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Author Topic: specifying booth electrical service Scott Norwood Film God Posts: 8146 From: Boston, MA. USA (1774.21 miles northeast of Dallas) Registered: Jun 99 posted 06-16-2010 12:05 PM                        This is for a community theatre that is in the process of renovating to become a multi-use facility that will open next summer. I am tangentially involved with this and have been advising them on all things film (though the primary purpose of the venue will be live stage and music performances). Their booth is being re-wired, and the electrician needs to know what type of service to provide for the film projectors and related equipment. The booth will also include amps for the house system (also used for live performances), other sound equipment, and some sort of lighting equipment, all of whose requirements will be specified by others. The booth will have three-phase power. Lamphouses will be 2.5kw, probably Super Lume-X with Strong rectifiers (probably switchers, but not sure yet), but they have not been purchased yet, and exact models are unknown. Projectors will be Centurys on Simplex soundheads (this is what is already there). This is a bit out of my league, but here is what I have come up with so far. Any comments or clarifications would be appreciated. Circuit list should include the following: - ceiling/work lights (120v/20a) - wall outlets (120v/20a) - roof exhaust (?v/?a) - projector #1 motor (120v/20a) - projector #2 motor (120v/20a) - electric c/o (120v/20a) - threading lamps/LED power supplies (120v/20a) - cinema processor and booth monitor (120v/20a) - rewind bench outlet (120v/20a) - video projector (?v/?a) - video monitors (120v/20a) - other video (DVD player, switcher/scaler) (120v/20a) - hearing-impared system? Questions: - is there any reason not to specify a separate electrical panel for the film equipment? (I am concerned that the booth will be used for other purposes, and that non-projectionists will touch things that they should not.) - how much power should be specified for rectifiers, and how much heat do they produce (worst case; rectifiers will be in the booth, as there is no separate rectifier room)? - is there any reason not to use a common ground for all projection and sound equipment? - how should the load be distributed amongst the 3 phasess? should all sound equipment be kept on its own phase? - does anyone run separate circuits for sound c/o relays and/or motor-start relays? - does anyone prefer to mount LED power supplies in the rack instead of on the sides of the projector bases? - should I be scared of having lighting equipment (dimmers?) near sound equipment? - is there anything else that the electrician should know to do or not do? I realize that this comes dangerously close to asking for free consulting, but the budget is minimal (I am not being paid for my time, either), and I would prefer that they avoid making expensive mistakes. My only reason for involvement in this is the hope that they will put on an interesting film program on nights when there are no stage performances. Any ideas/advice/suggestions would be appreciated.  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 06-16-2010 12:42 PM                     I usually have a seperate panel in multipurpose rooms for each function 200amp 3phase for projection 100amp for the house soundsystem if it is a small room the dimming panel will depend on the number of dimmers and capacity installed also in many locations the code requires a 3 phase 400amp panel on the stage with its own feeders for road show Also i recomend each panel have a seperate transformer feed and dedicated ground  |  IP: Logged Demetris Thoupis Phenomenal Film Handler Posts: 1240 From: Aradippou, Larnaca, Cyprus Registered: Apr 2001 posted 06-16-2010 12:51 PM                     Gordon is that a typo with 200 Amps? Feed from Electrical panel to Projector Console needs no more than 20-32 Amps and still that is more than enough.  |  IP: Logged Scott Norwood Film God Posts: 8146 From: Boston, MA. USA (1774.21 miles northeast of Dallas) Registered: Jun 99 posted 06-16-2010 01:29 PM                        Thanks, please keep the advice coming. I'm not concerned about wiring for sound or lighting--those will be specified by people who know more than I do about those areas. I want to make sure to avoid possible ground loops and interference with the cinema system, but otherwise trust what will be done with those other systems. If sound and film use separate panels, should the cinema processor and video equipment be run off of the sound panel or the film panel? I assume that they will not be hiring a projectionist for every video show, and I would like to keep untrained fingers away from the film equipment panel as much as possible. On the other hand, none of that equipment will be needed for most events. Also, do I want 3-phase wye or 3-phase delta?  |  IP: Logged Rick Raskin Phenomenal Film Handler Posts: 1100 From: Manassas Virginia Registered: Jan 2003 posted 06-16-2010 04:36 PM                     I think quite a few of the general purpose circuits (wall sockets, booth lights, booth monitor, etc.) would suffice with 15A breakers. Not much difference other than the 15A plugs are considerably cheaper than 20A and you can use 14 gauge wire instead of 12.  |  IP: Logged Robert Minichino Master Film Handler Posts: 350 From: Haskell, NJ, USA Registered: Dec 2005 posted 06-16-2010 04:50 PM                        As long as you have more than one receptacle on the circuit, you can use standard 15A receptacles on a 20A circuit (duplexes count as two). I also prefer using 12ga for all circuits to minimize voltage drop. You want 4-wire 3-phase Wye (120/208Y).  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 06-16-2010 06:20 PM                     The panel should be 200amp in canada at least the electrical code requires all comercial buildings to use 12awg for outlet and lighting wireing even at 15amp The cinema sound and video should be on the projection panel stage audio should be a seperate panel and stage lighting again a seperate panel again in a perfect world each of those panle would have there own transformer and dedicated ground  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 06-17-2010 07:37 AM                     I have found that a 200 amp panel is not always possible in existing buildings or remodels. I am installing a D-Cinema system today in a building with Delta wiring. I never feed a piece of electronic gear it's maximum rated AC input so I have the electrician installing a step down transformer system so the 240 three phase(with a 210 volt high leg) becomes 208 three phase. In this case the power company would not even discuss a new transformer out on the pole so it left no other alternative. This particuluar pedestal requires but a 30 amp feed to it's built in sub panel. This powers the mid sized projector and all ancillary digital gear.  |  IP: Logged Scott Norwood Film God Posts: 8146 From: Boston, MA. USA (1774.21 miles northeast of Dallas) Registered: Jun 99 posted 06-17-2010 08:18 AM                        Thanks. Since there were no major objections to my original circuit list, I went with that. I'm leaving the grounding issues with the electrician and sound guys. At this point, I'm not sure what is possible or not, but they are doing some fairly major building rehab (including new HVAC and seats), and I would not be surprised if this includes new electrical service from the street. I will have the technician who will be doing the installation sanity-check everything before the electrician starts his work.  |  IP: Logged Gordon Bachlund Jedi Master Film Handler Posts: 696 From: Monrovia, CA, USA Registered: Aug 1999 posted 06-17-2010 12:36 PM                        Scott, I would second Gordon's suggestion re separate dedicated tech equipment panelboards. These should have lockable covers to control access. Also, don't skimp on the grounding as Gordon suggests. It's cheaper to do it right the first time than to troubleshoot it later.  |  IP: Logged Tony Bandiera Jr Film God Posts: 3067 From: Moreland Idaho Registered: Apr 2004 posted 06-17-2010 01:01 PM                     - is there any reason not to specify a separate electrical panel for the film equipment? (I am concerned that the booth will be used for other purposes, and that non-projectionists will touch things that they should not.) No. A separate panel is a very good idea. As mentioned by Gordon S. put all cinema and video in the same panel. - how much power should be specified for rectifiers, and how much heat do they produce (worst case; rectifiers will be in the booth, as there is no separate rectifier room)? A 30amp, 3-phase circuit will work for switchers, magnetic should be the same depending on brand. Mag rectifiers will produce a lot more heat, but you can put them in the booth without too much worry. The natural extraction of air for the lamphouses will help to draw some of the rectifier heat out. MAKE SURE YOU HAVE AT LEAST 600-800 CFM AT EACH LAMPHOUSE STACK FOR EXHAUST!! - is there any reason not to use a common ground for all projection and sound equipment? No and as mentioned, heavier grounds are better and important. - how should the load be distributed amongst the 3 phasess? should all sound equipment be kept on its own phase? Load should be distributed as equally as possible on all three phases, and no, DO NOT group all the sound equipment on one phase. It is NOT necessary if good wiring practices for the audio leads are followed. **IMPORTANT: MAKE SURE ALL AND I MEAN ALL AUDIO CIRCUITS ARE FED WITH DEDICATED NEUTRALS FOR EACH CIRCUIT!! ABSOLUTELY NO "SHARED NEUTRALS" IN ANY OF THE AUDIO OR VIDEO CIRCUITS.** You should have at least 5 circuits for your video/audio system, one circuit for processor, booth monitor, server, one for all the video gear and at least three circuits for the amplifiers. - does anyone run separate circuits for sound c/o relays and/or motor-start relays? Not required, but a good idea so you can cut off power to the c/o's, worklites and aux devices. - does anyone prefer to mount LED power supplies in the rack instead of on the sides of the projector bases? I have no preference. If rack space is available to mount them on a panel so the power LED's are visible, I do rack mount. Otherwise they go in the bases and are powered by the c/o breaker. - should I be scared of having lighting equipment (dimmers?) near sound equipment? YES!! Be afraid, be very afraid. Try to keep as much distance physically and electrically between audio/video equipment and dimmer powers. - is there anything else that the electrician should know to do or not do? Yes. As mentioned, NO SHARED NEUTRALS allowed on ANY of the audio/video branch circuits. Make sure each circuit has a ground wire installed (DO NOT rely on conduits for grounding in this case.) And make sure they install the circuits YOU need and specify in the locations you tell them to do so. There is another thread on here where I go into detail on circuit requirements.  |  IP: Logged Scott Norwood Film God Posts: 8146 From: Boston, MA. USA (1774.21 miles northeast of Dallas) Registered: Jun 99 posted 06-17-2010 01:28 PM                        Answered questions lead to more questions: What does everyone do for worklights? I have asked for a few bare-bulb sockets and a "reel light" on the ceiling for general maintenance, a "bullet-light" fixture next to each viewing port for threading, and two bullet-light fixtures above the rewind bench for film inspection. I have also requested Littlelights (or similar) for the cinema sound rack. Is this overkill or am I missing anything? Should I be scared of asking for dimmer switches on the bullet-light fixtures? Who installs the lamp exhaust blower? Is it the HVAC contractor? Will he know what to do if I give him the specs for the lamphouses and tell him how many CFM of exhaust I need? (MA code minimum is only 300 CFM for xenon, 200 CFM for carbon arc.) What are the exhaust requirements for D-cinema projectors? I seriously doubt that this venue will ever have one, but the possibility at least needs to be considered.  |  IP: Logged Tony Bandiera Jr Film God Posts: 3067 From: Moreland Idaho Registered: Apr 2004 posted 06-17-2010 01:52 PM                     Scott, for worklights I have track lights mounted on the front wall by each projector and they are on dimmer switches, no worries for noise there. I have found rack "littlelites" to be almost useless. You would be better served with a light on a dimmer mounted on the wall nearby and aimed at the rack. The reel light you mentioned would be a great idea for working on the backside of the rack..and if placed correctly it could be used to work on the projectors. Yes the HVAC guy deals with the lamp blowers. He'd better know what to do if you provide the specs, if not he should lose his license. Make sure you show him the exact locations of the drops into the lamphouses too. STAND FIRM on 600 CFM minimum for EACH of the lamps!! I don't care what local codes say, 300cfm is NOT anywhere near enough for anything but a 1k lamp running at 800 watts. YOU are the one who's gonna have to deal with short lamp life, damaged reflectors and burned fingers in the trap if the cooling isn't up to par. And changing it after the fact is super expensive!! OH, very important: The lamp exhaust blowers need to be controlled exclusively by the projectionist with a switch in the booth, and ABSOLUTELY IN NO WAY controlled by the building's A/C system or energy management system!! UC Irvine has found that out the hard way to the tune of over $3,000 to replace a damaged reflector in my Kinotons. Steve or Mark can answer the D-Crapema question, but I think it is closer to 800 cfm and I would insist on a separate exhaust blower for it. Again, if you think it could happen, install it NOW rather than later. Lots less money (and mess) too.  |  IP: Logged Josh Jones Redhat Posts: 1207 From: Plano, TX Registered: Apr 2000 posted 06-17-2010 04:54 PM                        FYI The smallest commercial circuit is 20 amps. I have also noticed that in practice, sound systems that run on the same leg have fewer noise problems. JJ  |  IP: Logged Tony Bandiera Jr Film God Posts: 3067 From: Moreland Idaho Registered: Apr 2004 posted 06-17-2010 05:55 PM                     Josh is correct on both counts, but I qualify his second statement with the fact that if the sound gear is on the same leg it will allow sloppy grounding and audio wiring to pass with out noise. But you will end up with spurious noise issues (if not wired properly that is) that won't show up on commissioning. Another thing to consider: If all the sound gear is on the same phase, any problems on that phase WILL affect everything!! One bad surge, loss of phase (not impossible), blown fuse on that phase, load imbalance (which will stress out the building's transformer and/or distribution gear) and noisy loads on that phase will all have an effect. In power distribution, a balanced load is always more efficient and unlikely to cause problems. A properly wired sound system WILL NOT CARE if it gets its power from multiple phases!! (As long as they come from the same panel that is.) I did live sound for many years and we always fed our sound system as balanced on all three phases and never had noise issues. And this is gear that gets lots of abuse and the wiring changes with every venue.  |  IP: Logged

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