Control/Dimming Company switch questions

[sweetssounds]

Has anyone seen a 225amp or 150 amp company switch with cam lock outs ?

I am helping to advice the retrofit of a new event center. The space used to be a temporary library while our new one is being built. But back to specifics. The main switch to the building is a 800 amp breaker @ 480v it has LOTS of unused power which we are hoping to use for lighting and sound. What is listed on the breakers is that there is a 400amp breaker, a 225amp breaker, and a 150amp breaker. Each of these is listed a three phase but also listed as 220v? from my understanding 3 phase is actually 208V? so im a little confused?? Maybe I have something wrong.

There is a electrical contractor working on the project as well but they apparently have not worked with company switches so i have to give them as much information as possible. Are there Company switches in 225amp or 150amp increments? or will i have to use 100 amp and 200amp and waste the extra amperage? Or will the extra amperage be lost in voltage drop if it is in deep 220v since it has to be 208v?


sorry if these questions make no sense!!

 

[tjrobb]

Well, 220V could be wild leg delta or 218Y127 3phase. We have the latter here. As for the 225A, you could install a switch with an internal 200A breaker and save yourself a headache, the feed cables would still need to be 225A though.

Reread the post, are you looking at 480V breakers or 120V breakers? My original answers assumed 120V.

 

[JD]

Has anyone seen a 225amp or 150 amp company switch with cam lock outs ?

I am helping to advice the retrofit of a new event center. The space used to be a temporary library while our new one is being built. But back to specifics. The main switch to the building is a 800 amp breaker @ 480v it has LOTS of unused power which we are hoping to use for lighting and sound.

Hold the phone on this one....
480 volts? If this is true, then your building may be laid out with local transformers servicing local panels. I have run into this a number of times where the main building distribution was 480 volts, then small "dry" transformers were located next to sub-panels that took it down to 120 volt 3 phase Wye. Often, these local transformers are no where nears the size needed to run a lighting system.

The philosophy behind this one was to cut down on the copper size on extended runs to different areas of the building. If this is the case, then you may have a bigger project then you thought coming up with power.

Regarding company switches: The 400 amp Cam is the standard size to use even if you are only using a fraction of that capacity. The switch's are de-rated by using smaller fuses, but to keep compatibility with the rest of the world, use E1016 series Cam-Locs.

 

[jhochb]

or will i have to use 100 amp and 200amp and waste the extra amperage? Or will the extra amperage be lost in voltage drop if it is in deep 220v since it has to be 208v?

Good Morning Sweetsounds

I see this a lot here.

You’re not wasting anything.
VOLTAGE is a set quantity. It is determined by the tap selected at the TRANSFORMER. That could be 120/208, 277/480, 345/600 for a 3 phase system. Or 120/240 for a single phase system here in the states
AMPERAGE is taken by the LOAD. If it’s not needed it doesn’t go to waste ,it just isn’t used. but it's there if you need it.

Like JD said have your electrician look at your service. Explain that a company switch is just a high current outlet with a switch & maybe 3 fuses. He’ll get it.


Sorry if this sounds like I'm slamming anyone
That's not my intent.
This forum is for an exchange of information & this kind of question SHOULD be asked if you don't know the answer.

 

[sweetssounds]

Thank you for your answers its very helpful

The 800amp main is 480v then the larger breakers like the ones i mentioned are listed at 240V (edit sorry for the typo i know it changes a lot) there are also other breakers like 20amp which are 120v

The reason for the confusion is that i sent them the brochure for LEX Power Gate company switch just to give them and idea of what it is. On that there are only listed 400amp, 200amp and 100amp company switches. The electrician is confused because on my mock up plans i listed the company switches as the amps listed at the breakers (specifically the 225amp and 150amp) not the ones offered by LEX. So there asking for which number is correct. Should we just use the 200amp company switch for the 225amp breaker? that 25amps would just be un used or still available "when i need it"? and the same with the 150amp breaker? is there any way to get a 150Amp company switch if that 50amps would be unusable ?


There should be enough power correct? JD had some concerns that it would be 120v and there for not enough but since it is indeed 240V that should be fine?

EDIT: Also the electrician is saying we would need a 225kVA transformer in order to use all 3 switches at the same time? could someone explain why ? shouldn't the breakers already be made to handel that kind of load if they are built in?

 

[JD]

As for information to give him, here's a nice one from Lex:
PowerGATE™ Power Switches: 200 Amp Company Switch | Lex Products

Of course, this is about the best looking one I have seen around, but it is nice to aspire to a good product!

(Seams most of the ones I had to deal with were bent over terminals located in a room half full of water! Such was my luck!)

 

[sweetssounds]

As for information to give him, here's a nice one from Lex:
PowerGATE™ Power Switches: 200 Amp Company Switch | Lex Products

Of course, this is about the best looking one I have seen around, but it is nice to aspire to a good product!

(Seams most of the ones I had to deal with were bent over terminals located in a room half full of water! Such was my luck!)

This was exactly the information i sent them! read my reply above to see where the confusion was

 

[TimMiller]

Transformers are used to step down the voltage. High voltage is used such as 480 so that the amperage drops. When the voltage decreases the amperage increases. He is probably saying you need a transformer to step down the 480 to 120/208. You do not want 120/240 3 phase because then you get a "wild leg" of 208 which has no use except for some 3 phase motors. Show your electrician the company switch (be warned they are not cheap) and tell him you need 120v per leg. Also you do not want to have lighting and sound together especially on the same transformer.

 

[sweetssounds]

Transformers are used to step down the voltage. High voltage is used such as 480 so that the amperage drops. When the voltage decreases the amperage increases. He is probably saying you need a transformer to step down the 480 to 120/208. You do not want 120/240 3 phase because then you get a "wild leg" of 208 which has no use except for some 3 phase motors. Show your electrician the company switch (be warned they are not cheap) and tell him you need 120v per leg. Also you do not want to have lighting and sound together especially on the same transformer.

Thank you for the information I am speaking with them later today. The note about sound and Lighting on different transformers is very helpful. I though difference circuit breakers would have been enough.

 

[TimMiller]

Breakers are nothing more than a fancy switch. Transformers completely isolate their secondary and primary sides from each other. Typically in road houses they have at least 1 if not 2 400amp disconnects for lighting then a 200 amp disconnect for audio. Your actual power consumption will depend upon what equipment you are using. All intelligent rigs will use less power than conventional. If you are using just 20 par cans compared to 200 your loads will vary. You also do not want to max out your loads. All electronic devices have an inrush current which means it will pull more current when it is first turned on than when it is normally running. For example say you have a huge rig running off a generator (you get a good visual from a generator and how loads react) you slowly fade you rig up. The generator will rev up a little to compensate for the load. Now you fade your rig back out generator idles down. Now you bump everything to full. Generator will jump burp out a bunch of smoke and continue running your rig. What I am getting at is overrate what you think you may need. You can always use less power but getting more later on is a small fortune. Even with large mover rigs we stagger strike the lights so that the electrical switch gear does not get hit with a large load all at once.

 

[JD]

Also, remember that the switch must be de-rated by 20%
In other words, a 200 amp switch should not be loaded with a continuous load that is greater than 160 amps. (per leg)

I am more worried about the possible 480 volt main. I think you will find that a transformer the size your electrician spoke of to be in the 5 digit range of pricing. If the mains are 480 volts, than the transformer is NOT optional. Get several quotes on the size needed.

For a 200 amp switch, you would need 200 x 3 x 120 or 72Kva.
I am not up to speed on any capacity/demand changes that could be used to justify adjusting the size of transformer needed. Remember, transformer calculations require you to look at the type and duration of loading.

 

[jhochb]

Good Morning JD

if you look at te LEX page

Product Line
200 Amp Company Switches

Description

The patented Lex Products Company Switch provides a safe and convenient means of supplying temporary power access. The space saving, metal enclosure provides 16 Series Cam-type output. Connections protected by a 100% rated, electronic trip main breaker.

This is a 100% rated switch. no derating is needed
Alot of entertainment grade switchgear is rated this way

Sweetssounds
The breaker ( over current protection ) is there to protect the wiring, not the load.

 

[JD]

This is a 100% rated switch. no derating is needed
Alot of entertainment grade switchgear is rated this way.

Yes, generally breakers on dimmer packs are 100%. In this case Lex is specifying 100% which is great and you are correct.

However, if you do not go with the Lex switch, make sure you check with the manufacturer on their OCPD rating.
Even with the switch being 100%, you will probably be feeding that switch from a conventional breaker in the main or sub panel. That conventional breaker would be de-rated.

To work around this, the main panel breaker would have to be 250 amps and the wiring between the main panel and the switch would have to follow code for 250 amp wiring. At that point, the 200 amp company switch by Lex would be able to provide the full 200 amps per leg.

(250 x 80% = 200)

A footnote for those who may be confused by this issue:
Circuit breakers are rated to handle "real world" conditions. It is unusual for there to be applications where the full capacity of a breaker to be in use in the "real world." Not so in the lighting world! A 20 amp dimmer is considered to be a 2.4kw dimmer (20 amps x 120 volts.) Although dimmer manufacturers recommend that dimmers not be fully loaded due to inrush trips, they do have that steady state capability.
In such applications where real loads are the same as the OCPD (circuit breaker) rating, the NEC requires the load to be de-rated to a maximum continual draw of 80% of the breaker's capacity. This is due to the fact that a conventional breaker will trip if the load is sustained above 80% for a long enough period of time. Many breakers used in switchgear equipment are rated for 100% and do have a special exemption from the NEC.
However: "Buyer Beware" does apply!

 

[JohnD]

Is the reason the lex panel has double neutrals because of triplen harmonics?
Also, is it still necessary to feed audio and lights from seperate transformers? Or is that an old wives tale?
I know that recording studios were installing autotransformers for lighting long after scr/triac dimmers were commonplace.
Is anyone familiar with this book:
Electricity for the Entertainment Electrician & Technician: Richard Cadena: 9780240809953: Amazon.com: Books
Is it the best source for more information or is there something else. Should I instead save up and get the NEC code plus workbook if I wanted to learn more.

 

[derekleffew]

Is the reason the lex panel has double neutrals because of triplen harmonics? ...

Yes. See http://www.controlbooth.com/forums/question-day/8986-why-two-neutral-camlok-inputs.html .

... Also, is it still necessary to feed audio and lights from seperate transformers? Or is that an old wives tale?
I know that recording studios were installing autotransformers for lighting long after scr/triac dimmers were commonplace. ...

Still a good idea. Along with IGRs.

...Is anyone familiar with this book:
Electricity for the Entertainment Electrician & Technician: Richard Cadena: 9780240809953: Amazon.com: Books
Is it the best source for more information or is there something else. Should I instead save up and get the NEC code plus workbook if I wanted to learn more.

While it has many flaws, the Cadena book is the most comprehensive on the topic. Are you studying for the ETCP exam, or just want more information? I'd buy the 2014 NEC first (available ~Sept/Oct 2013), but you'll learn more from EEE&T.

-----

... Are there Company switches in 225amp or 150amp increments? ...

While it would be a custom size from Lex Products or Union Connector, remember that a company switch is just a fused (or breakered) disconnect, with either Lug, Class K Rated s or panel mount E1016 Cam-loks. Any electrical contractor can assemble one from stock parts, albeit without the extra safety features of a manufactured unit. Slap 225A fuses in there and bam!--it's a 225A company switch.

.

 

[JD]

I know that recording studios were installing autotransformers for lighting long after scr/triac dimmers were commonplace.

Autotransformers are sign wave dimmers by nature. As there is no waveform chop, there is very little chance they will interfere with audio equipment. Remember, in a studio setting you are looking for the highest possible signal to noise ratio. The old world of autotransformers is very kind to audio equipment.