How much Electric Needed to run entire Lee Colortran 96 Dimmer Rack

JimP0771

Well-Known Member
Hi all

I am sorry to bother here again. My theate only uses about 12 dimmers consisting of 6 dimmers mods of our entire Lee Colortran ENR 66 dimmer rack. This has to do with power restraints coming in to the building. The first lighting system that was there was a Spectrum Design and Development what ever company that is system that consisted of 2 dimmer packs that had 6 dimmers each and were in a road case that was wired directly to the power source coming in. When that system died totally we bought and instald the ENR 66 dimmer rack that we got from my local High school when they were renovating the auditorium. The electrician we got to install the ENR 96 told us any more than 12 dimmers could cause a fire so that is all we had installed.

My question is does any one here know how much power would be needed to add more dimmers to the ENR 96 system to at some point in the future be able to add more lights to the grid? We most like most like will not be doing this any time soon but I thought it would be good to know just incase we decided we wanted to install more in the future.

Thanks
 
The load is largely dependent on what you're plugging into the dimmer. You'll get a lot more Source Fours at 575W then you will with older generation lekos burning a 1000W FEL.

What's the capacity of the service feeding the dimmer rack? Is it three phase?

I'm willing to bet the electrician is on to something, though if he didn't put any kind of fuse or breaker protecting the feed to the dimmer, you've got other problems.
 
The load is largely dependent on what you're plugging into the dimmer. You'll get a lot more Source Fours at 575W then you will with older generation lekos burning a 1000W FEL.

What's the capacity of the service feeding the dimmer rack? Is it three phase?

I'm willing to bet the electrician is on to something, though if he didn't put any kind of fuse or breaker protecting the feed to the dimmer, you've got other problems.

No we have pertection there are fuses that are protection the Rack definitely. First thing we did From what the oner has told me it is 3 Phase 240 running the system. Now I do not want to be the one to find out. So the load ad capacity has to do with how many lights you are putting on the system?
 
Also has anyone herd of Spectrum Design and Development. I can not find anything on them as and Lighting company?
 
Hi all

I am sorry to bother here again. My theate only uses about 12 dimmers consisting of 6 dimmers mods of our entire Lee Colortran ENR 66 dimmer rack. This has to do with power restraints coming in to the building. The first lighting system that was there was a Spectrum Design and Development what ever company that is system that consisted of 2 dimmer packs that had 6 dimmers each and were in a road case that was wired directly to the power source coming in. When that system died totally we bought and instald the ENR 66 dimmer rack that we got from my local High school when they were renovating the auditorium. The electrician we got to install the ENR 96 told us any more than 12 dimmers could cause a fire so that is all we had installed.

My question is does any one here know how much power would be needed to add more dimmers to the ENR 96 system to at some point in the future be able to add more lights to the grid? We most like most like will not be doing this any time soon but I thought it would be good to know just incase we decided we wanted to install more in the future.

Thanks
@JimP0771 "Bother us ANYTIME that's what we're here for, we thrive on being bothered, especially by "botherers" who type in complete sentences, know where the 'shift' key's located, how to use it, and DO.

Normally when dimmer tacks are installed, electrical engineers specify electrical feeds capable of powering the entire rack to its full capacity; it would be EXTREMELY unusual to install a 48 slot / 96 dimmer rack and only provide input power for the quantity of dimmers initially installed including their typical loads at the time of installation.

Stepping back and looking at this as if your venue was being constructed anew:
Typically a 48 slot / 96 dimmer rack would be sourced from 3 phase power.
96 dimmers = 32 dimmers per phase.
32 dimmers at nominally 20 amps per dimmer would equate to 640 amps per phase.
(Based upon your being in North America, not the UK where your voltage would normally be much higher)

Up here north of Donnie's walls, I'll cite two installations (within the same complex) spec'd by two different P. Eng's.

One powered a Strand CD80 rack with 3 phase 800 Amps, his logic: 640 per phase x the 125% allowance normally decreed for motors and their starting / inrush currents in industrial applications.

Another identical rack in the same venue was added years later by a second Electrical P. Eng. The second P. Eng's background was not entirely powering large industrial motors. The second P. Eng realized all the loads were purely resistive incandescent lamps; he also realized it would be virtually unheard of for all 96 dimmers to be fully loaded during any one production:
This second Electrical P. Eng looked at the rack as being similar to powering a high-rise apartment tower or typical city residential street.
He applied loading logic as per our code book realizing not all homeowners will run their ovens at the same instant nor will they all use their electric kettles, toasters or heating pads at the same instant.
This P. Eng specified a 3 phase 400 amp breaker to power this additional rack.

Two identical racks; different theatres within the same building: One rack supplied with 3 phase 800 amps the other with 3 phase 400 amps.
During my time as an IA assistant LX in the main stage venue (1973 through 1977) I was never aware of either rack ever tripping its main breaker.

If you want to carry this one step further: The larger venue opened with 5 similar racks (from a different manufacturer) in its basement dimmer room.
Each rack housed 20 x 6 Kw dimmers for a total of 100 6Kw dimmers: The entire five racks were sourced by a 3 phase 1200 amp motor actuated breaker.

What's "typical"? I rest my case. @TimMc and / or @Ron Foley care to comment??
Toodleoo!
Ron Hebbard
 
Last edited:
I'm willing to bet the electrician is on to something, though if he didn't put any kind of fuse or breaker protecting the feed to the dimmer, you've got other problems.

I'm not! Regular electricians very often have no idea how theatre works, and I've had to explain to more than a few the difference between nameplate ratings and the actual load that's likely to be connected. He might have meant that the total capacity is 12*20A, but that doesn't mean you couldn't do 24*10A or any other combination. The fact that he said "Could start a fire" rather than "Could trip a breaker" is kind of a red flag to me, but he may have just been using hyperbole to instill caution. If he was serious, then he did something very wrong with the system.

@JimP0771 Do you know what circuit breaker feeds the dimmer rack? If so, what does the label on the breaker say? (Pictures are always good...) "3 Phase 240 " is another odd thing to say. In the US, 3-phase power is usually 120/208VAC. 120/240VAC would mean bi-phase (often referred to as "single-phase", but it's really two hots, neutral, & ground).
 
Normally when dimmer tacks are installed, electrical engineers specify electrical feeds capable of powering the entire rack to its full capacity;

Not in my experience in US because in a theatre situation that never happens. I provide a load schedule - last time I did dimmers it was 1150 (2 units at 575) watts per dimmer which is a little over 300 amps (120/208) per 96 dimmer rack - so suggest 400 amps. more ofetn I'll ask for 800 or 1000 for 2 or 3 racks bussed. Full load would be 640 amps and with possible derating 800 amps per rack - a waste of money with current equipment. Consider 800 amps is what 500 Source4s with 575s need - at FULL. A lot of theatres there is not sufficient battens installed to hang that many fixtures. (Consider 3 FOH pipes @ 80', 4 electrics at 60', and 2 box booms and 8 on stage booms at 20' - thats around 690' or 460 units on 18" centers - all at FULL. Do you have the labor to hang and focus 500 units?) Obviously smaller systems may be more heavily loaded per circuit, which is why NEC wants a load schedule.

So ask yourself - how many units are you likely to ever hang at what wattage and do the math. Same great white paper at ETCconnect by Steve Terry on this.
[Edit by Mod.: Link to paper at https://www.controlbooth.com/threads/dimmer-feeds-how-much-power-is-enough.9014/ ]


Anecdotally, in a renovation at UNM, told we could not change existing 320 amp feed. Put in 2+racks of CD80s. School hung the max inventory available - 130 or 150 units in a modest black box. Main breaker tripped after 35 minutes of all at full.

Yale Rep functioned with 400 amps for entire building for many years. Only when they added an elevator for ADA did they have trouble and mounted an ammeter for the operator, who was warned when elevator was going to be used and could watch the ammeter and pull back on the grand master (in those days).

So you have some calculations to do which folks here will help you with.
 
Last edited by a moderator:
Not in my experience in US because in a theatre situation that never happens. I provide a load schedule - last time I did dimmers it was 1150 (2 units at 575) watts per dimmer which is a little over 300 amps (120/208) per 96 dimmer rack - so suggest 400 amps. more ofetn I'll ask for 800 or 1000 for 2 or 3 racks bussed. Full load would be 640 amps and with possible derating 800 amps per rack - a waste of money with current equipment. Consider 800 amps is what 500 Source4s with 575s need - at FULL. A lot of theatres there is not sufficient battens installed to hang that many fixtures. (Consider 3 FOH pipes @ 80', 4 electrics at 60', and 2 box booms and 8 on stage booms at 20' - thats around 690' or 460 units on 18" centers - all at FULL. Do you have the labor to hang and focus 500 units?) Obviously smaller systems may be more heavily loaded per circuit, which is why NEC wants a load schedule.

So ask yourself - how many units are you likely to ever hang at what wattage and do the math. Same great white paper at ETCconnect by Steve Terry on this.

Anecdotally, in a renovation at UNM, told we could not change existing 320 amp feed. Put in 2+racks of CD80s. School hung the max inventory available - 130 or 150 units in a modest black box. Main breaker tripped after 35 minutes of all at full.

Yale Rep functioned with 400 amps for entire building for many years. Only when they added an elevator for ADA did they have trouble and mounted an ammeter for the operator, who was warned when elevator was going to be used and could watch the ammeter and pull back on the grand master (in those days).

So you have some calculations to do which folks here will help you with.
@JimP0771 With my apologies; mia culpa, mia maxima culpa (and I'm not even Catholic).
I erred when I posted: "Normally when dimmer tacks are installed, electrical engineers specify electrical feeds capable of powering the entire rack to its full capacity;" Permit me to restate: Normally up here north of Donnie's walls, electrical consulting PEng's routinely specify 400 amp 3 phase 120 / 208 volt services for 48 Slot / 96 Dimmer racks along with 200 amp 3 phase 120 208 volt sources for 1/2 size 24 Slot / 48 Dimmer racks.

Routinely House and Emergency lighting would be sourced from separate racks and services, racks and services NOT also powering performance lighting.

Furthermore, theatrical consultants drawings and specifications would be scrutinized by various P. Engs in all relevant fields prior to being stamped and approved for bidding and construction. Various consultants, P Eng's, Inspectors and contractors often have differing interpretations and opinions as I noted in my post #5 up thread.
I'll crawl back in my cave now.
Toodleoo!
Ron Hebbard
 
Also has anyone herd of Spectrum Design and Development. I can not find anything on them as and Lighting company?
They were a second/third tier manufacturer of dimmers and controls in the 1970s/80s, roughly equivalent to Leprecon or Lightronics of today. IIRC in addition to the stage, they made or imported a lot of disco lighting.


Could these be your original dimmer packs?
proxy.php
 
They were a second/third tier manufacturer of dimmers and controls in the 1970s/80s, roughly equivalent to Leprecon or Lightronics of today. IIRC in addition to the stage, they made or imported a lot of disco lighting.


Could these be your original dimmer packs?

That is exactly them however. Ours were stage pin and not edition. That is so cool that I see others that exist. I have always wondered about this company. Also Years ago when ours were having issues I wanted to call the company to see if they could give me any advice on repairs after doing a hard and long search on the Internet I finally found a phone number that was stated that it was for the Spectrum Design and development company. When I called the number I spoke to a very nice lady and explained my situation. She said that number is now for a company that makes things like table and floor lamps and they have not produced Stage lighting equipment for years. She also explained to me that unfortunately no one from the old Spectrum Design and Development company still worked there except for her. So that was where I got with our system. That was shortly before that system totally died on us and we got the Lee Colortran ENR 96 Installed in its place


Also did you know you could control the dimming of the lights one and off basically with a 9 volt battery I tried it when we had ours installed.
 
Last edited by a moderator:
Also did you know you could control the dimming of the lights one and off basically with a 9 volt battery I tried it when we had ours installed.

Yup, early electronic dimmers were remotely controlled by DC voltage. 10V was/is the most common but others were used. 0-10V is still quite common in architectural dimming. Our wiki has some info if you're curious.
 
Also did you know you could control the dimming of the lights one and off basically with a 9 volt battery I tried it when we had ours installed.
Hence the famous (and now even somewhat dated) quote:
"You used to be able to trouble-shoot a lighting system with a 9-volt battery. Today you need a laptop and an FTP site."
What's an FTP site? Just text me the config files.;)
 
They were a second/third tier manufacturer of dimmers and controls in the 1970s/80s, roughly equivalent to Leprecon or Lightronics of today. IIRC in addition to the stage, they made or imported a lot of disco lighting.


Could these be your original dimmer packs?
proxy.php

This reminds me of the old LMI dimmers at a production company I worked for back in the day had. They were so old we ran analog signal to them through a mess of cinch jones connectors from an old Express console. Half way through every show it seemed we'd lose connection and have to radio the monitor engineer to run over and wiggle the connectors....LMAO
 
I'm not! Regular electricians very often have no idea how theatre works, and I've had to explain to more than a few the difference between nameplate ratings and the actual load that's likely to be connected. He might have meant that the total capacity is 12*20A, but that doesn't mean you couldn't do 24*10A or any other combination. The fact that he said "Could start a fire" rather than "Could trip a breaker" is kind of a red flag to me, but he may have just been using hyperbole to instill caution. If he was serious, then he did something very wrong with the system.

@JimP0771 Do you know what circuit breaker feeds the dimmer rack? If so, what does the label on the breaker say? (Pictures are always good...) "3 Phase 240 " is another odd thing to say. In the US, 3-phase power is usually 120/208VAC. 120/240VAC would mean bi-phase (often referred to as "single-phase", but it's really two hots, neutral, & ground).

I wanted to put everyone's minds to rest here and say yes we do have a main breaker that is hooked to the entire lighting power feed that comes into building for our lighting system and one that is right near the lighting dimmer rack itself. I know cause I have had to shut off the Main breaker in the past when I do any sort of servicing of the system even if it is to pull out the dimmers to vacuum and clean out the system the main breaker goes off. I am scared Sh**less if electricity and what it can do to you. People tell me I am crazy and I should just turn off the breaker next to the dimmer rack but I tell them you never know when someone could come by and say what is this switch do and accidently turn it on and you have one fried person. So Main breaker in basement of building goes off whenever the system gets serviced. In doing so one time I accidently also hit the main breaker for the entire building and left everyone in the dark . I never told them that is what happened Just quickly turned the power back on and said it must have been a power flicker
 
Last edited:
Oh Know I know that and we have that as well. But we still turn the main breaker off for extra safety. You can never be to safe. I am afraid of electricity. Been chocked by electricity at hone once but not to bad. Just think what that higher powered would do. Don't wanna even think of it.
 
Oh Know I know that and we have that as well. But we still turn the main breaker off for extra safety. You can never be to safe. I am afraid of electricity. Been chocked by electricity at hone once but not to bad. Just think what that higher powered would do. Don't wanna even think of it.

The voltages in the lighting cabinet are exactly the same as the voltages at your house, so it would be the same shock potential for you. It's still plenty, of course, more than sufficient to be deadly if things go the wrong way; but a 120V 600A circuit is just as dangerous from an electrocution point of view as a 120V 15A circuit.

(Note I didn't say just as dangerous overall; a misplaced wrench or screwdriver would be far more worrysome on the higher current circuit and more likely to cause a fire or other spectacular display of electrical prowess. But for getting shocked, the limiting factor is the resistance of your body, which holds the currents down to pretty low levels comparatively speaking--and it also doesn't take too many milliamps to interfere with one's heartbeat, and that is pretty important to keep going!)

If you don't have a non-contact voltage testing probe, that's a very handy tool to have around and a good check to ensure that the power is actually turned off both for safety and for peace of mind. They are not all that expensive, either. They're great for finding out which wires are powered, or if an outlet is live, and so forth.
 

Users who are viewing this thread

Back