Dimmer Doubling/120 volt devices (ETC/Sensor)

[dukeofmuffins]

All that is visible in the catwalk rows are the black boxes with pigtails. They connect to the S4s hanging up there (60ish of them)

The stage has 2 fly bars of PARnels, using the same 77v bulb (30 of those).

There are no visible doublers. All of the drop boxes are connected to conduit which presumably works it way back to the dimmers.

Well I'll be back there in a week to handle their talent show, I'll try and find time to unscrew one of those box panels and peek inside. That's the only place they could be, hardwired or not. I'll take some pics as well.

 

[xander]

Out of curiosity, what kind of connectors are on your pigtails and S4 caps?

 

[dukeofmuffins]

Stage Pin connectors (3 pins) all around. Lights, strips, floor pockets, everything.

 

[xander]

That's disconcerting. If everything you are saying is true, I don't see how this could be an authorized ETC install. ETC insists on L5-15 connectors so that it is harder to plug a 120v load into a doubler. IF everything in the entire building was doubled and using 77v lamps it would be one thing (I would say still not a good idea), but you said you have other instruments like strip lights running on 120v. Everything being 2P&G sounds like you are asking for trouble.

 

[shiben]

That's disconcerting. If everything you are saying is true, I don't see how this could be an authorized ETC install. ETC insists on L5-15 connectors so that it is harder to plug a 120v load into a doubler. IF everything in the entire building was doubled and using 77v lamps it would be one thing (I would say still not a good idea), but you said you have other instruments like strip lights running on 120v. Everything being 2P&G sounds like you are asking for trouble.

I agree with this. My guess is that its not all legit, especially if there are actually doublers in the wall soemwhere. Now, its also possible that someone set it to on thinking it sounded like a good idea, and then never bothered to put in doublers.

 

[ScottT]

I agree with this. My guess is that its not all legit, especially if there are actually doublers in the wall soemwhere. Now, its also possible that someone set it to on thinking it sounded like a good idea, and then never bothered to put in doublers.

Wouldn't doublers be considered a "temporary" install and therefore shouldn't be used as such?

 

[dukeofmuffins]

Alright I'm packing my multimeter next week as well. I'm going to confirm all of this.

I'm waiting to hear back from an old teacher about the designer of the system. I know it was a third party contractor (will get that name too). Does ETC ever do installs themselves?

I love how this has sparked so many questions! If anything I hope to figure out exactly whats doubled and whats not, so the plugs could clearly be labelled. The school is relying more and more on students handling ALL aspects of lighting. Even with liability issues they often don't have a choice. I'd like to clarify this so future users don't destroy any of the bulbs we have, or cause fires, etc.

 

[MNicolai]

Alright I'm packing my multimeter next week as well. I'm going to confirm all of this.

I'm waiting to hear back from an old teacher about the designer of the system. I know it was a third party contractor (will get that name too). Does ETC ever do installs themselves?

I love how this has sparked so many questions! If anything I hope to figure out exactly whats doubled and whats not, so the plugs could clearly be labelled. The school is relying more and more on students handling ALL aspects of lighting. Even with liability issues they often don't have a choice. I'd like to clarify this so future users don't destroy any of the bulbs we have, or cause fires, etc.

It varies. ETC is more closely involved with large, unique, and/or custom installs. Turn-key basic systems installs usually fly in more under the radar, but ETC retains as-built drawings on almost every system they turn on. For that matter, an ETC-trained service tech is required to sign off on dimmer rack installs before the systems can go hot, and as I recall, a service tech technically becomes an ETC employee for the duration of time they spend installing systems.

Unless the doublers were an add after the initial install, ETC should still have drawings of your facility showing how the system is arranged. If they were added after-the-fact, there may or may not be a paper-trail describing how the system was setup.

You can always call Tech Services @ 1.800.444.8825 and someone can tell you what was part of your system when it was installed, and if the doublers were an add after-the-fact, they can probably still talk you through figuring out how exactly the doublers were implemented into your system and what the process would be for removing them as-needed.

 

[SteveB]

It's beginning to sound like at one time the system had, or was supposed to have DD's but possibly got removed ?, or never purchased ?, but possibly the 77v lamps came and were installed anyway ? Possibly the lamps always look dim ?. Ask yourself how many custodians know a 77v HPL from a 120 ?.

Just a thought

Sent from my Android Incredible

 

[JD]

I don't think a 77 volt lamp would last one second at 120 volts. If the fixtures have 77s in them, then those DD modules are somewhere!

 

[DuckJordan]

I don't think a 77 volt lamp would last one second at 120 volts. If the fixtures have 77s in them, then those DD modules are somewhere!

I'd have to agree they would most likely catastrophically fail within 10 seconds of being lamped on.

 

[Footer]

I'd have to agree they would most likely catastrophically fail within 10 seconds of being lamped on.

Not even 10 seconds. They instantly blow. This is why you are supposed to have twistlock connectors on all basecaps for the 77v lamp caps so it is impossible to plug a 77v lamp into a 120v outlet. Now, I have seen more then one venue that simply converted the dimmer doublers over to stagepin or made twist to stagepin adapters. In these venues, you have to cleary mark all dimmer 77v basecaps. Even with a good system in place, it is pretty common to hear lamps blow when during ring out.

 

[MNicolai]

Not even 10 seconds. They instantly blow. This is why you are supposed to have twistlock connectors on all basecaps for the 77v lamp caps so it is impossible to plug a 77v lamp into a 120v outlet. Now, I have seen more then one venue that simply converted the dimmer doublers over to stagepin or made twist to stagepin adapters. In these venues, you have to cleary mark all dimmer 77v basecaps. Even with a good system in place, it is pretty common to hear lamps blow when during ring out.

It's worth noting that using anything other than 2P&G or L5-20 male connectors on the source side and L5-15 female connectors on the load side voids the UL listing. As per the user manual:

C A U T I O N : Dimmer Doublers and Source Four fixtures are UL Listed as an integrated system
using the connectors indicated in this manual. They are not UL Listed when used
with any other connector.

Maybe STEVETERRY can comment on whether or not the UL listing is maintained if a dimmer doubler is hard-wired on the source side.

 

[SteveB]

Not even 10 seconds. They instantly blow. This is why you are supposed to have twistlock connectors on all basecaps for the 77v lamp caps so it is impossible to plug a 77v lamp into a 120v outlet. Now, I have seen more then one venue that simply converted the dimmer doublers over to stagepin or made twist to stagepin adapters. In these venues, you have to cleary mark all dimmer 77v basecaps. Even with a good system in place, it is pretty common to hear lamps blow when during ring out.

I've never used DD stuff except as part of a tour rig, so have no idea how long a lamp runs on 120, so not surprised it goes Jimi. Remember that the OP hasn't stated that any of this 77v stuff is actually working !. Wouldn't surprise me if the custodians took away the DD's and poof went the lamps, especially given everything as 2P&G, which is a major problem.

 

[STEVETERRY]

It's worth noting that using anything other than 2P&G or L5-20 male connectors on the source side and L5-15 female connectors on the load side voids the UL listing. As per the user manual:



Maybe STEVETERRY can comment on whether or not the UL listing is maintained if a dimmer doubler is hard-wired on the source side.

No, it is not.

ST

 

[icewolf08]

There are two really fast ways to figure out what is going on here. First, open up a fixture and actually confirm that it is running a 77v lamp. Could quite simply be a lip of the tongue having meant to say 750w.... Second, check the configuration in the CEM in the rack to see if DD is enabled for any of the dimmers.

Unless the system was installed and commissioned by a non-ETC dealer and technician then it should have been done correctly. If DD was enabled, then the doublers should exist in the code-compliant form, and the fixtures would have the appropriate connector. If they don't exist, it is a fair bet that the system is set up for standard dimming. Also, given the body of evidence the OP has given, like having fixtures that work that are not Source 4s, it is probably safe to assume that the system is set up for standard dimming. I would check these things before we continue to toss out ideas based on incomplete information.

 

[bdkdesigns]

I have only used them once. The venue swapped out the dimmer doubler L5-20's with 2P&G with bright red cap covers. Once an instrument went to 77v, it too had the cover replaced with a bright red one until it was swapped back.

Out of curiosity, would anything happen if they had 77v lamps and changed the CEM to say that dimmer doubling was enabled on a circuit without actually using the doubler? If it would still work with that one lamp, I wouldn't put it past a school to have heard somewhere "Dimmer Doubling saves money on an install"......and stopped reading there.

I know that personally, a third party contractor with no theatre experience initially put the specs on my new system. I initially told them that I was concerned about the process in my interview when they stated that they were not sure what was going on with the renovation. This was concerning since the install was supposed to be happening at that moment of time. Luckily they had an illegal bid process and had to start over and fixed a lot of things (as well as switching from Strand to ETC). Funny story, I have never seen ETC drawing for my space. Even during the install in the demo stage, they had the original Strand drawings and said "we are just simply switching from Strand to ETC so those differences don't matter". Luckily the people with those drawings were not the same people who installed the racks.

 

[Footer]

Out of curiosity, would anything happen if they had 77v lamps and changed the CEM to say that dimmer doubling was enabled on a circuit without actually using the doubler? If it would still work with that one lamp, I wouldn't put it past a school to have heard somewhere "Dimmer Doubling saves money on an install"......and stopped reading there.

It will still blow the lamp. The dimmer still puts out the full voltage, the voltage it just chopped in a weird way. You get an even weirder looking light if you have a dimmer set up for doubling that does not have a doubler and a 115v lamp on it. It give it this odd flicker and never gets all the way up to full.

 

[jglodeklights]

I agree with IceWolf, we should wait until all the evidence is gathered.

I would, however, not necessarily be surprised if not all the circuits in the building were doubled, while most of them are. Again, third party installations can lead to some strange things, especially when the third party does not do their homework.

The now torn down auditorium of the high school I work with had their first electric refitted into a pipe with a raceway versus the 40 foot long strip light pipe as originally installed. The retrofit resulted in some very odd hardwired twoferring in the raceway. Additionally, the halogen house lights were placed in a group of 6 of the dimmers randomly located, rather than starting at the beginning or end of the circuits. And despite having a rack of 96 Strand dimmers, I could only find circuits up to 84 or 90.

In the new auditorium they are building, everything was specified by the consultant to have twist lock connectors. When I asked why, he stated it was so the TV studio and theaters (auditorium and black box) can use the same lights, and so we can do dimmer doubling. However, no dimmer doublers were specified in the package, nor was any twist lock cable. He had obviously failed to do any form of research on who the end user is. The high school rents from one small local rental shop in which all units are stage pin, all 40 units we are carrying over (and need, the new package isn't large enough for the shows they do) are stage pin, and all our existing cable is stage pin. This same person also specified a 14 inch LCD monitor for our Express lighting console that is already equipped with a 15 inch monitor, and an additional Lycian Midget spotlight when they haven't used the one they have now in about 5 years (they use S4's with irises on the catwalk).

Thus, as I said, I wouldn't be surprised.

 

[JD]

Ahhhh... There is actually one scenario where the doublers could be missing and the lamps not blowing, but its a stretch:

In theory, if doubling was enabled and all of the "B" channels were parked at zero, the 77 volt lamps would only see one-half the waveform from the SSR, as only 1/2 of the SSR was being fired, and the lamp would not blow. Of course, if any of the "B" channels were brought up at the same time as the "A" channel was up, POP!

The purpose of the fixture-end modules is to block 1/2 of the AC waveform to each of the fixtures. (Fixture "A" sees one polarity, fixture "B" sees the other.) A pretty rock solid idea, as even it the doubler module was plugged into a non-dim outlet, each lamp would still only see one side, and both would simply come on full brightness. This is why the input to the module is Stage pin. (Doesn't matter if it gets patched wrong, the lamps are safe.) The same is NOT true on the lamp side of the module. You could plug a 120v fixture into it and it would just be dim, but plug a 77 volt fixture into 120 volts and watch your wallet shrink. Thus, the non-standard connectors.

Outside of the highly unlikely scenario I started off with, there are only two possibilities:

1) The fixtures actually have 120 volt lamps in them, any your stock was a goof.

2) Someone did something naughty and built the modules into a hidden location.