Can I get 240V from ETC Sensor rack by combining 2 circuits?

[WFair]

I work in a venue with a Sensor "Classic" rack that has around 100 dimmer circuits on D20 modules. Each circuit is distributed to a single receptacle in a 1-to-1 configuration. We are in the USA, so each circuit is 20A 120V. We have some new temporary (rental) gear coming in that requires a 240V circuit. I know that I could achieve this with a 2-pole breaker in a traditional panelboard, so my question is this: If I put in a CC20 module (constant non-controlled breaker), could I then combine the 2 existing circuits into a 240V at the other end? I know there are a lot of reasons why this might be a bad idea from a long-term/confusion standpoint. This would (obviously) need to be notated and labeled accordingly to avoid safety problems if anyone tried to update anything...but from a purely ELECTRICAL perspective, would it work? I understand the HOW of the wiring to accomplish the receptacle and it is for a short-term (temporary) use and I am the only person at our venue who would ever be anywhere near the wiring, so I am not particularly concerned about anyone messing things up.

 

[danTt]

Ignoring for a second all of the code violations such a thing would cause.

No, a single CC 20 will not provide 240v by combining both circuits on the card. Even assuming you're in a rare split phase house and not on a three phase dimmer rack, both "sides" of the card are on the same phase, so there's no voltage difference between them.

No longer ignoring code violations:
No. Don't do it. Get an electrician to install an appropriate outlet or two, or add a service with camlocks that you can tie a distro into. It'll be much more flexible for future needs

 

[DuckJordan]

I work in a venue with a Sensor "Classic" rack that has around 100 dimmer circuits on D20 modules. Each circuit is distributed to a single receptacle in a 1-to-1 configuration. We are in the USA, so each circuit is 20A 120V. We have some new temporary (rental) gear coming in that requires a 240V circuit. I know that I could achieve this with a 2-pole breaker in a traditional panelboard, so my question is this: If I put in a CC20 module (constant non-controlled breaker), could I then combine the 2 existing circuits into a 240V at the other end? I know there are a lot of reasons why this might be a bad idea from a long-term/confusion standpoint. This would (obviously) need to be notated and labeled accordingly to avoid safety problems if anyone tried to update anything...but from a purely ELECTRICAL perspective, would it work? I understand the HOW of the wiring to accomplish the receptacle and it is for a short-term (temporary) use and I am the only person at our venue who would ever be anywhere near the wiring, so I am not particularly concerned about anyone messing things up.

yeah this is just a hard no, just like a male to male Edison plug is a terrible idea. This is just dangerous.

 

[STEVETERRY]

No, you cannot do this, as the single-pole circuit breakers are not common-trip, since they are physically separated in different modules.

You need portable power distribution to accomplish your goal.

ST

 

[TimMc]

I"ll be the contrarian (Orthodox)..

Go ahead, and stand REALLLY REALLLLY CLOSE to the rack when you energize this whole widowmaker.

If, somehow, the sarcasm escaped you.... this is a really f'in bad idea. People can die, buildings could burn.

 

[danTt]

I"ll be the contrarian (Orthodox)..

Go ahead, and stand REALLLY REALLLLY CLOSE to the rack when you energize this whole widowmaker.

If, somehow, the sarcasm escaped you.... this is a really f'in bad idea. People can die, buildings could burn.

I don't think either of the above would cause mortal issues given the details provided, but I do think thatb scenarios exist and could be easily identified where the fallout of these choices could lead to bad things.

Your advice has the side effect of "no one died, I guess it's okay"

 

[WFair]

No, a single CC 20 will not provide 240v by combining both circuits on the card. Even assuming you're in a rare split phase house and not on a three phase dimmer rack, both "sides" of the card are on the same phase, so there's no voltage difference between them.

No, you cannot do this, as the single-pole circuit breakers are not common-trip, since they are physically separated in different modules.

Great points from both of you.

And to all the others...yes...I know it is a bad idea...I outlined that...I just was trying to find out if it was possible. I will rent a distro to hook up...but unfortunately, my only tie-in for that is about 175-feet away, so I was trying to find a workaround for a one-day event.

Thanks all.

 

[TimMc]

I don't think either of the above would cause mortal issues given the details provided, but I do think thatb scenarios exist and could be easily identified where the fallout of these choices could lead to bad things.

Your advice has the side effect of "no one died, I guess it's okay"

Note the conditional words I used... but this is a bad idea and even if nothing bad happens this time, it remains a bad idea.

 

[DuckJordan]

Great points from both of you.

And to all the others...yes...I know it is a bad idea...I outlined that...I just was trying to find out if it was possible. I will rent a distro to hook up...but unfortunately, my only tie-in for that is about 175-feet away, so I was trying to find a workaround for a one-day event.

Thanks all.

175' of rented feeder is a lot cheaper than a wrongful death suit or a new building.

 

[cbrandt]

Not that I think anyone has missed it, but for anyone reading this in the future. The dangerous thing about these is that they will "work" in that with the right amount of kludging they'll get you the output you expect. But all of the subtle and insidious danger is still there. When you get into a failure mode, all your protection disappears, and new and exciting ways of getting hurt, dying, or burning down your building crop up very quickly.

That's why we all so unequivocally no to anything like this. Many people in the industry have spent a career using solutions like this that "always worked before", and "solved a problem when I didn't have another solution." I'm grateful they're still alive and those venues are still there, but that isn't a standard for whether it is safe.

 

[derekleffew]

No, a single CC 20 will not provide 240v by combining both circuits on the card. ... both "sides" of the card are on the same phase, so there's no voltage difference between them.

But! if you always start with an EVEN number, the next number sequentially will be odd, and on a different phase.

Now ask me how I know, how I need to know that.

Rather than ask, "Will it work?" Ask, "Have you ever..."

EDIT:
Most people, unless they already had them collecting dust on a shelf, would not even bother replacing a D20 with a CC20. Just park the dmmer module at full in the CEM, or at the console, or both. File this under "if you're going to break one rule, why not break them all?"

 

[sk8rsdad]

But! if you always start with an EVEN number, the next number sequentially will be odd, and on a different phase.

I'm having a hard time picturing such a thing working in a standard sensor rack.

AFAIK, there are only 2 locations in the rack where different phases are adjacent. The CEM is in one of those locations. Modules all land on a single phase. As others have stated, it would be a BAD IDEA to make use of this design feature in creative ways.

 

[danTt]

I'm having a hard time picturing such a thing working in a standard sensor rack.

AFAIK, there are only 2 locations in the rack where different phases are adjacent. The CEM is in one of those locations. Modules all land on a single phase. As others have stated, it would be a BAD IDEA to make use of this design feature in creative ways.

View attachment 25360

It's the difference between a "balanced" and a "straight" rack. in a balanced phase setup, sequential even-odd circuit numbers will be on different phases. Consecutive modules are on the same phase, but the numbers are assigned in a distributed fashion.

 

[Footer]

Get an electrician to install a few 240v circuits in a few breaker panels. Its not a big deal to do.

 

[JimmyM]

I'm having a hard time picturing such a thing working in a standard sensor rack.

AFAIK, there are only 2 locations in the rack where different phases are adjacent. The CEM is in one of those locations. Modules all land on a single phase. As others have stated, it would be a BAD IDEA to make use of this design feature in creative ways.

View attachment 25360

Off topic, but to be pedantic the CEM is either in the middle of the B phase in a SR48, and at the bottom the C phase in the SR24 and SR12.

Also, in a 3-phase rack you're only ever going to have 208v, not 240v, not that there is a safe place to make that happen.

 

[jtweigandt]

OK I may be resident jester at the moment.. but the real answer is "Sure you can, but 120V is already enough to kill you"

 

[CraigV]

Just to add yet another reason it would be a bad idea... If only one of the breakers pops, you run the risk of serious damage to the equipment as well.

I was in a similar situation where I had no company switch, only 120v, and needed 240v. As it turned out, there was a firmware update available for the fixtures that let them run on 120v, so I asked the rental shop to change the installed firmware for me. Perhaps a similar update exists for your situation?

But as stated above, it would be best to have the appropriate recepticles installed by a certified electrician rather than doing it in a "show must go on" sort of way.

 

[ship]

Are you sure you only need 240v - and for what? As above even if you did the un-safe connecting of two dimmers of opposing phase, on a normal three phase 120/208v Wye dimmer supply, you will still only get 208v.

Is it ... what you need auto ranging for what voltage?
What is the fixture details?
I have in the past re-lamped fixtures for 120v power including adjusting lamp socket seat height for an an alternate lamp. Otherwise made or rented transformers as needed. Probably cheaper than running a 240v Delta run - assuming available to the theater.

TimMc...

 

[Ravenbar]

I work in a venue with a Sensor "Classic" rack that has around 100 dimmer circuits on D20 modules. Each circuit is distributed to a single receptacle in a 1-to-1 configuration. We are in the USA, so each circuit is 20A 120V. We have some new temporary (rental) gear coming in that requires a 240V circuit. I know that I could achieve this with a 2-pole breaker in a traditional panelboard, so my question is this: If I put in a CC20 module (constant non-controlled breaker), could I then combine the 2 existing circuits into a 240V at the other end? I know there are a lot of reasons why this might be a bad idea from a long-term/confusion standpoint. This would (obviously) need to be notated and labeled accordingly to avoid safety problems if anyone tried to update anything...but from a purely ELECTRICAL perspective, would it work? I understand the HOW of the wiring to accomplish the receptacle and it is for a short-term (temporary) use and I am the only person at our venue who would ever be anywhere near the wiring, so I am not particularly concerned about anyone messing things up.

Depending on the power requirements, they make step up converters to power 240v off of 110. The bigger question is if the rental gear is expecting 50Hz or 60Hz power, as that is different in different parts of the world as well as the voltage.

 

[Jay Ashworth]

Get an electrician to install a few 240v circuits in a few breaker panels. Its not a big deal to do.

We've looked at getting 208/240 receptacles installed on our stage (for an Atomic 3000) and in our adjacent stage shop (for a newer circular saw that requires it), and -- given that the power room is on the other side of the floor, and our college does not have a staff electrician, the informal quotes were *well* up into 4 figures.

It may well be a big deal to do.