At my school, we have a total of 9 spot lights, including 4 ellipsoidials, 4 fresnels, and 1 followspot. That being said, we usually end up bringing in some lighting for shows. For the show this weekend, we had to bring in 24 ETC Source 4 Pars, plus dimmers, a temp. power panel, etc. We have 8 channels left over in the dimmer packs, and enough power to run all 8 channels. My question is, is it worth trying to run about 100' of extension cord to our spots from the dimmers we rented so that all of our lighting would be on one board? I would just hook them all together, except that there are three different systems in place. Our fresnels are run with our house dimming system (Leviton system), and our 4 ellipsoidials are run off DMX using two dimmer packs and a Scene Setter 24 controller. The lights we rented run off of NSI Microplex using 3 NSI NRD 8000 dimmers, two NSI DDS 6000, and a NSI NCM 7232 controller. We have the three NRD 8000s connected to the Source 4 pars using Socaplex, and the DDS 6000s are close enough that I was able to use just regular extension cords. Currently, we are only using two of NRD 8000s, but the third is available and has power. What I'm wondering, if it would be worth the effort to run 4 extension cords 30 feet in the air about 50' to the fresnels, and another 4 30' in the air about 100' to the ellipsoidials. Which would allow us to run everything off of the NCM 7232 controller. Thank you!
Question for a show this weekend
- Thread starterJereNet
- Start date
Worth it... thats up to you... Can you do it... yes (with some reservations). 100' cable runs are pretty common and are safe if the load is not overloading the cable. The longer the cable run, the more resistance builds up in the line, and the more voltage loss you have. Resistance in the cable means heat is produced which can cause the cable to fail and start a fire.
So, that being said... if you are using household (orange) extension cords to do these runs, no, you can not do this. If by extension cord you actually mean 12/3 AWG SO cable, then go for it. However, you need to take into account the power loss that you will get from the run in deciding how many fixtures you will put on the end of that cable. If that is over your head, I would suggest you not do it.
Now, the question comes to what will you be gaining by doing this. If you are recording cues into the NSI console (if it can even do that), this could save you a ton of time and hassle. However, if you are hand operating all the console... I would say its not worth your time.
So, that being said... if you are using household (orange) extension cords to do these runs, no, you can not do this. If by extension cord you actually mean 12/3 AWG SO cable, then go for it. However, you need to take into account the power loss that you will get from the run in deciding how many fixtures you will put on the end of that cable. If that is over your head, I would suggest you not do it.
Now, the question comes to what will you be gaining by doing this. If you are recording cues into the NSI console (if it can even do that), this could save you a ton of time and hassle. However, if you are hand operating all the console... I would say its not worth your time.
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Thanks! I was planning on using 14/3 SO cable, with one fixture on each cable. Another thing, is that I was hoping to program cues into the board. Also, I only have two techs for this show, me (tech director, stage manager, lighting designer, and sound engineer), and currently, I'm taking care of sound and the rented lighting. The other guy is doing the followspot and our 8 spots, because of locations (the sound board and rented lighting board are next to each other FOH, while the DMX and house dimmers are in the booth in the back of our auditorium.
DuckJordan
Touring IATSE Member
14/3 will not work you'll likely burn out your cable or start a fire. 12/3 or better for this application.
Please explain how a 575 or 750W load on 14g. cable, even if 100', will "likely burn out your cable or start a fire"? Thanks.
You are quite correct that voltage drop becomes a factor. You'll have less voltage on the end of a long cable unless you factor that in and size the cable accordingly. What's the down side of excess voltage drop? The light will be a bit less bright. There's no harm in that if it does the desired job.
However, I must take issue with the suggestion that a longer run of cable would build up heat and become unsafe. The NEC says that's wrong. The cable's ampacity rating is the same whether it is ten feet long, or 1000 feet long, provided the cable is exposed to free air over the whole length. You are technically correct that more heat is dissipated as the cable gets longer, but the surface area also increases which allows the proper amount of heat loss required for safe operation at the rated ampacity.
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DuckJordan
Touring IATSE Member
The reason I say this is how likely is that cable to be new and without damage and how often are you in a space where free air has access to the cable. Another reason is since it is in high school I prefer to keep a possible issue out by making sure its dummy proof. I can't count how many times I've found regular Orange extension cords attached to 1k fixtures because they saw someone else do it. To me I would be removing as much cable that is less than 12 gauge just to make sure it doesn't get used improperly.
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