is W=IV (I is Amperage).

    It's safe enough to say 100 watts on 120v is 1 amp, but it's not safe to say 1 amp on 120v is 100w. What I'm getting at here is that you should always round your requirements up, especially when you're talking about electrical work. Example: A 1000w microwave can run on a 10 amp (1200w) dedicated circuit breaker with no problem. Meanwhile, you can't run a 10 amp microwave on a circuit rated for 1000w (about 8 1/3 amp), since the microwave will "want" 1200 watts. Just keep in mind where, which way, and when you round numbers.

    I could dig even deeper into electricity with the I=V/R equation and how you can calculate resistance in a wire, but there isn't too much of a need for that right now.

    If you're thinking of using extension cables at this power level, I'd suggest making your own by getting a regular power plug that you can open up, and running the cable into a metal box (with a metal, not nylon, faceplate, for the love of god) with one or two gangs of outlets. You can use some solid core copper cable so that you won't have to worry about using too light of a wire gauge- you also get the added perk of it being stiff (as odd as it sounds, you'll probably find this helpful when it comes to getting the cable to lay flat on the floor or to just stay in place). You can pick up a 500ft spool of 14 Gauge solid copper wire from a home improvement store for about $25, not sure if that's for the 3 conductor (Hot, Neutral, Ground) I'm talking about, or if it's just for a single conductor. The hardware to make one of those extension cords with a receptacle would run about $10-15 if I'm not mistaken.
     
  8. Aaron Clarke

    Aaron Clarke Active Member

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    I'm not sure sure about using copper "romex" style, or any conductor designed to be in conduit, as a temporary power run. It is to easily nicked and damaged when exposed to foot traffic and such. Can you, yes, should you, not in my opinion. If it is temporary, I think it is going to be a pain to pull and store. I think you are better buying/borrowing 14g outdoor power cords at least. If you look around you can find ones that aren't neon colored. I have found some that are dark green and dark red that are pretty inconspicuous or, in a pinch, can of flat black spray.

    thanks @TNasty for expanding on the math expansion. And yes, for the love of the holy spirit, use metal boxes and cover plates.

    I think since they are going form NOTHING to a few donated par cans 3-4 of these home made dimmers is going to be night and day. 4 would get you control for a front right wash, front left wash, on stage (Christmas light) and 4th one free for a special or two. To build it maybe $75 all said and done. If you can't find 20amp dimmers you can go 15amp just don't overload them. Line up your dimmers on the board horizontal (you can just grab a 4 gang electrical box at the store) then grab a stick of wood to use as a grandmaster!

    Addition: This is a great project to learn and practice some basic electrical wiring. If you not entirely comfortably anyone with basic electrical experience/knowledge can help you.
     
  9. TNasty

    TNasty Active Member

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    Ah, the good ol' "straight stick" method.
    I'd personally suggest getting a six, or possibly even eight gang electrical box to allow for some expansion without needing to redo everything. Just get your new dimmers and faceplate. In the mean time, you can use the blank space for something like notes, or install a static outlet to put a nightlight in to appease your light operator.

    It's a code requirement in most areas (if not all) to use metal junction parts and faceplates if any single part of the junction box/plate will not be flush mounted. Sadly, even the slight curve on the front of my stage is enough to make nylon components come loose, but that's a whole other story.
     
  10. venuetech

    venuetech Well-Known Member Departed Member

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  11. Aaron Clarke

    Aaron Clarke Active Member

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  12. TJCornish

    TJCornish Well-Known Member

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    Mr Nasty, this is awful advice. It is absolutely not acceptable using NM/Romex/THHN/whatever is cheap that has wires in it for portable cable use. It's unsafe, very illegal, and probably not cheaper than doing it the right way.

    Your signature line says "electrical engineer", but other posts you have made suggest you are a high school student. Which is it? I find it very hard to believe an actual electrical engineer would make the above recommendation.
     
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  13. TJCornish

    TJCornish Well-Known Member

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    Guys, while home-brew can be fun, this isn't appropriate in the original poster's situation AT ALL. Camp buildings are usually wood and filled with kids. Let's not suggest building stuff - especially with illegal materials and methods.

    Once the bulb wattage is known we can figure out what dimmer is needed. Basic DMX dimmers are not expensive:

    http://www.fullcompass.com/prod/079230-ADJ-DP-415
     
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  14. EdSavoie

    EdSavoie Well-Known Member

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    Since using residential style dimmers has been suggested, I'm also going to throw a cautious reminder that the Lutron dimmer linked is rated for 600 Watts. So if anything you got is Lamped 750W or 1000W that's not going to work very long...

    Since you mention "camp power" I'm also going to give you another thing to think about. (Or perhaps something for everyone to wonder about my supply...) You should probably watch your mains voltage, especially if you aren't using much of the capacity of your available supply. Even in my urban supply in our theatre, I once measured the voltage at a rather questionable 130, which means a linear load is going to be drawing a bit more than expected. (I wonder if this has anything to do with never seeming to get 300 hours from my 750s...)
     
  15. TJCornish

    TJCornish Well-Known Member

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    I strongly disagree.
     
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  16. RonHebbard

    RonHebbard Well-Known Member Premium Member

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  17. Aaron Clarke

    Aaron Clarke Active Member

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    Do explain? Isn't hands on experience a fundamental part of learning? I'm not advocating someone with zero experience try on their own but if there is a teacher or parent involved that has the education and experience to assist in some basic electrical wiring practices. This is essentially basic household wiring and everyone needs to have that experience.

    I'm not advocating its the pro way to do it but if you have and a couple of par cans you want to dim and less than $100 I don't see a reason why it can't be done safely. I respect professional opinions to no end but sometimes I see opinions jump to "you can't do it because its not the way I would or was taught". When properly wired this is no different to plugging a light into an outlet wired to a wall switch. You have to watch your loads and cable ratings and such just the same with portable dimmers. Yes cheap portable dimmers are available and if you have the money for a couple pack, DMX cable and a board of course that's the way to go. Remember the original poster is talking about using power strips or manually plugging in and unplugging the fixtures to turn lights on and off which I feel is far less safe.
     
  18. BillConnerFASTC

    BillConnerFASTC Well-Known Member

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  19. TJCornish

    TJCornish Well-Known Member

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    The OP does not seem to have electrical experience. Cobbling together residential electrical components for use in a commercial situation (see earlier email RE a wooden structure filled with children) is foolish. There are many ways to assemble electrical components such that they appear to work, but have created a very significant danger - either a fire or shock hazard, or both.

    It's one thing to do an electrical project at home and use an Arduino to control your Christmas lights; it's quite another to suggest on a professional forum that folks go out and essentially buy whatever junk that is conductive and fits together, and then get Uncle Larry to help wire it up.

    Guys - I get it - money doesn't grow on trees, but basic DMX dimmers and boards are SO cheap. By the time you collect all the components to do it in an uncertified (and probably unsafe at some level) way, it's not much cheaper if at all, than buying commercial products.
     
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  20. TheaterEd

    TheaterEd Renaissance Man Fight Leukemia

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    Hands on experience is absolutely critical to most learning. That being said, you don't teach someone to drive by putting them behind the wheel of a school bus full of children. The cost of failure is too high. If/When this fails it won't be on a work bench in a lab, it will be in church camp assembly hall in the middle of the woods. Not exactly the most up-to-code location. Picture a fire, even a small one, in a duct-taped together assembly hall in the middle of the woods that is stuffed to the brim with 300 boy scouts and volunteers. You can't count on proper egress or flammability requirements. The cost of potential failure here is far too high.

    While it could be done safely under the proper supervision of a trained electrician, we have no reason to assume that OP is going to actually find a person who is qualified rather than just try it themselves. All we know about ktflem is that she is 25, from Oklahoma, and wants to improve her theater knowledge.

    The only responsible suggestion is to point her towards rated products that help her achieve her desired effect. At least until we know more about the situation. For example, As Ed pointed out without knowing what kind of par cans she has it was recommended that she use a dimmer rated for 600 watts. If she has 750 par cans, or even if she just plugs her power strip into that device, she could find herself in a bad place pretty quickly.

    A beginner with too much knowledge and not enough supervision is a recipe for disaster.

    To the OP. I highly recommend you look into a couple of the dimmers linked by TJ and start researching the many options for controlling them via a laptop. The whole project can come in for less than $300 and greatly increase your production value.
     
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