Running Power for portable dimmers

[cbrandt]

Just a warning. While it is safely within code, I have had more than one disagreement with a fire marshal about using those short leads. Just check with them first, maybe get them to check the code themselves, so that they are satisfied. Nothing worse than having to call your local shop and get a rushed in disconnect before curtains open.

 

[tdrga]

(2) The supply conductors shall terminate in a single overcurrent protective device that limits the load to the ampacity of the supply conductors. This single overcurrent device shall be permitted to supply additional overcurrent devices on its load side.

Would the particular dimmer pack in question fulfill this requirement? It does not have a main OCPD (breaker).

- Todd

Sent from a mobile device.

 

[SteveB]

Would the particular dimmer pack in question fulfill this requirement? It does not have a main OCPD (breaker).

- Todd

Sent from a mobile device.

Not as I understand it. The "packs" do not have main breakers. You have to move up to the touring racks, 48 or 96 dimmer versions, before you get a main breaker in the unit. Thus the recommendations for a separate power distro., or alternatives to the OCPD sizing at the company switch.

 

[JD]

Would the particular dimmer pack in question fulfill this requirement? It does not have a main OCPD (breaker).

- Todd

Sent from a mobile device.

The only time this comes into play is if you want to downsize the feeder. If your rack is sitting 5 feet from the switch, and you use a full size feeder, then you are good to go. (If it is only a few feet away, then that will also be your cheapest option.) If on the other hand it is 50 or 100 feet away, then five legs of 4/0 can get very expensive.

 

[ethelirene]

Sorry. I meant to reply with quote:

"1. . The dimmer pack may operate on either 3-phase, 4-wire + ground, 120/208V, 50/60Hz AC or 1-phase, 3-wire + ground, 120/240V, 50 or 60Hz, AC
at an amperage sufficient to power the pack.

The NEC is setup to prevent fire & personal injury
You have a dimmer that requires a 160A service. You need over-current protection closer to the 160A rating to be safe.
If there were a short or over-current say 200A the 400A fuses wouldn’t care but your feeder cables would."

I can't make best recommendation without an idea if: this is a one time or infrequent set up or if you will use this regularly, say at least two events per year; and what kind of load do you anticipate - two 575s per dimmer or less or more?

I think the suggestion that the rack is rated for 400 amp feed should be verified but a set of feeders for that is the easiest and least expensive and per code. But if using often and especially if a new feeds in someone else's budget thana dedicated receptacle or hard wiring the rack is not a bad choice - tapping off the co sw feed or other. I would be concerned about distribute back to rack and noise. No doubt installing in a separate room and installing a permanent distro would be best but most expensive. In which case 100 or 125 amp 3 pole is probably fine but tell us how you think you'll loa it.

The plan right now is to use it 3-7 times a year. It would be 5-10 feet from the co sw. The only times we really use sidelight is for department dance concerts and touring dance companies with recorded music. Load could be as much as (2) 750s per, though I was attracted to this pack as it can switch to non-dim for led, which is my next big push.

 

[STEVETERRY]

Would the particular dimmer pack in question fulfill this requirement? It does not have a main OCPD (breaker).

- Todd

Sent from a mobile device.

Unfortunately, no.

ST

 

[SteveB]

er, though I was attracted to this pack as it can switch to non-dim for led, which is my next big push.

Using relays - correct ?.

Dimmers in 'Non-dim" mode are not a good power source for "other then incandescent" loads and though you can get away with it for some loads - a fan, or gobo rotator, I would not be powering LED's this way. Non dim mode still has a distorted sine wave and can play havoc on electronic devices.

The alternatives would be relays or constant breaker modules that swap out for the dimmers (in paired circuits).

 

[JD]

Dimmers in 'Non-dim" mode are not a good power source for "other then incandescent" loads and though you can get away with it for some loads - a fan, or gobo rotator, I would not be powering LED's this way. Non dim mode still has a distorted sine wave and can play havoc on electronic devices.

Somehow, this needs to be better communicated as this (or another variant of the same) keeps appearing in thread after thread after thread.

When a dimmer module is switched into non-dim mode, the firing circuit in the SSR must still develop enough forward voltage to turn on the SSR. The result is a flat line after the zero-volt waveform cross. In other words, NOT a sine wave. Some electronic equipment may not have a problem with this, but your safer bet is to obey "Murphy's Law." Anything that is waveform dependent will have problems.

The only true "non-dim" circuit either contains mechanical relays or no switching mechanism whatsoever (outside of a circuit breaker.)

 

[BillConnerFASTC]

The plan right now is to use it 3-7 times a year. It would be 5-10 feet from the co sw. The only times we really use sidelight is for department dance concerts and touring dance companies with recorded music. Load could be as much as (2) 750s per, though I was attracted to this pack as it can switch to non-dim for led, which is my next big push.

That often - install it with it's own feed. Better off with a Sensor install rack than a portable IMHO. And put it in a room that has some noise isolation from stage. Look at cost of a bigger rack even if you populate half with air flow modules now. And just get a big plug box with 24 (or 48) receptacles on it - or perhaps two with circuits split stage left and right - or overhead if that makes sense. Tap feed from co sw if you want - 125 or 150 amp breaker right there next to switch. This is not a once in a while think where you want that much portable cable all over the place and it won't be many shows before you get complaints about fan noise.

 

[ethelirene]

You have all been fabulous! Thanks!

 

[tdrga]

The only time this comes into play is if you want to downsize the feeder.

I should have indicated that I was "leading the witness" with my earlier question - it seemed that the thread was heading towards suggesting that downsizing the feeder for that dimmer pack was okay without an appropriate OCPD.

-Todd
Sent from a mobile device.

 

[BobHealey]

Not meaning to get off topic here, but can someone tell me why there are places for padlocks on the green, red, and blue outlets? Wouldn't it make more sense to have the locks on the black, red, and blue outlets?

Its a feature of the panel. There are mechanical interlocks in there that prevent covers from being opened unless there is a cable connected to the immediate left of the cover in question. Ground can always be opened, as it is the first connected. In addition, once a cable is inserted, there is a mechanical interlock to prevent the cable to its left from being removed before it is.

If you don't want anything connected, you padlock green closed. If you are only using 1 phase with neutral, you padlock red, which also disables blue. If using just black and red, lock blue.

If you remove the plastic shells, you get standard camlocs with one major exception. Ground and neutral are the same gender as the three hot phases, relying on the unique keying of the plastic shells to keep the phases, ground, and neutral straight. Intermating with standard camlocs is therefore a task best left vague.

 

[Wood4321]

Its a feature of the panel. There are mechanical interlocks in there that prevent covers from being opened unless there is a cable connected to the immediate right of the cover in question. Ground can always be opened, as it is the first connected. In addition, once a cable is inserted, there is a mechanical interlock to prevent the cable to its left from being removed before it is.

If you don't want anything connected, you padlock green closed. If you are only using 1 phase with neutral, you padlock red, which also disables blue. If using just black and red, lock blue.

If you remove the plastic shells, you get standard camlocs with one major exception. Ground and neutral are the same gender as the three hot phases, relying on the unique keying of the plastic shells to keep the phases, ground, and neutral straight. Intermating with standard camlocs is therefore a task best left vague.

One thing I would mention is that, when I was touring, I ran across these panels often. However, I have yet to find one in working order. Every one I have seen has either been permanently unlocked, using the posi-lock rings, or has had the locking pins broken off. Great idea, but poor implementation.

In my honest opinion, I actually like the Power lock style connector much better than Cam/posi, but no chance of it ever taking over here in the US...