# Turning 120v into 208v



## lightguywcl (Jul 10, 2013)

I am getting some new moving lights and I would like to get vl 3000's but I need 208v to power them up. I do not want to spend the money on a distro and a bunch of cable. So I was thinking of modifying some of my breakouts and making 3 208v circuits out of them. Has anybody done this and does this sound like a bad idea? I have etc sensor racks and I will be putting ac relay modules in them. I know I have to use hots that are out of phase to get the 208v and I know the breakers will not throw both sides if one side goes and I need to too check if the pin out config will be the same if I move the 208v breakouts around. This is a professional road house and I don't want to feel like I am jury-rigging the place just to make something work. Thank you.


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## techieman33 (Jul 10, 2013)

No, that won't work, it's all kinds of illegal. Suck it up, buy a distro, and do it the right way.


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## lightguywcl (Jul 10, 2013)

I guess I need to buy the nec code book. I am guessing that the problem is not having a double throw breaker. If I can't get 208v economically I can still buy 120v movers not a big deal. Was just looking for more options.


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## Footer (Jul 10, 2013)

Your looking at adding less than 5% of the cost of the lights to the order with a proper distro and L6 cable. 

Sent from my Nexus 7 using Tapatalk HD


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## lightguywcl (Jul 10, 2013)

I have read other posts and I saw a quote that probably applies here. "Just because it works does not mean its right." I am sure it will work but I would like to know why it is not right. For my own education.


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## JD (Jul 10, 2013)

lightguywcl said:


> I have read other posts and I saw a quote that probably applies here. "Just because it works does not mean its right." I am sure it will work but I would like to know why it is not right. For my own education.



Whenever you have two hot legs, you need a common throw breaker so that both legs are cut if there is an error. Also, 208 connectors must be unique when in the same venue as 120 connectors, thus the NEMA designations. Now you may ask about socapex.... many have...


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## lightguywcl (Jul 10, 2013)

Adding 208v power to a $150000.00 lighting package may not be that much in the grand scheme of things but it is not going to be that easy to add a distro. It needs to be a semi permanent installation. Plus other problems that I probably have not thought of yet. I could go into detail but I don't want to bore everybody with the power distribution system in my venue. I am happy to talk about it but I think I would rather get mac vipers instead of running hundreds of feet of cable for 208v.


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## gafftapegreenia (Jul 10, 2013)

lightguywcl said:


> Adding 208v power to a $150000.00 lighting package may not be that much in the grand scheme of things but it is not going to be that easy to add a distro. It needs to be a semi permanent installation. Plus other problems that I probably have not thought of yet. I could go into detail but I don't want to bore everybody with the power distribution system in my venue. I am happy to talk about it but I think I would rather get mac vipers instead of running hundreds of feet of cable for 208v.



By all means, get into it. We love talking about boring power distribution issues (seriously, we do).

Also the Vipers are pretty sweet. We just got two of them to replace the Mac 700's we've rented several times. What kind of throws are you looking it?


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## lightguywcl (Jul 10, 2013)

I knew I needed unique plugs. So the only thing that is keeping this from working is a double throw breaker. Can I take my etc sensor module R20AF connect the two breakers together and make it a double throw?


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## lightguywcl (Jul 10, 2013)

I am a typical road house. With a house plot that I have been developing over the years. I have a 3 color wash with 2 systems of high sides plus specials over 4 electrics plus 60 pars upstage for music acts. There are times that the act wants movers that we rent along with a grand ma. I finally got the money to get a new console and movers so we did not have to rent anymore. 

All my power comes from the grid in the form of socopex on each side of the stage. I could either put the distro on the grid or on the stage right pin rail. Still a long way from a power source. My trims are mostly 22 to 24 ft. The proscenium opening is 30 ft by 60 ft. 80 ft grid. Almost 1800 seat theater. 

The easy way is to get new mac vipers. But as I was looking at used vl 3000's it is almost 2 to 1. I think I would rather have 16 used vl3000's instead of 8 new mac vipers.


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## Footer (Jul 10, 2013)

lightguywcl said:


> I am a typical road house. With a house plot that I have been developing over the years. I have a 3 color wash with 2 systems of high sides plus specials over 4 electrics plus 60 pars upstage for music acts. There are times that the act wants movers that we rent along with a grand ma. I finally got the money to get a new console and movers so we did not have to rent anymore.
> 
> All my power comes from the grid in the form of socopex on each side of the stage. I could either put the distro on the grid or on the stage right pin rail. Still a long way from a power source. My trims are mostly 22 to 24 ft. The proscenium opening is 30 ft by 60 ft. 80 ft grid. Almost 1800 seat theater.
> 
> The easy way is to get new mac vipers. But as I was looking at used vl 3000's it is almost 2 to 1. I think I would rather have 16 used vl3000's instead of 8 new mac vipers.



Etc does not make a 208 module to my knowledge. You can not just tie the breakers together, that would void Ul and be illegal in so many other ways. You would also have to build cheaters which are also illegal to use the power. 

How do you intend to get the power to the units if you go 120? Your already picking cable to the electrics so we what's another cable. 

Sent from my Nexus 7 using Tapatalk HD


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## lightguywcl (Jul 10, 2013)

They will most likely go on my house electrics but I am not sure so I would like to be flexible with power. So I just switch my dimmer module to a relay module. Holy crap this is hard. Ok how about a certified 20amp double throw breaker in the junction box between the socopex and the dimmer rack. I could make it 15 amp to be on the safe side. This reminds me of Mythbusters. Trying to find a way it could possibly work. I think I need to call the applications engineer at etc so they can make me double throw breakers.


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## jhochb (Jul 10, 2013)

lightguywcl said:


> I guess I need to buy the nec code book. I am guessing that the problem is not having a double throw breaker. If I can't get 208v economically I can still buy 120v movers not a big deal. Was just looking for more options.




Good Morning Lightguywcl

Both breakers in an ETC module gets it’s power from the same phase so bridging them wom’t get you anything. You’d have to jump several modules to get to another phase.

BTW
I tried to get my boss to buy me the 2014 NEC book, he told me the state of FL just adopted the 2011 code.


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## lightguywcl (Jul 10, 2013)

I knew I needed to check that. I should have probably have done that before I started talking about stuff I could not possibly do. One of the future upgrades is to change the back plates on the dimmers to accept the new ecm's. Maybe they could change a few wires around for me. So how many mac vipers can I get for $100000.00 dollars?


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## gafftapegreenia (Jul 10, 2013)

lightguywcl said:


> So how many mac vipers can I get for $100000.00 dollars?



Ten .


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## lightguywcl (Jul 10, 2013)

That is what I thought. I will probably go with 8 and add some auras or 301's.


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## DuckJordan (Jul 10, 2013)

It's not that easy the modules pull power from rails and do you really want two circuits on one electric ending up on opposite sides of the rack for breakers? Idk but to me its a waste of time and energy. Throw a distro on the grid, run feeder to it, call it a day by dropping soco where you need it.


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## lightguywcl (Jul 10, 2013)

I want to thank all the comments. It is helping me figure out what to do. It looks like I will just do what everybody else did in my position at different venues in the area is get the hottest fixture in that time period. Creativity is good in lighting but not in electricity. It would be great though if the racks were wired in such a way that would accept 208v modules that etc would make in my alternate reality. Yeah, wouldn't that be great. Is it really that bad of an idea. And would it really be that hard to do? Although led's might make 208v less important in the future.


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## Footer (Jul 11, 2013)

lightguywcl said:


> It would be great though if the racks were wired in such a way that would accept 208v modules that etc would make in my alternate reality. Yeah, wouldn't that be great. Is it really that bad of an idea. And would it really be that hard to do? Although led's might make 208v less important in the future.



Issue there is what do you do on the other end of the rack? If you still have a stagepin plug, you now have a stagepin plug with hot 208 on it instead of 120. You then have to build stagepin Y cables to L6-20 adapters... which are illegal because stagepins are not rated for 208 AND you run the possibility of having a free hot if something gets unplugged.

This really is not that hard of stuff. A 100 amp distro to socapex will run you 1500 bucks or so. Swap a few socapex cables over, label them well, put on new fanouts, and your set to go.


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## JCarroll (Jul 11, 2013)

Maybe I'm missing something but you have a male end of that so apex somewhere. Somewhere they all come out to where you have a sort of patch panel into your dimmer. What is keeping you from buying a 208v soca distro and jumping that into your feeder that goes to your dimmer? Get the proper breakouts and label the soca runs on 208 well and you're good to go.


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## David Ashton (Jul 11, 2013)

I also may be missing something but why not just buy some transformers?


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## lightguywcl (Jul 11, 2013)

> Issue there is what do you do on the other end of the rack? If you still have a stagepin plug, you now have a stagepin plug with hot 208 on it instead of 120. You then have to build stagepin Y cables to L6-20 adapters.


 I would not do it that way. I would build breakouts with 3 L6-20 plugs on them.


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## lightguywcl (Jul 11, 2013)

> Maybe I'm missing something but you have a male end of that so apex somewhere. Somewhere they all come out to where you have a sort of patch panel into your dimmer. What is keeping you from buying a 208v soca distro and jumping that into your feeder that goes to your dimmer.



That is an interesting idea. It is worth some more thought. All my socapex cables are hard wired into the etc sensor rack. I guess it would be possible to make a patch panel between the socapex and the dimmer rack and then have a 208v distro to plug in where I need it.


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## lightguywcl (Jul 11, 2013)

> I also may be missing something but why not just buy some transformers.



I have seen some shows from Europe that will use transformers so they can use their stuff. Would they be point of use transformers? What would I search for if I wanted to look for them online?


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## David Ashton (Jul 11, 2013)

just google transformer 120v 208v at the VA rating you want, there is a huge range here in Perth, so it should be easy in the huge US market


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## DELO72 (Jul 11, 2013)

Agreed. you can't (or good lord, you shouldn't) turn 120v into 208. 120V is all on one phase. 208 is three phase. Get a distro rack and go out of the company switch, which hopefully the building has.
You can buy a fancy one like this below, or make your own (and then hire a certified Electrician to approve/check before using), or hire an electirician to make one for you. 

PowerRACK™ Rolling Distribution Racks: 200 Amp PowerRACK with (24) 208 VAC Circuits and Metering | Lex Products


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## Chris15 (Jul 11, 2013)

So a quick look at the VL3000 spec sheet shows it has a max power consumption in the order of 2400VA.
So that means you'd need a 2.5kVA or more likely 3kVA transformer per fixture.

A quick google says that you're in the ballpark of a grand each for a transformer of that size...

That new distro is looking more attractive by the minute...


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## STEVETERRY (Jul 11, 2013)

DELO72 said:


> Agreed. you can't (or good lord, you shouldn't) turn 120v into 208. 120V is all on one phase. 208 is three phase.



Err....not exactly. The moving light load we are discussing is a 208V _single-phase _load. However, that single-phase power needs to come from two of the three phases, each of which is 120V above ground. That is why a two-pole, _common-trip_ (not "double throw" as mentioned earlier) breaker is required. Nevertheless, this is a 208V _single phase_ circuit.

Reason to use a transformer:
--If there is no 208V (or 240V) power available within a reasonable distance.

Reasons not to use a transformer:
--Cost
--Weight
--Very inefficient

ST


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## JD (Jul 11, 2013)

It's a nice thing that more and more equipment is coming through with auto-ranging power supplies. 208 equipment has one drawback: Short of a transformer, you can't use it in a facility that has single phase (240) power (although, pretty rare in theater.) Likewise, 240 equipment leaves you stuck in a single phase building unless you happen to have Delta. (Also not too common.) 

It is always mind boggling for an old-timer like myself to pick a piece of equipment and see: "Voltage- 90~260" on the plate!


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## FatherMurphy (Jul 11, 2013)

Another good reason to avoid even considering trying to siamese dimmer modules together with a homemade trip lever is the way the racks are laid out for phasing - Strand CD-80 racks are six columns wide, AABBCC, and ETC Sensor racks are laid out with all the A phase in the top 1/3, B in the middle 1/3, and C at the bottom 1/3. You'd have Rube Goldberg linkages running all over....

Getting started the right way will be the cheapest in the long run.


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## lightguywcl (Jul 11, 2013)

> Err....not exactly. The moving light load we are discussing is a 208V single-phase load. However, that single-phase power needs to come from two of the three phases, each of which is 120V above ground. That is why a two-pole, common-trip (not "double throw" as mentioned earlier) breaker is required. Nevertheless, this is a 208V single phase circuit.



I knew I was going to have to meter it to see if it is even possible. I know that I can't get 208v with the same phase hot. I did not know that is was called 208v single-phase load. That phrase is a little misleading to me. Is there a such of a thing as a 208v 3 phase load? I know that there is nothing called a 208v 2 phase load. I am guessing that 2 pole could mean two hots but I would think common-trip and double throw would be saying the same thing. Is there a difference? If I can't get 3 208v circuits off of my socapex drops then this line of discussion is moot. And hearing from some of you there looks like there is little hope in that.


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## Footer (Jul 11, 2013)

lightguywcl said:


> I knew I was going to have to meter it to see if it is even possible. I know that I can't get 208v with the same phase hot. I did not know that is was called 208v single-phase load. That phrase is a little misleading to me. Is there a such of a thing as a 208v 3 phase load? I know that there is nothing called a 208v 2 phase load.



A 3 phase wye disconnect can have 3 208v single phase loads, 3 120v loads, a 208v 3 phase load, or a combination of the above depending on how its wired. The only true 3 phase loads we deal with are motors. 



lightguywcl said:


> I am guessing that 2 pole could mean two hots but I would think common-trip and double throw would be saying the same thing. Is there a difference? If I can't get 3 208v circuits off of my socapex drops then this line of discussion is moot. And hearing from some of you there looks like there is little hope in that.



Not off your current drops if they are hard wired in. Nothing stopping you from connecting a distro with 208v soca outputs to your company switch and running new soca to each pipe. That would give you 6 208 circuits per drop. Get breakouts with L6 20 connectors and your off to the races. 



Sent from my Nexus 7 using Tapatalk HD


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## derekleffew (Jul 11, 2013)

lightguywcl said:


> ... I know that there is nothing called a 208v 2 phase load. I am guessing that 2 pole could mean two hots but I would think common-trip and double throw would be saying the same thing. Is there a difference? ...


Some wiki terms:
split-phase / bi-phase
Circuit breaker, common-trip
throw

.


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## RickR (Jul 11, 2013)

lightguywcl said:


> I knew I was going to have to meter it to see if it is even possible. I know that I can't get 208v with the same phase hot. I did not know that is was called 208v single-phase load. That phrase is a little misleading to me. Is there a such of a thing as a 208v 3 phase load? I know that there is nothing called a 208v 2 phase load. I am guessing that 2 pole could mean two hots but I would think common-trip and double throw would be saying the same thing. Is there a difference? If I can't get 3 208v circuits off of my socapex drops then this line of discussion is moot. And hearing from some of you there looks like there is little hope in that.



208 single phase is a really 120/208 3 phase with no load on one leg or the neutral.

So you are seeing 2 phases, which is why derekeflew linked to all those terms. Common residential 120/240 systems are called single phase because the two are exactly opposite of each other. I believe (but can't find a ref) that early electrical was 2 hots only. If you only have 2 wires you only have one phase. Pick up a ground somewhere and you get a whole other set of voltages.

Clear as mud!


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## STEVETERRY (Jul 12, 2013)

RickR said:


> 208 single phase is a really 120/208 3 phase with no load on one leg or the neutral.
> 
> So you are seeing 2 phases, which is why derekeflew linked to all those terms. Common residential 120/240 systems are called single phase because the two are exactly opposite of each other. I believe (but can't find a ref) that early electrical was 2 hots only. If you only have 2 wires you only have one phase. Pick up a ground somewhere and you get a whole other set of voltages.
> 
> Clear as mud!



Unfortunately, not so clear.

1. Residential 120/240 systems are called single phase because they are just that: the transformer primary is fed only one phase of the distribution system and the 120 volts is derived from a center-tap grounded neutral on the 240V secondary. Because of this center-tap, the two hot legs are 180 degrees out of phase--but they are still single-phase.

2. "Pick up a ground somewhere and you get a whole other set of voltages." Actually--no. A _ground_ means a safety grounding conductor, and is never a current carrying conductor except during a ground fault. A _grounded neutral conductor_ is the center of a wye secondary that gets you 120V from a 120/208V secondary.

ST


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## TimMiller (Jul 12, 2013)

So this brings up another debate. On a mover (208/240 voltage) wired to an L6-30 on the distro side do you wire the grounding lug on the connector to neutral or ground?


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## derekleffew (Jul 13, 2013)

TimMiller said:


> So this brings up another debate. On a mover (208/240 voltage) wired to an L6-30 on the distro side do you wire the grounding lug on the connector to neutral or ground?


Debate? Should be no debate.


There's terminals X, Y, and G. I don't see any marked N.


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## TimMiller (Jul 13, 2013)

I feel the same way but you can find people who will debate anything and here is when the debate comes in. On some old movers I have seen they tie off to ground to get 120v for the power supply to the logic board. Which really should be a neutral rather than a ground but in digital circuits grounding is a must because that's where your 0 reference voltage comes from. Also at the service entrance the ground and neutral should be bonded together which then some people say does it really matter? To me if the connector has a ground marking that connector will be wired to ground end of story (unless the building is old and has no ground but then that requires some different wiring) Next debate I have regarding the same connectors when using 12/3 SO cable does it truly matter if if black and white are wired to either x or y? I have always wired black to X white to Y.


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## SteveB (Jul 13, 2013)

TimMiller said:


> ) Next debate I have regarding the same connectors when using 12/3 SO cable does it truly matter if if black and white are wired to either x or y? I have always wired black to X white to Y.



Yes it matters.

If you use those cables say for a practical and wire up a medium screw base lamp socket and your hot/neutral is reversed, the button contact is now neutral and the screw contact is hot. Potentially a dangerous scenario and not at all an expected wiring configuration. 

We still use old-style twist connectors in one space and have too many of the connectors that used the X/Y coding, rather then brass/copper. We test every cable, adapter, two-fer and unit every year with a standard neon circuit analyzer. We would go crazy with all the Hot/Neutral reversed errors if we did not pay attention to correct wiring habits.


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## Footer (Jul 13, 2013)

SteveB said:


> Yes it matters.
> 
> If you use those cables say for a practical and wire up a medium screw base lamp socket and your hot/neutral is reversed, the button contact is now neutral and the screw contact is hot. Potentially a dangerous scenario and not at all an expected wiring configuration.
> 
> We still use old-style twist connectors in one space and have too many of the connectors that used the X/Y coding, rather then brass/copper. We test every cable, adapter, two-fer and unit every year with a standard neon circuit analyzer. We would go crazy with all the Hot/Neutral reversed errors if we did not pay attention to correct wiring habits.



For whatever reason when our new PA was installed in 2002, they chose to go wtih L6-20 and L6-30 connectors for our isolated "sound" power. We already had L5-20 and L5-30's onstage for lighting power. So, I have a stage full of 120v L6-20 and L6-30 connectors. With that I have heaps of doghouses, cable, and all that stuff that goes along with doing band power. To add insult to injury, whoever wired the L6-20 connectors put the hot on X and whoever did the L6-30 cable put the hot on Y. Geniuses, I know. Luckly I have no L6 208v power in the building unless we have a rented distro for projector power or something like that.


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## Chris15 (Jul 13, 2013)

SteveB said:


> If you use those cables say for a practical and wire up a medium screw base lamp socket and your hot/neutral is reversed, the button contact is now neutral and the screw contact is hot. Potentially a dangerous scenario and not at all an expected wiring configuration.



Now remember I don't play with these plugs in actuality, just in theory.
But this comment perplexes me...
As I understand it, X and Y are 2 actives, so neither of them is at neutral potential and it seems unlikely that anyone would ever be using a 208 / 240 lamp in a practical, everything I've come to understand about your slightly eccentirc electrical system suggests that would be done down at 120...


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## TimMiller (Jul 13, 2013)

L6-30 should only be used for 240/208 volts. L5-30 is designed to be used for 120v circuits.


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## Footer (Jul 14, 2013)

TimMiller said:


> L6-30 should only be used for 240/208 volts. L5-30 is designed to be used for 120v circuits.



Yup! Can't agree more. 

Sent from my Nexus 7 using Tapatalk HD


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## SteveB (Jul 14, 2013)

Chris15 said:


> Now remember I don't play with these plugs in actuality, just in theory.
> But this comment perplexes me...
> As I understand it, X and Y are 2 actives, so neither of them is at neutral potential and it seems unlikely that anyone would ever be using a 208 / 240 lamp in a practical, everything I've come to understand about your slightly eccentirc electrical system suggests that would be done down at 120...



The older style twist lock connectors (known as tit out) used for 120v distribution, I think they are L7-20's (can't remember) was once a Brass (Hot), Copper (Neutral) plus ground configuration. The male was not a "dead front" connector, instead had a fibre plate covering the screw terminals and neither the male nor the female had any X,Y,Z indications. Then the connector got changed to a 2 hot with ground configuration, became the modern dead front design and got indicators for X and Y, but stayed "tit-out". This is still the only twist locking style connector that interfaces with the the original design (in old spaces) and is what's used. 

For assorted reasons, our space using twist, which was supposed to convert to 2P&G 2 years ago, has not, thus we continue to use twist. Hate them.


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## derekleffew (Jul 14, 2013)

SteveB, Chris15, (et al), see the wiki entry TLGO (and TLGI) (and the thread http://www.controlbooth.com/forums/...38-old-non-nema-pin-out-style-twistlocks.html ). When wiring this connector for 250V (H,H,G) it doesn't matter which hot XY goes to brass or copper colored terminals. When wiring for 120V (H,N,G) black H _should_ go to brass, and white N _should_ go to copper (_I think_, see below), but it's understandable how this could get confused. 

At least it's not the connector discussed here, which is neither ground-out nor ground-in:

derekleffew said:


> PeteEngel said:
> 
> 
> > ... as for wiring, yes, the biggest blade is ground, and the blade at the 4 to 5 o'clock position "should" be the Neutral, but that should be indicated inside the connector. ...
> ...



The above makes me grateful for how far we've come thanks to NEC, UL, NEMA. It's nice being reasonably certain of voltage and polarity when encountering any connector. Sadly, we can never be 100% without testing due to scofflaws and ignoramuses.
.


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## STEVETERRY (Jul 14, 2013)

SteveB said:


> The older style twist lock connectors (known as tit out) used for 120v distribution, I think they are L7-20's (can't remember) was once a Brass (Hot), Copper (Neutral) plus ground configuration. The male was not a "dead front" connector, instead had a fibre plate covering the screw terminals and neither the male nor the female had any X,Y,Z indications. Then the connector got changed to a 2 hot with ground configuration, became the modern dead front design and got indicators for X and Y, but stayed "tit-out". This is still the only twist locking style connector that interfaces with the the original design (in old spaces) and is what's used.
> 
> For assorted reasons, our space using twist, which was supposed to convert to 2P&G 2 years ago, has not, thus we continue to use twist. Hate them.



Tit-out twist-loks are non NEMA rated. They have a dual 125/250V rating--which is precisely why they are non-NEMA. Unlike the 2P&G pin plug dual voltage rating, which requires one conductor to be a grounded neutral--the tit-out rating is hot-neutral at 125V and hot-hot at 250V. That's why they disappeared over the last 20 years.

ST


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## lightguywcl (Jul 16, 2013)

I appreciate all the comments I have got so far and I have tried to come up with a plan that most people would agree with. I went into work today and tested my socoapex breakouts. Circuit 1-x, 2-y, 3-y, 4-z, 5-z, 6-x. So I do get 2 of each leg in all of my breakouts. So my plan is to get 24 cc modules and build two circuit breaker boxes with two male socoapex connectors going in and one female going out. With 6 15 amp double pole breakers in the middle. I plan on hanging it right on the pipe that the movers are on. This is the cheapest and code friendly idea I have come up with so far to get 208v. I am interested in what everybody thinks. Thank you.


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## Footer (Jul 16, 2013)

lightguywcl said:


> I appreciate all the comments I have got so far and I have tried to come up with a plan that most people would agree with. I went into work today and tested my socoapex breakouts. Circuit 1-x, 2-y, 3-y, 4-z, 5-z, 6-x. So I do get 2 of each leg in all of my breakouts. So my plan is to get 24 cc modules and build two circuit breaker boxes with two male socoapex connectors going in and one female going out. With 6 15 amp double pole breakers in the middle. I plan on hanging it right on the pipe that the movers are on. This is the cheapest and code friendly idea I have come up with so far to get 208v. I am interested in what everybody thinks. Thank you.



There is no way that every single breakout has that exact configuration in how the phases line up. Though I can not site the exact code, I can't imagine a situation where a common throw breaker is allowed downstream of two non common throw breakers is allowed. If you have an issue on the line, you run the risk of the breaker on the dimmer rack blowing instead of the breaker on the load side, especially when both breakers are rated the same. It is pretty much a crap shoot as to which one will blow first. 

I don't think we can say this enough here... there is *NO LEGAL OR SAFE WAY* in which you will be able to get 208v service out of your currently installed sensor rack and distribution. If you can't afford to do it right, you should not be doing it. If your looking at buying a 100k in fixtures, I have no clue what your problem is with purchasing a proper distro. Why would you jump through all of these hoops to save a few grand? 

Here is one for 2k:LEX 200 Amp 3 Phase Moving Light Box | Power Distribution Boxes for Stage, Theatre and Live Performance | PNTA
Two 100' socapex cables for a grand: https://www.gearsource.com/catalog/listing/40175
Two nice L6-20 Breakouts for 300 bucks: https://www.gearsource.com/catalog/listing/49971
and some oversized feeder for a grand: 50' Feeder Cable

So, $4,500 and you have 12-20amp circuits of 208v power that is safe. So, what is the deal? Why are you jumping through these hoops? 5k is nothing crap compared to what 10 top level movers cost. You will spend 5k a year alone in lamps and maintenance on 10 units.


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## techieman33 (Jul 16, 2013)

lightguywcl said:


> I appreciate all the comments I have got so far and I have tried to come up with a plan that most people would agree with. I went into work today and tested my socoapex breakouts. Circuit 1-x, 2-y, 3-y, 4-z, 5-z, 6-x. So I do get 2 of each leg in all of my breakouts. So my plan is to get 24 cc modules and build two circuit breaker boxes with two male socoapex connectors going in and one female going out. With 6 15 amp double pole breakers in the middle. I plan on hanging it right on the pipe that the movers are on. This is the cheapest and code friendly idea I have come up with so far to get 208v. I am interested in what everybody thinks. Thank you.




Footer said:


> There is no way that every single breakout has that exact configuration in how the phases line up. Though I can not site the exact code, I can't imagine a situation where a common throw breaker is allowed downstream of two non common throw breakers is allowed. If you have an issue on the line, you run the risk of the breaker on the dimmer rack blowing instead of the breaker on the load side, especially when both breakers are rated the same. It is pretty much a crap shoot as to which one will blow first.
> 
> I don't think we can say this enough here... there is *NO LEGAL OR SAFE WAY* in which you will be able to get 208v service out of your currently installed sensor rack and distribution. If you can't afford to do it right, you should not be doing it. If your looking at buying a 100k in fixtures, I have no clue what your problem is with purchasing a proper distro. Why would you jump through all of these hoops to save a few grand?
> 
> ...



Based on footers links your not saving any money at all by doing it the wrong way. I still don't understand why your so driven to use the dimmer rack for power after we've all told you it can't work. 

24 cc modules will run you about $3230 plus shipping at production advantage, so yeah maybe you could find them a little bit cheaper.
$500 for breakers boxes and breakers (ballpark guess)
$500 in Soca connectors for the breakers boxes
$300 L6-20 breakouts
$600 stage pin break in's

That's already got the total up to $5130, not including all of the labor to build those illegal breaker boxes which won't be cheap. And you've also lost 24 channels of dimming that may need to be replaced $$$. 

And then there are the really big costs to think about. The first one is your show getting shutdown by the fire marshal or another inspector, when they see breaker boxes in the air you won't have time to think up a reason before they shut you down. What happens when something fails does serious damage to your dimmer rack? And then there is the big fat lawsuits that will come raining down on you and the venue when someone gets hurt from this. 

Please do us all a big favor and save a few dollars by doing it the right way. 


$


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## derekleffew (Jul 17, 2013)

lightguywcl said:


> ... I went into work today and tested my socoapex breakouts. Circuit 1-x, 2-y, 3-y, 4-z, 5-z, 6-x. So I do get 2 of each leg in all of my breakouts. ...




Footer said:


> There is no way that every single breakout has that exact configuration in how the phases line up. ...


One would hope all the breakouts are wired according to industry standard: http://www.tmb.com/images/stories/6-circuitpinout-ltr.pdf . 
Now IF (big if) the female socapex outlets (dimmer outputs) are wired starting as mult circuit#1 is dimmer#2 [or 8, or 14, or 2+(x*6)], then phasing would indeed be "1-x, 2-y, 3-y, 4-z, 5-z, 6-x." 
But it's more likely each soca outlet begins with: 1, 7, 13, 19 ... 1+(x*6), in which case the phasing would be 123456=XXYYZZ.

Which brings up a, very real, potential issue with the proposed scheme: if the outlets are not all wired the same, or start with the same phase dimmers, or a multi-cable has crossed wires, or a break-out has a hot-neutral reverse; any of seemingly minor errors will cause the system to be: inoperable at best, unsafe at worst.


lightguywcl said:


> ... and build two circuit breaker boxes with two male socoapex connectors going in and one female going out. With 6 15 amp double pole breakers in the middle. I plan on hanging it right on the pipe that the movers are on. This is the cheapest and code friendly idea I have come up with so far to get 208v.


Will this "box" be designed, assembled, and tested by a UL Listed 1640 assembler? How does the theatre's insurance carrier feel about the use of a "homemade" piece of electrical distribution equipment?


lightguywcl said:


> ... This is the cheapest and code friendly idea I have come up with so far to get 208v. I am interested in what everybody thinks. Thank you.


Cheapest = no.
Code friendly = no.

If you insist in not using a dedicated ML PD (the consensus here), consider this listed, by NRTL device: Quick 220 Systems: Model A220-20L <br />20 Amp Power Supply <br />Twist Locking Outlet as discussed in here: http://www.controlbooth.com/forums/lighting-electrics/19720-115-volt-ac-220-volt-ac.html#post179043 . The specs don't mention it working with 120/208V bi-phase, so I would inquire before purchase. I don't see why it wouldn't. I also don't see why anyone would want to introduce such a point of potential failure into his system, but there you go.
EDIT: Response from the manufacturer:

> Thank you for asking about Quick 220 systems. In answer to your question, the Quick 220 can be used on the two 120V circuits of a 3 phase Wye system. As you indicated, the output voltage is then 208 volts, nominal. Although we don't emphasize 3 phase power as a source, it is covered on the specification section of the product page: http://www.quick220.com/-A220-20L.html . Although the output with 3 phase is 208 volts, nominal, we give the range of "187 to 216 Volts AC (1.732 times input voltage)” which reflects the output if the input varies from 120 volts.


-----

Footer said:


> ... and some oversized feeder for a grand: 50' Feeder Cable


From the listing:

> 50' Feeder Cable with Cam-Locks. Red Blue & Black are 4/0 cable. White and Green are 2/0 cable.


1. Don't buy from a vendor who can't spell cam-lok.
2. We've discussed previously code compliability of using a smaller ground, but I don't think we've ever discussed an under-sized neutral.
3. For this particular application (feeding a 200A distro), a 2/0 neutral is acceptable. Even more so when one considers that the neutral isn't even connected to the outputs (except for the "(1) NEMA 5-20, 20 Amp, 2 Pole, 3 Wire, 120 VAC, duplex receptacle" convenience outlet on the LEX pagoda box). But this assembly wouldn't be permitted to supply a dimmer rack.
4. We've also discussed previously the derating required when 4/0 feeder is bundled.

.


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## Footer (Jul 17, 2013)

derekleffew said:


> O
> 1. Don't buy from a vendor who can't spell cam-lok.
> 2. We've discussed previously code compliability of using a smaller ground, but I don't think we've ever discussed an under-sized neutral.
> 3. For this particular application (feeding a 200A distro), a 2/0 neutral is acceptable. Even more so when one considers that the neutral isn't even connected to the outputs (except for the "(1) NEMA 5-20, 20 Amp, 2 Pole, 3 Wire, 120 VAC, duplex receptacle" convenience outlet on the LEX pagoda box). But this assembly wouldn't be permitted to supply a dimmer rack.
> ...



One would also hope that you would not buy an entire rig off of gearsource... there are much better prices out there if you just pick up the phone!

The point of the post was not to spec gear for his exact rig but instead to show that you can buy what you need for pennies compared to the cost of the fixtures themselves. Personally though if I had a 400 amp company switch I would probably buy 4/0 feeder anyway. It is not that much more after you figure in the connectors and shipping. Down the line your not purchasing new cable if you want use the full capacity of the switch. Now, if I had to move it every day I would be singing a different tune... and rather loudly.


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## lightguywcl (Jul 17, 2013)

The original point of this post was to find out if my idea was legal and cost effective. My TD will not allow me to do it if it isn't. I have been a Head Electrician for 20 years and I will not build something if I feel that it is in anyway unsafe. 

My thought was to first figure out if it was safe. If it was not then I did not need to find out if it was cost effective. 


> There is no way that every single breakout has that exact configuration in how the phases line up




> Which brings up a, very real, potential issue with the proposed scheme: if the outlets are not all wired the same, or start with the same phase dimmers, or a multi-cable has crossed wires, or a break-out has a hot-neutral reverse; any of seemingly minor errors will cause the system to be: inoperable at best, unsafe at worst.



It is true I have not tested every breakout but I have tested every breakout I plan on using and they are the same. I have been using the term breakout but that is for testing purposes only. I am using one breakout and moving it to the places I want to test. So there is no problem with a hot-neutral reverse. I can only say that it has been the same so far and I will test more of them if I plan on going ahead with this. 


> If you have an issue on the line, you run the risk of the breaker on the dimmer rack blowing instead of the breaker on the load side, especially when both breakers are rated the same. It is pretty much a crap shoot as to which one will blow first


. 

This is where I would like to get some more input on. This seems to be the biggest problem. I had stated that I would use 15 amp double pole breakers and there would be 20 amp single pole breakers up stream of that. So there would be no crap shoot problem. As long as the breakers are lower than the breakers upstream. How is that wrong? 


> Will this "box" be designed, assembled, and tested by a UL Listed 1640 assembler? How does the theatre's insurance carrier feel about the use of a "homemade" piece of electrical distribution equipment?



I am not sure how to answer that. Other than it will not be. My TD has requested plans on anything I am proposing to build. It will probably be looked at by the people that will be upgrading the etc sensor rack system. The building is owned by the city so it is self insured. Maybe a city electrician will look at it as well. Believe me this will not be done in secret. This will be checked by several people. 


> Based on footers links your not saving any money at all by doing it the wrong way. I still don't understand why your so driven to use the dimmer rack for power after we've all told you it can't work.



I will take no for an answer if it is explained to me the reasons why. The reason why I am so driven is curiosity and education. If it is not safe I did not see the logic in checking the cost. Yes several people have told me that it won't work. I have changed my idea a little to see if it could work. I can only address the concerns everybody has and answer them. If I can't then I will feel comfortable in going in a more conventional direction. 

In conclusion I had an idea that I thought would work. I am trying not to appear than I'm obstinate and I try to answer each question in a logical manner. I did not want to propose this plan to my TD unless I thought it was safe and cost effective. That is why I had brought this up in this forum to get some ideas and information. I am happy with all the responses I have gotten so far. The only thing that is left to ask is that if my current idea is safe and not to crazy of an idea. I hope I have answered some of the questions that were proposed earlier in this tread. And I hope I can get feedback on why it is unsafe. Thank you.


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## sk8rsdad (Jul 17, 2013)

The fundamental problem with the approach of extracting 208V power from a Sensor rack is the circuit cannot be de-energized by a common breaker. End of story. No amount of wishful thinking or clever crafting can resolve that problem.

There are 2 locations in the rack where it might be possible to install a module with a common breaker that would span 2 phases. However, ETC does not manufacture such a contraption. Bodging something yourself invalidates any existing approvals. Consequently there is no UL or NEC approved way of getting a 208V circuit out of the rack.


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## DuckJordan (Jul 17, 2013)

Not to mention its not cost effective, nor should any tour ever want to use that system. I don't mean to sound rude but experience is useless if its been lessons learned wrong. I know of a head electrician of 25 years who doesn't know squat outside of flipping a breaker or changing a lamp.


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## STEVETERRY (Jul 17, 2013)

lightguywcl said:


> And I hope I can get feedback on why it is unsafe. Thank you.



Here is that feedback:

1. The ETC Sensor dimmer rack is UL listed to feed only 120V grounded-neutral loads, not 208V loads. Connecting a 208V load to the rack violates the UL listing and the conditions of use for the product.

2. If you were foolish enough to add a downstream two-pole circuit breaker, common-trip  to a pair of dimmer outputs on different phases, there is no guarantee of the coordination of the module breaker and the outboard breaker, especially since the outboard breaker is likely to be a thermal breaker and the module breaker is a fully magnetic breaker. You cannot guarantee that the outboard breaker will open first in the event of a fault. If a module breaker were to trip first, you have an unsafe condition at the load since one ungrounded conductor would remain energized.

3. The liability of constructing “home-made”, unlisted power distribution units is considerable. I suggest it is very unwise to head in this direction, since if there is a problem, the solution you are attempting to propose will not stand up to scrutiny by an AHJ.

There are many purchase or rental sources of listed portable power distributions that are designed to solve the problem you have described. I suggest you avail yourself of one of those sources.

Steve Terry
--VP R&D, Electronic Theatre Controls
--Member NEC Code Panel 15—USITT Alternate Representative
--Member, PLASA Electrical Power Working Group
--Member, PLASA Technical Standards Council
--Member, UL Standards Technical Panels 498, 924, 1008, 1340, 1691
--ETCP Certified Electrician
--ETCP Recognized Trainer


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## lightguywcl (Jul 17, 2013)

> The fundamental problem with the approach of extracting 208V power from a Sensor rack is the circuit cannot be de-energized by a common breaker. End of story. No amount of wishful thinking or clever crafting can resolve that problem.



I agree that is the biggest problem. The head of maintenance at my theater worked at UL for a period of time and he has some interesting stories. If it is in fact illegal to have 2 single pole breakers feed a double pole breaker even though it is less amperage. Then I will no longer argue this point. So if it is illegal then it probably has been tested. I am curious on what fails. The Sensor rack is the circuit cannot be de-energized by a common breaker. I am trying not to be dumb but why is that a problem?


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## SteveB (Jul 17, 2013)

lightguywcl said:


> I agree that is the biggest problem. The head of maintenance at my theater worked at UL for a period of time and he has some interesting stories. If it is in fact illegal to have 2 single pole breakers feed a double pole breaker even though it is less amperage. Then I will no longer argue this point. So if it is illegal then it probably has been tested. I am curious on what fails. The Sensor rack is the circuit cannot be de-energized by a common breaker. I am trying not to be dumb but why is that a problem?



Because somebody with a bit less knowledge attempting to trouble shoot the system, might not know that the single Sensor breaker feeding 1/2 of the load is the only breaker, thus won't de-energize the other half. The common trip breaker is idiot proof.


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## lightguywcl (Jul 17, 2013)

> The ETC Sensor dimmer rack is UL listed to feed only 120V grounded-neutral loads, not 208V loads. Connecting a 208V load to the rack violates the UL listing and the conditions of use for the product


. 

This maybe a part of electricity I don't understand. For example if I make 208v out of circuit 318 and 319 it will create a load of lets say 10 amps on each leg back to the 2 circuits to the dimmer rack. Now if I use them normally and plug 2 lights into them how is it different? I have not changed anything on the dimmer rack side. 


> 2. If you were foolish enough to add a downstream two-pole common-trip breaker to a pair of dimmer outputs on different phases, there is no guarantee of the coordination of the module breaker and the outboard breaker, especially since the outboard breaker is likely to be a thermal breaker and the module breaker is a fully magnetic breaker. You cannot guarantee that the outboard breaker will open first in the event of a fault. If a module breaker were to trip first, you have an unsafe condition at the load since one ungrounded conductor would remain energized.



I did not know that a magnetic breaker and a thermal breaker would react differently. I would be buying parts for this box and I could make sure that they are also fully magnetic. 


> 3. The liability of constructing “home-made”, unlisted power distribution units is considerable. I suggest it is very unwise to head in this direction, since if there is a problem, the solution you are attempting to propose will not stand up to scrutiny by an AHJ.



I thought I had addressed this. So what you said that must mean that even if it is checked by a city electrician that it does not absolve me from liability because I built it. Of course if what everybody said was true than a city electrician would never approve it. So it would not get built so no liability. 


> If a module breaker were to trip first, you have an unsafe condition at the load since one ungrounded conductor would remain energized.



I know that is a problem. Though I still don't know why. As you know that is what I am trying to address. Hence the full magnetic 15 amp 2 pole breaker. Also why is it an ungrounded conductor? I just want to say that I have learned so much more that when I started this post. I am still glad that I presented this idea so I can learn more about my craft.


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## lightguywcl (Jul 17, 2013)

> Because somebody with a bit less knowledge attempting to trouble shoot the system, might not know that the single Sensor breaker feeding 1/2 of the load is the only breaker, thus won't de-energize the other half. The common trip breaker is idiot proof.



As I was thinking about this problem that is the only thing I could think of on why it would be wrong. The system would not fail and cause a electrical fire. I can't think of on how it could. If that is the case then everything can just be unplugged to be serviced you would not have to turn off the breakers. I don't know why it would have to be more idiot proof than that. If everything was hardwired in I could see it become an issue.


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## Wood4321 (Jul 17, 2013)

I am getting very frustrated reading this, I guess I just don't understand your aversion to doing this the "legal" and "Correct" way?
You are correct, it is very unlikely that the AHJ will allow you to use the home make box, but even if it were allowed, it shouldn't be.
(People, including electrical inspectors make mistakes)

There is literally no way to build this box to do what you want it to do legally, and without voiding the UL listing on the dimmer rack at the same time.

There is no way to ensure which breaker blows first, even if one is lower amperage, and the same type.

I also would suggest you show your TD this thread, so that He or She understands what is going on, and the downside of what you proposing.

In any case Please listen to Steve Terry, and many other who have posted in this thread.
Buy a 208v power distro. It is the only way to go in this circumstance.


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## PeteEngel (Jul 17, 2013)

I agree. I had a long reply to the OP disappear on me and before I could get back a number of people have posted. 

As a purely mental exercise it is interesting to consider. As practical exercise it is a HUGE waste of time. 

Please, call ETC and ask if they consider their Sensor Rack as a power source for a makeshift 208v distro. Any number of projects have had people try and push the limits of whatever gear they have. Don't be a tragic statistic. My guess is that the UL rating of the Sensor rack will be void in this circumstance and any issues that arise will then be directly laid upon the facility and YOU (the OP). 

The OP has already spent WAY TOO MUCH TIME on this dead end. But I do have an idea that would help. How about finding some Moving Lights that can operate on 110v power? If you have $100k to spend I'm sure they are out there. 

Just Sayin'...

Jeez.


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## lightguywcl (Jul 17, 2013)

I want to be perfectly clear so my TD understands this. I will not make a box that is "illegal" and "incorrect". He knows what my idea is and he knows I am in a discussion here to see if it is viable. When I came up with this idea I wanted to find out if it could work. So I thought this would be a good forum to ask this question. Where is the harm in doing this? I have not done anything other than explore the idea. With my knowledge I thought it could work so I asked this forum to people that have more knowledge than I. So as a result I have more knowledge than I did before. Even if it is a failed idea I still have learned something. I am sorry if I am frustrating some people I am just trying to understand better.


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## lightguywcl (Jul 17, 2013)

> The OP has already spent WAY TOO MUCH TIME on this dead end. But I do have an idea that would help. How about finding some Moving Lights that can operate on 110v power? If you have $100k to spend I'm sure they are out there.



I have already talked to my TD today and told him that it is better to go with 8 martin vipers and 8 auras along with a grand ma 2 lite. We will see how close we are to get to that $150,000.00 and then see what else we can add to it. I would like to thank everybody's comments it has helped me to decide what to do. So yes it is purely a mental exercise at this point but I would still like to know more about why it won't work for my own information. Again thank you.


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## RonHebbard (Jul 17, 2013)

lightguywcl said:


> I agree that is the biggest problem. The head of maintenance at my theater worked at UL for a period of time and he has some interesting stories. If it is in fact illegal to have 2 single pole breakers feed a double pole breaker even though it is less amperage. Then I will no longer argue this point. So if it is illegal then it probably has been tested. I am curious on what fails. The Sensor rack is the circuit cannot be de-energized by a common breaker. I am trying not to be dumb but why is that a problem?



Hello!

I'm flogging the horse here but please permit me to elaborate on a couple of things Steve Terry told you.
ETC uses magnetic trip breakers, as they should / must.
A 20 amp magnetic trip breaker could easily trip before a thermal trip 15 amp breaker.
No one would be surprised and no laws of physics would be broken.

If you use a pair of single pole breakers to feed your downstream common trip pair of breakers, when one of the source breakers trips, power from the second source breaker will pass through one pole of your common trip breaker, continue through your load, return, backwards as it were, through your other common trip breaker and end up on the load terminal of the source breaker that tripped. This can really catch folks off guard when they meter before and after a tripped breaker and find voltage on both sides. They can also be easily caught off guard, and/or killed, when a load device ceases to function yet is still sitting there with 120 volts just waiting for an unsuspecting grounded human being to innocently dig into it.

I'm sorry if we're not getting through to you and I don't want you to feel that a bunch of jerks on the internet are ganging up on you for fun and amusement. I just wish I could find the words to convince you that you've received a lot of great advice from a lot of very experienced people who're giving of their time for free all in an effort to help and educate you.

EDIT: I too began writing this post a while ago and note several posts have added to this thread whilst I was typing away.

I'll quit flogging and go away now.

Steve? We met for two days in a boardroom in your then new New Jersey shop back in 1995 when about a dozen of us were gathered to plan taking 'Tommy' to Frankfurt dancing to the rules of TUV. I ended up spending six weeks in a really nice Frankfurt hotel and returned home to Canada with too, too many really silly stories, mostly involving German rental shops and too long to get into here. 
Are you still in touch with Dave Grill?
Ask Dave about him and the VL programmer, drunk as skunks, standing amidst the pitchers on a large circular table belting out 'God Bless America' in a room of 1,000 elegantly dressed German folks singing their national anthem at the Tommy opening night party while Gene O'D and Linda Batwin were trying to slide out of sight under the table in embarrasment.

Dealing with TUV actually worked out well in the end, smuggling six bottles of A1 steak sauce into Germany had a lot to do with it.

Toodleoo!
Ron Hebbard


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## lightguywcl (Jul 17, 2013)

> If you use a pair of single pole breakers to feed your downstream common trip pair of breakers, when one of the source breakers trips, power from the second source breaker will pass through one pole of your common trip breaker, continue through your load, return, backwards as it were, through your other common trip breaker and end up on the load terminal of the source breaker that tripped. This can really catch folks off guard when they meter before and after a tripped breaker and find voltage on both sides. They can also be easily caught off guard, and/or killed, when a load device ceases to function yet is still sitting there with 120 volts just waiting for an unsuspecting grounded human being to innocently dig into it.



Wow I had no idea that that would happen. So what that would mean then if I understand what you are saying that if one leg trips then the tripped side becomes the neutral of the other hot leg? Is that correct? When I talked to the tech at vari-lite he said that if you lost one leg it would still work on 120v just not as bright. In this instance it would be really difficult to meter both sides of the tripped breaker since it would be a etc dimmer module. I can't think of how I could meter it even if I wanted to since it is hard wired back to the dimmer rack. I maybe able to open a junction box but why would I want to. The most likely cause of the tripped breaker is the vl3000 which would have to cause such an action that would not blow the internal fuses and get past the double pole breaker and finally trip the 20 amp single pole breaker. I don't even know if that is possible at the most it is unlikely. The only other way it could trip would be a short circuit in the wiring which would also be unlikely but possible. 


> I'm sorry if we're not getting through to you and I don't want you to feel that a bunch of jerks on the internet are ganging up on you for fun and amusement. I just wish I could find the words to convince you that you've received a lot of great advice from a lot of very experienced people who're giving of their time for free all in an effort to help and educate you.



I have been in other forums and there have been times where people posting threads are not sure how they are coming across. I have said this before and I will say it again I really do appreciate the information I am getting from everybody. I have not felt for a moment that you are a bunch of jerks.


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## sk8rsdad (Jul 17, 2013)

lightguywcl said:


> the tripped side becomes the neutral of the other hot leg? Is that correct?.



Sorry if this seems a bit like Electricity 101, especially to somebody with 20 years experience but...

An electrical circuit needs a closed path from source to load and back again. We use the terms _hot_ and _return_ to describe the two connections between source and load.

Don't confuse the term _return_ with the term _neutral_. In a single-phase circuit, both the hot and neutral are power carrying conductors and the only distinction is that the _neutral_ is bonded to ground at some point. The electrons that change direction 60 times a second in North America don't care which connection is which. They are happily flowing around a closed circuit.

In a 208V circuit provided by a 3-phase Wye (Y) system, there is no neutral. The return is another hot leg, phase-shifted by 120 degrees. If the voltage on either leg is measured relative to ground, both will read 120V. Neither leg is bonded to ground.

Since neither leg in a 208V circuit is bonded to ground, a common double-pole circuit breaker is required to de-energize both legs simultaneously. Failing to de-energize both legs at the source means there is 120V difference between one of the wires in the load and ground. Touching that live wire is hazardous to your health.


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## RonHebbard (Jul 17, 2013)

sk8rsdad said:


> In a 208V circuit provided by a 3-phase Wye (Y) system, there is no neutral. The return is another hot leg, phase-shifted by 120 degrees. If the voltage on either leg is measured relative to ground, both will read 120V. Neither leg is bonded to ground.
> 
> Since neither leg in a 208V circuit is bonded to ground, a common double-pole circuit breaker is required to de-energize both legs simultaneously. Failing to de-energize both legs at the source means there is 120V difference between one of the wires in the load and ground. Touching that live wire is hazardous to your health.



Hello "dad"!
(I far prefer forums where folks use their real names like Steve Terry.)

First of all, thank you for picking up the torch, the OP means well, and I appreciate his desire for education but as with a few other posters he's wearing me down.
I believe I've caught you in a minor typo that ought to be made crystal clear to the OP.
"In a 208V circuit provided by a 3-phase Wye (Y) system, there is no neutral."
A delta sourced system would have no neutral.
A Wye sourced system has a neutral, and by most codes it would be bonded to ground at source, but you may choose not to use the neutral or bring it out from the transformer.

Another possible misunderstanding for the OP.
"Since neither leg in a 208V circuit is bonded to ground, a common double-pole circuit breaker"
I suspect you meant to type 'a double-pole common trip circuit breaker', the trip being common rather than the breaker.

Somewhere far back in this thread, I recall someone alluding to the VL's possibly developing 120 VAC internally by taking a reference from ground as they're not bringing a neutral into the unit. If this is true, I suppose I can understand some of what the OP is attributing to his VL tech.

Thanks again "dad" for continuing the good fight against well intentioned assumptions and dangerous electrical practices.

Oh! In my part of Canada, the electrons change direction 120 times per second completing each full cycle 60 times per second at a good time on a good day when the load's not too heavy and the water's running over the falls real good!

Toodleoo!
Ron Hebbard


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## lightguywcl (Jul 17, 2013)

So my error was saying that it becomes a neutral. I should have said acts like a neutral or used the term return that would describe that the tripped leg would have voltage on it. Now that I think about it "saying acts like a neutral may not be much better" Now that I read it again it does seem silly that I used the term "becomes" like it happened magically. Sorry, poor choice of words. I don't know if there would be voltage on the tripped side. I would think it would depend on what made the breaker trip in the first place. I did know the difference but thanks for the refresher course. I do not think of electricity that much anymore so it is good to remember it again. Everybody keeps on talking about that hot wire. All I can say is it would be really difficult to touch. You would have to get into the back of the rack or take the connector off. Now who would really take a connector off without shutting all of the breakers off anyway.


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## JD (Jul 17, 2013)

The "tripped leg" would still have full line voltage on it. The "load" simply allows the voltage on the opposing hot to flow through it. Since the circuit is now open, no work is being done, but it you were to meter the open leg (assuming 208/120), you would find it 120 volts above ground, but with 0 volts across the load. Because of this, the conductor that is thought to be dead presents a shock hazard. The only exception to this case would be if the tripped line was shorted to ground. At that point, the load would have 120 volts across it instead of 208. More important, when the source of the short was found and corrected, the conductor would jump up to 120 volts and again become a shock hazard. This is why the "break" must be made by a double pole breaker, so that no voltage and shock hazard are present in the shut-down circuit (past the breaker itself.)


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## lightguywcl (Jul 17, 2013)

> The "tripped leg" would still have full line voltage on it. The "load" simply allows the voltage on the opposing hot to flow through it. Since the circuit is now open, no work is being done, but it you were to meter the open leg (assuming 208/120), you would find it 120 volts above ground, but with 0 volts across the load. Because of this, the conductor that is thought to be dead presents a shock hazard. The only exception to this case would be if the tripped line was shorted to ground. At that point, the load would have 120 volts across it instead of 208. More important, when the source of the short was found and corrected, the conductor would jump up to 120 volts and again become a shock hazard. This is why the "break" must be made by a double pole breaker, so that no voltage and shock hazard are present in the shut-down circuit (past the breaker itself.)



I don't think it can be explained better than that. I would again like to thank everybody's time and input. I am now going to enjoy finding gear to spend with my $150,000.00 lighting budget. I would welcome any input anybody has on that subject although I may have to start a new thread. Again thanks.


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## RonHebbard (Jul 17, 2013)

Hello again and again "lightguy..."

Two quick points and I'll go away again.

Back to the scenario where one of your two source breakers trips.
Unless the related load wiring has gone solidly to ground or burned its self open somewhere along the way, all of the load wiring will still have 120 VAC on it with respect to ground, all of it!
You wouldn't need to get into your dimmer rack to get a shock.
If one of your two source breakers tripped, and if your load wiring has not gone solidly to ground or burned its self clear, there would be volage present on the load side of your tripped breaker, no buts or maybes about it.

I guess one of the several dangers here is many of us think we've already explained things but, unless you write back, we've no real way of knowing what you understood from our efforts.
I keep feeling we're not getting through to you and I apologize for my inability to adequately express myself with greater clarity.
Keep coming back and I'll try not to give up on you.

Toodleoo!
Ron Hebbard


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## lightguywcl (Jul 17, 2013)

> If one of your two source breakers tripped, and if your load wiring has not gone solidly to ground or burned its self clear, there would be volage present on the load side of your tripped breaker, no buts or maybes about it.



I appreciate you hanging in there with me so I will stay in it until I completely understand. I know that the power from the untripped leg is being powered by the tripped leg. Since this is an unconventional set up a person not knowing that could shock himself. The connection would be inside the vl 3000 somewhere. I would think then if anybody unplugged any of the possible connections along the way or shut off the double breaker there would be no voltage on the tripped leg. Is that correct? I think everybody knows the setup by now. I know why the electricity is running the way it is. I still don't see how anybody can get shocked even if they don't know the tripped leg is not safe. I honestly can't come up with a scenario. So you offered to help me Ron. Assuming everything else I said was correct it would be a big help if you can come up with a scenario were I can't.


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## len (Jul 17, 2013)

Other options:

Buy a combo distro and dimmer rack (Applied makes them to order, among others) and sell a dimmer rack or two.

Rent a distro as needed


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## lightguywcl (Jul 17, 2013)

> Other options:
> 
> Buy a combo distro and dimmer rack (Applied makes them to order, among others) and sell a dimmer rack or two.
> 
> Rent a distro as needed



Interesting idea I will talk to the people that will be upgrading the dimmer racks to see how much it would be. Now that I will be going the 110v option I will be buying R20 etc modules. I was surprised that they were $450.00 a piece and since they are doubles circuiting them will be problematic. I wish they made just one side a relay. I made several relay dimmers for a nearby theater in a cd80 rack. Those are easy to work on. In this age of moving lights. The future theater may have more straight AC power.


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## RonHebbard (Jul 17, 2013)

lightguywcl said:


> I appreciate you hanging in there with me so I will stay in it until I completely understand. I know that the power from the untripped leg is being powered by the tripped leg. Since this is an unconventional set up a person not knowing that could shock himself. The connection would be inside the vl 3000 somewhere. I would think then if anybody unplugged any of the possible connections along the way or shut off the double breaker there would be no voltage on the tripped leg. Is that correct? I think everybody knows the setup by now. I know why the electricity is running the way it is. I still don't see how anybody can get shocked even if they don't know the tripped leg is not safe. I honestly can't come up with a scenario. So you offered to help me Ron. Assuming everything else I said was correct it would be a big help if you can come up with a scenario were I can't.



Hello!

If you trip, or turn off, your common trip breaker, or unplug any extension cable connectors downstream of it, then everything downstream of wherever you broke all of your conductors will be de-energized / safe.
An example of a hazardous scenario would be one of your two source breakers tripping, or being inadvertantly switched off, the VL appearing to be without power and someone innocently opting to service the VL not realizing it was still partially powered.

All the best.

Toodleoo!
Ron Hebbard


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## derekleffew (Jul 17, 2013)

lightguywcl said:


> ... and since they are doubles circuiting them will be problematic. ...


Under your previous scheme, you were willing to sacrifice 24 channels of dimming to gain 12x L6-20 outlets. Now you're concerned about having to swap modules in multiples of two?


lightguywcl said:


> ... Now that I will be going the 110v option I will be buying R20 etc modules. I was surprised that they were $450.00 a piece and since they are doubles circuiting them will be problematic. I wish they made just one side a relay. ... The future theater may have more straight AC power.


It sounds like plans are in the works to upgrade your Sensor Classic or Sensor+ dimmer rack (s) to Sensor3 (and I would question whether the expense of this upgrade can be justified), in which case some ThruPower modules would provide the flexibility you seek.


len said:


> Other options:
> Buy a combo distro and dimmer rack (Applied makes them to order, among others) and sell a dimmer rack or two.


Replacing ETC Sensor dimmers with those from Applied Electronics? Not sure I see the wisdom in that scenario.


lightguywcl said:


> ... I made several relay dimmers for a nearby theater in a cd80 rack. Those are easy to work on. In this age of moving lights. The future theater may have more straight AC power.


Let's not talk about modifying the dimmers in a CD80 rack, okay?


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## RonHebbard (Jul 17, 2013)

lightguywcl said:


> In this age of moving lights. The future theater may have more straight AC power.


The newly built venues I've worked on most recently used the same theatrical lighting and rigging consultants out of NYC, NY.
DMX controlled relays powered receptacles throughout the venues for their 'wiggle light' power; 48 - 20 amp single pole breakers and relays for 120 VAC receptacles plus 48 - 20 amp double pole common trip breakers and double pole relays for 208 volt receptacles. In my area of Canada this appears to be where things are currently, pardon the accidental pun, at. 
As you wrote, more and more straight, non-dimmed, DMX controllably switched power.

Toodleoo!
Ron Hebbard


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## lightguywcl (Jul 17, 2013)

Thank you for the info I will talk to the rep to see what they can do for me for ML power. I am sure this is starting to be a common question.


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## sk8rsdad (Jul 17, 2013)

RonHebbard said:


> Hello "dad"!
> (I far prefer forums where folks use their real names like Steve Terry.)


I prefer otherwise. I don't work in entertainment and would prefer to make it just a tiny bit harder for others to stitch my life story together from things I have published on the internet. Now where did I leave my tinfoil hat?

FWIW, there's no way to confirm that Steve Terry really IS Steve Terry. It could be a Nigerian prince posting via a proxy server in Middleton. t doesn't matter though because whoever is posting as Steve Terry is providing really good advice.


RonHebbard said:


> I believe I've caught you in a minor typo that ought to be made crystal clear to the OP.
> "In a 208V circuit provided by a 3-phase Wye (Y) system, there is no neutral."



I think your correction may have contributed more confusion than clarification. It certainly clouds the intent behind my post.

Perhaps I should have phrased it as "in a 208V circuit in a Y system, the neutral does not participate." But then I would have had to say something about how none of the legs were bonded to ground because that bonding happens elsewhere. And then I would have had to talk about Tesla, Westinghouse, and Edison and all those other things that really only he understood about polyphase power and most of the rest of us muddle through in order to pass an electrical engineering exam.


RonHebbard said:


> A delta sourced system would have no neutral.



In a Delta system, one of the legs might be bonded to ground and hence be considered a neutral. Assuming such a bond exists there's a chance a single-pole circuit breaker would actually de-energize the circuit. It would still be silly to use multiple single-phase breakers to de-energize it.


RonHebbard said:


> Another possible misunderstanding for the OP.
> "Since neither leg in a 208V circuit is bonded to ground, a common double-pole circuit breaker"
> 
> I suspect you meant to type 'a double-pole common trip circuit breaker', the trip being common rather than the breaker.



I yield to your pedantry. You are, of course, correct. The breakers are quite common though. I can lay my hands on one with very little effort.


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## lightguywcl (Jul 17, 2013)

> Under your previous scheme, you were willing to sacrifice 24 channels of dimming to gain 12x L6-20 outlets. Now you're concerned about having to swap modules in multiples of two?



Not sure yet I will let you know when I get back to the theater. I just know that when I stick a R20 module in the numbers may not be next to each other. It is a concern until I figure it out. 


> It sounds like plans are in the works to upgrade your Sensor Classic or Sensor+ dimmer rack (s) to Sensor3 (and I wold question whether the expense of this upgrade can be justified), in which case some ThruPower modules would provide the flexibility you seek.



I know for a fact that we are switching out our unison system to a new paradigm system. At the time he inspected the unison system he looked at our dimmers. He said that the ECM modules were being phased out and that it would be difficult to get them repaired in the future. I know that was not a pressing need. Because of how our budget was my TD thought it might be better to do it now since we were going to have to do it eventually. I will ask tomorrow if we are going to do it. Why don't you think the upgrade can be justified?


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## len (Jul 17, 2013)

derekleffew said:


> Replacing ETC Sensor dimmers with those from Applied Electronics? Not sure I see the wisdom in that scenario.



I meant buy a whole new rack, with some dimmers, and some distro circuits. Something like the photo, but configured the way the OP needs it. RACK SYSTEMS | *Applied Electronics Sell one of the old dimmer racks to recoup some of the expense. I don't know if ETC makes them but it wouldn't surprise me if they did. I didn't mean to imply that one should take parts from Applied and try to jam them into an ETC product.


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## RonHebbard (Jul 18, 2013)

Hello again "dad"!

I've no experience and/or expertise when it comes to tinfoil haberdashery, 'nough said.

There is a world other than on the net, I've heard. I believe a call to Steve Terry could provide proof if required/desired and I heartily concur with your assessment of his advice on this forum and elsewhere. I suspect most Nigerian Princes would have giveaway accents, again, 'nough said.

Delta and Wye systems, grounded conductors and what constitutes a neutral; far more than 'nough said and I trust you did well with your electrical engineering exam. I'm not personally aware of any power distribution situation where the common point of a Wye secondary is legally permitted to operate un-grounded but that's just me and I'm entitled to my wrong opinions. I believe the grounded common point always "participates" even though it's not always brought out from the transformer's enclosure.

Let me get back to upgrading my pedantry skills, perhaps, sometime prior to my expiration, I may achieve a passing grade on my pedantry exam. ;^)

Take care Sir!

Toodleoo!
Ron Hebbard


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## josh88 (Jul 18, 2013)

lightguywcl said:


> He said that the ECM modules were being phased out and that it would be difficult to get them repaired in the future.



I'm on a classic CEM and have had no problem with repairs. ETC has a great support system and despite the fact that I've missed out on sensor+ and sensor3 I'm still fine if something goes wrong. worst case scenario you upgrade if it ever failed in the future, but there are systems that have been running far longer than mine without issue. I'd agree that you don't really need to update it. If it aint broke don't fix it, and if it does break you should be able to pick up a new sensor3 brain quick without much difficulty. To me its an unneeded expense that would be much better spent getting the distro you need since that is a more pressing issue.


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## Wood4321 (Jul 18, 2013)

lightguywcl said:


> Interesting idea I will talk to the people that will be upgrading the dimmer racks to see how much it would be. Now that I will be going the 110v option I will be buying R20 etc modules. I was surprised that they were $450.00 a piece and since they are doubles circuiting them will be problematic. I wish they made just one side a relay. I made several relay dimmers for a nearby theater in a cd80 rack. Those are easy to work on. In this age of moving lights. The future theater may have more straight AC power.



I would not go with R20s. Go with CC20 modules instead. 
They are much cheaper, and will prevent anyone from accidentally killing power to your moving lights from the console.


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## sk8rsdad (Jul 18, 2013)

lightguywcl said:


> I wish they made just one side a relay.


Replace your Sensor racks with Sensor3 racks and install ThruPower modules for flexibility. It's basically a D20/R20 combo. This still won't give you 208V but you can turn any 120V channel into a relay on a whim.

Of course, doing this will eat up all the money you had for MLs but that would solve the 208v problem.


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## STEVETERRY (Jul 18, 2013)

sk8rsdad said:


> Replace your Sensor racks with Sensor3 racks and install ThruPower modules for flexibility. It's basically a D20/R20 combo. This still won't give you 208V but you can turn any 120V channel into a relay on a whim.
> 
> Of course, doing this will eat up all the money you had for MLs but that would solve the 208v problem.



You don't have to replace the racks, just retrofit CEM3 and its new backplane in order to enable use of ThruPower modules.

ST


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## tdrga (Jul 18, 2013)

STEVETERRY said:


> You don't have to replace the racks, just retrofit CEM3 and its new backplane in order to enable use of ThruPower modules.
> 
> ST



I thought I read that the ThruPower modules would work in pre-CEM3 racks by using the manual override switch on the module. No remote switching, but still the ability to have one dimmer and one constant circuit in a module.

-Todd


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## HansH (Jul 19, 2013)

tdrga said:


> I thought I read that the ThruPower modules would work in pre-CEM3 racks by using the manual override switch on the module. No remote switching, but still the ability to have one dimmer and one constant circuit in a module.
> 
> -Todd



The limitation is in the control module, not the rack enclosure itself. Once a Sensor Classic or Sensor+ rack has been retrofitted with a CEM (and backplane and assorted small things that are in the kit), you are able to use all the features of the ThruPower module.

Edit: Todd, I see what you're getting at now...


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## sk8rsdad (Jul 19, 2013)

HansH said:


> The limitation is in the control module, not the rack enclosure itself. Once a Sensor Classic or Sensor+ rack has been retrofitted with a CEM (and backplane and assorted small things that are in the kit), you are able to use all the features of the ThruPower module.



Can a rack be retrofitted with AF cards in the field or does it need a new wiring harness?


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## HansH (Jul 19, 2013)

sk8rsdad said:


> Can a rack be retrofitted with AF cards in the field or does it need a new wiring harness?



It _*can*_ be retrofitted with AF cards, but the dimmer modules would need to be AF modules (D20AF, R20AF, etc...). Otherwise, the AF cards wouldn't give you any additional advantage.


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## DavidNorth (Jul 19, 2013)

tdrga said:


> I thought I read that the ThruPower modules would work in pre-CEM3 racks by using the manual override switch on the module. No remote switching, but still the ability to have one dimmer and one constant circuit in a module.
> 
> -Todd



That is correct.


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## Chris15 (Jul 20, 2013)

For the academic side of this discussion, let's talk about circuit breaker grading...

Generally speaking 2x is the minimum difference in protective device ratings to have a reasonable chance of the downstream most device being the one that trips.
So 20/15 = 1.3x = anyone's guess which one will trip on a fault...


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## RonHebbard (Jul 20, 2013)

Chris15 said:


> For the academic side of this discussion, let's talk about circuit breaker grading...
> 
> Generally speaking 2x is the minimum difference in protective device ratings to have a reasonable chance of the downstream most device being the one that trips.
> So 20/15 = 1.3x = anyone's guess which one will trip on a fault...



Hello Mr. 15;

Much, much more to consider, I guess it depends somewhat upon who's general is speaking.

Types of breakers; thermal trip, magnetic trip, ultra fast response, fast or intentionally slower/lagging.
Breakers designed to protect SCR's, TRIAC's, IGBT's.
Breakers intended to power motors, ignoring starting currents for a specified period of time.

Are both breakers passing the same load and only the same load, no additional loads on the larger breaker?
Are both breakers of the same basic type / classification?

Example: A 3P200 amp breaker supplying a three phase 200 amp panel may trip before a 1P15 if one or more phases of the panel are at 180, or more, amps when a heavy load, a dead short for instance, is suddenly applied to a 1P15 that was idling away at a couple of amps prior to the arrival of the dead short.
I'd be suspicious of any such generalisations.

Toodleoo!
Ron Hebbard


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## TimMiller (Jul 20, 2013)

Here is one thing with ETC products, no matter how old they are (even if they were made by lighting methods, before ETC bought them out) ETC still supports the product and will help you get it working again. The whole design from the beginning of the sensor rack was to be modular to support module swapping and upgrades. Also beware of sales guys and consultants they love to sell you things you never know you needed and in actualitiy will ever need. There are lots of original CEM's out there working without any issues and will continue to for at least another 20+ years. Personally when I install movers we power them several ways. Connect a portable power distro to a company switch and run cable, install a panel board "breaker box" in the dimmer or electrical room and run conduit, sometimes they have extra conduit run which really drops expense, or what most schools like are 120v movers connected to cc modules then they can leave them off until they need them so they do not have to worry about students playing with them.


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