This may be obvious to some, but I've been working on theatre lights since the '70s and it's not obvious to me. If you upgrade and install a full LED based lighting system in a theatre, I know the instruments want continuous AC power. The common way I've seen this done is to install theatrical relays which regulate the power and provide breakers for overload protection. Is this just done because the dimmer racks are/were already there and switching over to relays is the simple elegant fix? I'm working with a small community theatre looking to upgrade sometime soon. Our current system is old enough that it is Not dimmer-per-circuit. Wouldn't the most logical solution be to decide which of the current theatrical circuits you want to convert to full time AC and just have those switched on and off from banks of standard Breakers with possibly a Master Switch for each bank? Or is there another reason for the Relays?
Are Theatrical Relays Really Necessary In LED Based Systems
- Thread starterRadio
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Some much more educated people will be along to respond with more info but to start most breaker are not in fact designed to be used as switches. Using them as such reduces their lifespan and might lead to nuisance tripping. And swiping modules is much less expensive (in theory) than the labor to move circuits to a breaker panel.
jtweigandt
Well-Known Member
We have an ETC dimmer rack. I ran off of wall power and extension cords when we got our first LED's. But not wanting to leave them powered on meant walking around the theater and unplugging and flipping switches... So I picked up some used relay modules and replaced a couple of my dimmers with them. Advantage.. I can control the power on power off of the LED's from the booth/board. I just power up at the beginning and park that address for safety. End of the night.. just unpark and power down. Time saver, and it becomes part of the normal workflow, rather than going down to the stage, answering 4 questions the director has, talking to 2 other people and forgetting.. leaving them powered on. If you have a conveniently located breaker box, then wiring from there, and just flipping the breakers at the end of the night migh just be as easy. Not sure about the reduction in lifespan using a breaker as a switch.. Also giving up a couple of stage plugs was no big deal, because 10 new LED's more or less free up 10 conventional stage plugs..
Piling on the previous replies, we also have an ETC rack and have swapped dimmers for relays.
- The incremental cost of a relay when added to the purchase of quality theatrical LEDs does not add much to the overall cost.
- Controlling the LED power using the same controls as the rest of the rig is convenient.
- It cuts down on retraining since the rack, console, and wall stations don't change (for power distribution).
- Electricians are expensive. Swapping a dimmer module for a relay module pays for itself.
- Troubleshooting is localized to a single, known vendor.
LEDs-leave on or turn off?
Hey all, We are just getting our first set or LED wash fixtures in our plot. Martin Rush Par 2 Zoom. I have surge protection on each circuit, but no simple way to turn them off at the end of the night. we looked into the ETC relays, but can't swing the cash after the layout for the Martins...
www.controlbooth.com
The ETC CC modules do have switch rated breakers. We've been using them for years to power out LED rig.
Les
Well-Known Member
Two points to consider:
- The PSU's in LED fixtures shouldn't be left "idling" indefinitely if you want to get the maximum lifespan out of them. Especially if they have internal fans. But either way, I prefer things to be "off-off" when not in use.
- My time is better spent not making sure breakers are on when needed and off when not needed. Nor do I trust (or want) volunteers, sometimes young, in an electrical room flipping the correct set of breakers. Also reduces those "nothing's working" phone calls.
Anecdote: Our wireless mic rack is now on the sequencer with the rest of the sound system, but it wasn't always that way. More than once I witnessed a flustered sound technician knee-deep in sound check troubleshooting mics that weren't powered on.
Relays incorporated in to the DMX run of a system can be programmed to turn on with the console and kill power when the console is switched off. This makes for a seamless, convenient, and largely idiot-proof system with little-to-no learning curve.
- The PSU's in LED fixtures shouldn't be left "idling" indefinitely if you want to get the maximum lifespan out of them. Especially if they have internal fans. But either way, I prefer things to be "off-off" when not in use.
- My time is better spent not making sure breakers are on when needed and off when not needed. Nor do I trust (or want) volunteers, sometimes young, in an electrical room flipping the correct set of breakers. Also reduces those "nothing's working" phone calls.
Anecdote: Our wireless mic rack is now on the sequencer with the rest of the sound system, but it wasn't always that way. More than once I witnessed a flustered sound technician knee-deep in sound check troubleshooting mics that weren't powered on.
Relays incorporated in to the DMX run of a system can be programmed to turn on with the console and kill power when the console is switched off. This makes for a seamless, convenient, and largely idiot-proof system with little-to-no learning curve.
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Relays are twice as expensive and our dimmer rack is very accessible. For me, being the only employee in our venue that deals with them it made sense. If the situation were different or we had a bigger budget, relays would 100% be the way to go.
Aaron Clarke
Well-Known Member
I feel the summary here is when you have an existing dimming system that has swappable or easily convertible (in a rated and certified manner) its far more desirable, and most importantly, the most cost effective to use that solution then rip it out and replace it with some other relay system.
That said, I read that in Radio's situation is there is no value in the existing system (not easily converted) so how could you so this from scratch.
I'd ask "what do you consider a theatrical relay system?" If it just defined as something that can be turned on/off via DMX? If so I would say there any many options to make this happen without a full blown ETC level system dependning just how many circuits you need. If just having a master switch somewhere is all you need, this is done in commercial work all the time and can probably be done by most commercial contractors.
That said, I read that in Radio's situation is there is no value in the existing system (not easily converted) so how could you so this from scratch.
I'd ask "what do you consider a theatrical relay system?" If it just defined as something that can be turned on/off via DMX? If so I would say there any many options to make this happen without a full blown ETC level system dependning just how many circuits you need. If just having a master switch somewhere is all you need, this is done in commercial work all the time and can probably be done by most commercial contractors.
This is an important point. Most commercial buildings now have Lighting Control Panels (LCP's), that are just relay panels for lighting loads. I haven't gone through the spec sheets to compare side by side, but there's likely very little advantage in getting the ETC brand name on the relay panel versus the LCP's from a few dozen other manufacturers. There are tons of companies making relay panels and few tangible differences between them. Distinctions between them, if I were to guess, might be whether you can load the circuits up to 100% or not, and being able to keep all of your technical support with the same installer and manufacturer. But so long as you can communicate with these panels over DMX or another protocol, it's debatable how much value ETC's brand name has for panelboards that no one will look twice at until they're replaced in 30-40 years.
So you can look at this two ways:
1) Do you need relay control for modern LED systems, versus leaving these circuits energized 24/7?
2) If the answer above is "Yes", do you subsequently need a relay panel specifically made by a theater lighting manufacturer.
In my mind, the answer to #1 -- it generally protects your investment, reducing the energized time of power supplies and reducing dust intake on fixtures with fan cooling. Will your system blow up in a blaze of glory if you don't have it though? No, but you may end up having to replace/repair fixtures sooner -- and you'll need to give a lot of cleaning love to any fixtures with fan cooling, provided those fans are not thermostatically controlled to only engage when the fixture is actually in use.
As for #2 -- no, there is little compelling reason for the relay panel to be theater-specific beyond that it's easier to specify and deal with for any potential support issues. If you're getting a system from someone like Eaton, your theatrical vendor may not have a support relationship with them -- but your average electrician is far more likely to know what they're walking up to -- so there is a tradeoff. The controller may not natively support DMX but there will certainly be a widget available that can interface it. Since modern buildings have LCP's building or campus-wide, integration with a broader lighting control system may also be just a little bit easier. Personally I don't know where the pricing falls if there's any compelling reason to go one way or the other, but certainly it is not like ETC is the only company making relay panelboards.
Footnote: Most of my work is new construction so I mostly care about relay panelboards -- not dimmer racks with relay or ThruPower modules. I would not specify an actual dimming rack with relay or ThruPower modules in this day and age unless it was a professional roadhouse that had a greater risk of encountering tungsten fixtures.
jmabray
Active Member
I am going to argue this point a little bit. Most of your other "Lighting relay panels" (Wattstopper, Hubbell, nLight, etc) have a few distinctions from an ETC panel.
They are typically only relays. Meaning you still have to have circuit breaker protection provided separately. Those circuit breakers are usually not fully loadable to 20 amps like theatrical panels are.
Most (*Not all*) theatrical relay panels are able to be main lug fed, have integral circuit breakers, and those circuit breakers are fully loadable to 20 amps.
Craig Hauber
Well-Known Member
As a part time commercial electrician installing tons of high-bay LED units in the warehouses and pole barns that seem most prevalent in our corner of the nowhere. Just have your electrician install lighting contactors. They are a readily available item at any supply house and something local electricians know well without them having to go outside of their comfort zone to source (like most "theater specific" vendors can be sometimes)
The contactors can be powered by a standard light switch or a nice locking key switch in the booth (or wired 3-way with multiple switches) Status indicators can be easily added too so there's a "system-on" warning light near the last door normally exited from.
This is of course assuming that you are wiring new circuits in the ceiling. If your dealing with existing, have your same electrician install switch duty rated breakers in the panel -or add a sub-panel just for this purpose.
One other reason I've had to use contactors is that some of these new buildings that farmers are investing in up here are 150'x300' with 25'to 35' ceilings and wire run lengths are too long for normal 3 and 4 way switches. You can easily get up to 500' on the travelers alone with the switch-leg adding another 200'. You can run that type of lengths if all your doing is switching the contactors
Another aspect of commercial lighting is that they are also 0-10v capable. When wired in that manner it means that the fixtures are always powered and have live electronics their entire lifespan. So if theatrical lighting vendors are building their units to that kind of spec it shouldn't matter if they are left on all the time. Unfortunately almost all of them I've encountered have fans and I haven't seen any yet that idle those fans down when not needed. So fan lifespan is a concern as well as it always sucking air through the units even in those times when onstage things are being built or the house cleaned (more dust). I've seen such fans plugged solid and dead in nightclub installations long before they would have died from normal clean use.
We went for a Z88/Eaton Rig Switch. 12 (or 24 also available) DMX addressable contactors, with individual RCBO protection but with the intelligence built in that if you try to slam all 12 or 24 addresses from off to on at the same time, the controller will sequence them so as to avoid a huge inrush surge.
In my venue we have ETC everything. I prefer the Relay cards over the CC cards because I can turn them on and off from the console. I patch all my relays into a channel or 4. and my start up macro puts a hot patch curve on that channel. (I personally don't like the park method) and then my shut down macro takes the curve off that channel. Since we also have ETC Lustrs that's wonderful because you don't need to swap to a relay card, just put the dimmer in "Switched" and apply the same hot patch curve. A relay is better though, because it elliminates the possibility of powering that LED not in switched mode.
In the end, if you have dimmers that can be swapped for Relays, I would suggest that method. Like others have said, I personally don't like having to walk all over my building to switch off breakers or unplug cables. And I don't like leaving my gear on 24/7.
In the end, if you have dimmers that can be swapped for Relays, I would suggest that method. Like others have said, I personally don't like having to walk all over my building to switch off breakers or unplug cables. And I don't like leaving my gear on 24/7.
Unfortunately, the dimmer system I'm working with does not allow me to switch in Relay Modules for Dimmer Modules. That would mean installing different dimmer system to accommodate accepting Relays, which seems much less cost effective. Though it looks like I can use the Test buttons on the dimmer packs to lock on full power to dimmer and patch the appropriate circuits for the LEDs to the full on dimmers.
I'll join in with RickR... don't do this.
I cannot recall the manufacturer, but the DMX breaker panels at our facility have what is know as a motorized circuit breaker. OCPD is built in to each circuit, with the control head responding to the DMX for on/off. I have seen ETC Echo panels which have a relay in the bottom of the rack and a breaker above.
Ben Stiegler
Well-Known Member
Another approach is to use an industrial contactor controller - where a single 110V coil throws some nice heavy duty relay contacts that can each switch say 30A of 110. I have these (Cutler Hammer I believe) in an outdoor facility to handle yard and underwater lighting which used to be incandescent, then halogen ... before going LED. Its easy to have a master switch throw all that power on/off at once. This is installed near the breaker panel. In fact, we use a Torq ELC374 4 channel astro-clock software-driven timer switch to ensure no one leaves things on past a certain wee hour - and it has nice dry contacts that can also be programmed as a toggle on/off. You probably don't need the Torq. Here's a 40A x 3 pole unit for under $100 - plus you'll need a NEMA enclosure for it. So - not a huge investment. https://www.supplyhouse.com/Eaton-C...Ay4UmXWGOuxu0VmZtK-tt_uf0CMHhmF8aAhNeEALw_wcB
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