Are Theatrical Relays Really Necessary In LED Based Systems

[RonHebbard]

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.

Quoting you: "I cannot recall the manufacturer, but the DMX breaker panels at our facility have what is known as a motorized circuit breaker". Lyntec perhaps?
Toodleoo!
Ron Hebbard

 

[SteveB]

Quoting you: "I cannot recall the manufacturer, but the DMX breaker panels at our facility have what is known as a motorized circuit breaker". Lyntec perhaps?
Toodleoo!
Ron Hebbard

I think that might be correct. I sure I have some documention or maybe posted the name, but being recently retired am too lazy to go look it up.

 

[Radio]

Most of the sequencing relay systems I'm finding out there are gross overkill for my theatre's needs. Right now I'm trying to determine if a Furman ASD-120 2.0 will give me what I need in the short term to run a mixed rig. This would give me six 20A channels with sequenced start-up and a master power switch. This unit looks to be easily integrated into my current system with minimal need for an electrician.

 

[Malabaristo]

Most of the sequencing relay systems I'm finding out there are gross overkill for my theatre's needs. Right now I'm trying to determine if a Furman ASD-120 2.0 will give me what I need in the short term to run a mixed rig. This would give me six 20A channels with sequenced start-up and a master power switch. This unit looks to be easily integrated into my current system with minimal need for an electrician.

Are you running portable cables to everything from the Furman, or were you planning to use male pigtails that transition into building wiring? Generally the latter is not allowed by code unless it meets the requirements of NEC 520.50 for a Roadshow Connection Panel. One key feature is that each circuit needs a permanent overcurrent protection device (circuit breaker or fuse) to protect the building wiring. Breakers in the Furman don't count because that's a portable device. Such panels are generally custom and correspondingly expensive.

 

[STEVETERRY]

Are you running portable cables to everything from the Furman, or were you planning to use male pigtails that transition into building wiring? Generally the latter is not allowed by code unless it meets the requirements of NEC 520.50 for a Roadshow Connection Panel. One key feature is that each circuit needs a permanent overcurrent protection device (circuit breaker or fuse) to protect the building wiring. Breakers in the Furman don't count because that's a portable device. Such panels are generally custom and correspondingly expensive.

Exactamundo.

ST

 

[Radio]

Are you running portable cables to everything from the Furman, or were you planning to use male pigtails that transition into building wiring? Generally the latter is not allowed by code unless it meets the requirements of NEC 520.50 for a Roadshow Connection Panel. One key feature is that each circuit needs a permanent overcurrent protection device (circuit breaker or fuse) to protect the building wiring. Breakers in the Furman don't count because that's a portable device. Such panels are generally custom and correspondingly expensive.

The Furman unit would replace one of my dimmer packs and be connected to my standard patch bay(spider patch) to six of the former patch points.

 

[jmabray]

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.

ETC has Sensor IQ panels that do this...

 

[Ravenbar]

The difference between relay modules and dimmer modules is the waveform of the AC the fixture sees. Supposedly that makes I difference, but I've yet to see one.

I work with a system(ETC) with relay modules for all the LED lights. I've long parked dimmers at 100% as a way to power the cheap DJ/cheap lights we use for effects and the like with no problem. I'd expect the cheap lights to be picklier about their power source than quality fixtures.

 

[Aaron S.]

The difference between relay modules and dimmer modules is the waveform of the AC the fixture sees. Supposedly that makes I difference, but I've yet to see one.

I work with a system(ETC) with relay modules for all the LED lights. I've long parked dimmers at 100% as a way to power the cheap DJ/cheap lights we use for effects and the like with no problem. I'd expect the cheap lights to be picklier about their power source than quality fixtures.

So you are powering all your LED's from Relay modules?

 

[121 Gigawatts]

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..

A little late to the game but... true that most circuit breakers cannot- based on the NEC... be used for switches on the regular but, breakers labeled SWD are. Those would be installed in large and small shopping centers and schools without automation or wall switches.

From: https://www.c3controls.com/white-paper/circuit-breaker-vs-switch/

"Circuit breakers can be rated for switching duty for lighting circuits. Circuit breakers applied in 120V or 277V fluorescent lighting circuits must be marked SWD or HID. SWD stands for Switching Duty. HID signifies rated for High Intensity Discharge lighting. The UL489 Standard for MCBs states that an SWD circuit breaker can be rated up to 20A, no more. HID breakers are rated up to 50A."

 

[Ravenbar]

So you are powering all your LED's from Relay modules?

Yes, other than the occassional "el-cheapo" type fixture I some years use for special/effects lighting, in which case I simple park a dimmer at full and call it good enough. i.e. a couple cheap($40/es) pars I used for the last show to similate the 2 actors sitting in front of a TV before the lights came up on that scene. I consider such lights to essentially be disposable, so any damage from a less than clean power source isn't much of a concern.

On the topic of the waveform, dimmers operate by modifying the duty cycle of the waveform, i.e. making the waveform a square wave and controlling the length of on and off pulses allowed through. A 1:1 ratio would equal full power, while 1:2 would be 50%. This is essentially how switch mode power supplies work.

 

[Aaron S.]

Yes, other than the occassional "el-cheapo" type fixture I some years use for special/effects lighting, in which case I simple park a dimmer at full and call it good enough. i.e. a couple cheap($40/es) pars I used for the last show to similate the 2 actors sitting in front of a TV before the lights came up on that scene. I consider such lights to essentially be disposable, so any damage from a less than clean power source isn't much of a concern.

On the topic of the waveform, dimmers operate by modifying the duty cycle of the waveform, i.e. making the waveform a square wave and controlling the length of on and off pulses allowed through. A 1:1 ratio would equal full power, while 1:2 would be 50%. This is essentially how switch mode power supplies work.

Understood, just from your initial comment, I thought you were saying you use the relay cards for the cheapo LEDs and haven't seen an issue,

Thanks for the clarification.

 

[Ravenbar]

Understood, just from your initial comment, I thought you were saying you use the relay cards for the cheapo LEDs and haven't seen an issue,

Thanks for the clarification.

The bulk of ourt system was changed over to decent quality LED fixtures a couple years ago. All those are on relay power,m with the relay powered circuits being equiped with edison receptacles, and the dimmers with stagepin.

I insisted on keeping the usage of the older fixtures, to the point tje installers left as many fixtures in the air as they could, totally missing my long term mentality, wheras I can repair the older fixtures, but the LED fixtures would need to be sent in for repair,, and hopefully the parts are available to keep them going. We're already seeing lights going down, after less than 2 school years.

 

[Aaron S.]

The bulk of ourt system was changed over to decent quality LED fixtures a couple years ago. All those are on relay power,m with the relay powered circuits being equiped with edison receptacles, and the dimmers with stagepin.

I insisted on keeping the usage of the older fixtures, to the point tje installers left as many fixtures in the air as they could, totally missing my long term mentality, wheras I can repair the older fixtures, but the LED fixtures would need to be sent in for repair,, and hopefully the parts are available to keep them going. We're already seeing lights going down, after less than 2 school years.

Oh so you don't swap relay cards around your dimmer racks depending on where the intelligent fixtures are?

Do you find that you need to run cable all through your building depending on where a fixture ends up?

 

[RickR]

On the topic of waveform: remember that most dimmers regulate the maximum voltage. (ie. 115 even if incoming is 125) This too is done by duty cycle but doesn't go away if the dimmer is "full"!

 

[macsound]

Based on reading other comments, using circuit breakers isn't the recommended way to power off circuits - but - I've worked in many venues where this was the norm. And in most of these places, it lasted for a dozen years before the next remodel introduced something else.
Also - I've worked in many venues - mainly corporate and churches - where equipment was on 24/7. Dimmers, audio amps, powered speakers, signal processors, etc. None of them had any noticeable shortened lifespan, and anecdotally, in the years I worked in those places, none ever failed. One notable hotel had probably 200 power amps and 1000 LED pars and while they weren't always in operation, they were always electrified, waiting for a wall panel to trigger them.
Not trying to start anything, just reporting my historical experience as a designer in spaces.

 

[Aaron S.]

Based on reading other comments, using circuit breakers isn't the recommended way to power off circuits - but - I've worked in many venues where this was the norm. And in most of these places, it lasted for a dozen years before the next remodel introduced something else.
Also - I've worked in many venues - mainly corporate and churches - where equipment was on 24/7. Dimmers, audio amps, powered speakers, signal processors, etc. None of them had any noticeable shortened lifespan, and anecdotally, in the years I worked in those places, none ever failed. One notable hotel had probably 200 power amps and 1000 LED pars and while they weren't always in operation, they were always electrified, waiting for a wall panel to trigger them.
Not trying to start anything, just reporting my historical experience as a designer in spaces.

In my opinion, just because it works doesn't make it the best way to do it. Sure, that standard breaker will work for years probably, flipping it on and off every night. But, it isn't recommended because they aren't made to do that.

I can plug an LED fixture into a dimmer rack and park the dimmer at full. Sure, it will turn on and work, but it isn't the right way to do it.

I lean towards the relay cards because I have control of all my gear from my console. I don't have to walk around to 5 different breaker panels and flip on 7 breakers at each panel.

With all that being sad, every venue and every company is different. What is more logical, be it cost or time, at one venue might not be the optimal solution at another.

 

[macsound]

In my opinion, just because it works doesn't make it the best way to do it. Sure, that standard breaker will work for years probably, flipping it on and off every night. But, it isn't recommended because they aren't made to do that.

I can plug an LED fixture into a dimmer rack and park the dimmer at full. Sure, it will turn on and work, but it isn't the right way to do it.

I lean towards the relay cards because I have control of all my gear from my console. I don't have to walk around to 5 different breaker panels and flip on 7 breakers at each panel.

With all that being sad, every venue and every company is different. What is more logical, be it cost or time, at one venue might not be the optimal solution at another.

I think my actual opinion on it is that it’s a grey area. While I didn’t think it was the best solution to use breakers as daily or weekly switches, I also knew it was an easier replacement and better as an option than, say, using a dimmer as a relay. And if at some point it failed, it would be a good excuse to replace it with something purpose designed.

 

[Aaron S.]

I think my actual opinion on it is that it’s a grey area. While I didn’t think it was the best solution to use breakers as daily or weekly switches, I also knew it was an easier replacement and better as an option than, say, using a dimmer as a relay. And if at some point it failed, it would be a good excuse to replace it with something purpose designed.

Agreed. It’s better than using a dimmer to power an LED fixture. And in your situation it was the better option.

Like I said, each situation is different. Replacing a $50 breaker every year over the course of 25 years will be more cost effective for some venues than buying a single relay card to solve the problem.

I use relays at my venue, and the company will spend the additional money on the relays because of the controllability and my preference.

 

[Malabaristo]

You also have to evaluate the cost of failure. If that breaker that wasn't designed for switching duty does fail, it's probably going to fail to turn on. At that point you're either going without whatever it powers, or making an emergency electrician hire to swap it out--possibly after hours and on a weekend...

I've never used one to failure, so I can't say for sure whether it would gradually become intermittent and give you a little warning that it's on the verge, or if one day it just won't latch on without much warning.