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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => AC Power and Grounding => Topic started by: Jason Lucas on November 11, 2013, 12:38:46 AM
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My knowledge of power doesn't go very far beyond standard 15 amp wall sockets and standard NEMA 5-15p connectors.
I know in more professional audio applications they use power distros. Where can I learn some of the basics of what makes up one and how they're hooked up?
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My knowledge of power doesn't go very far beyond standard 15 amp wall sockets and standard NEMA 5-15p connectors.
I know in more professional audio applications they use power distros. Where can I learn some of the basics of what makes up one and how they're hooked up?
Yes, but it takes 2 to 4 years to read it.
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My knowledge of power doesn't go very far beyond standard 15 amp wall sockets and standard NEMA 5-15p connectors.
I know in more professional audio applications they use power distros. Where can I learn some of the basics of what makes up one and how they're hooked up?
Mr. Perry is spot on. I'm still trying to fully understand the NEC from 2005. :-/
A "distro" is, in NEC-speak, a sub-panel. Its line-side connection takes big, high ampacity wire and connects those wires to a bus bar for each hot leg, neutral, and earth ground. The line side of a circuit breaker is connected to 1 or more hot leg buses and the load side is wired to an outlet of some kind (along with the neutral* and ground). It's analogous to the electrical system in your home.
I suggest http://www.amazon.com/Electricity-Entertainment-Electrician-Technician-Richard/dp/0240809955/ref=sr_1_1?ie=UTF8&qid=1384156647&sr=8-1&keywords=richard+cadena
It's not exactly "for dummies" but you'll find it much more useful than readying the National Electrical Code. That comes later...
* some loads do not require a neutral, such as 3 phase motors.
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My knowledge of power doesn't go very far beyond standard 15 amp wall sockets and standard NEMA 5-15p connectors.
I know in more professional audio applications they use power distros. Where can I learn some of the basics of what makes up one and how they're hooked up?
The whole "dummie" thing takes on a new meaning when you can kill people or burn down buildings or destroy lots of expensive equipment.
It is not something you "read", but rather something you learn-from people who know what they are doing.
Fundamentally it is pretty simple-if you understand the basics-but NOT something that should be taken lightly.
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Understood, I'm not trying to do a DIY sub-panel or anything right now, I just want to know more about power distros in pro audio applications, what makes up one, how they're wired, etc.
Our equipment has always simply been plugged into the nearest wall outlet, so we've never used a dedicated distro for audio equipment.
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Understood, I'm not trying to do a DIY sub-panel or anything right now, I just want to know more about power distros in pro audio applications, what makes up one, how they're wired, etc.
Our equipment has always simply been plugged into the nearest wall outlet, so we've never used a dedicated distro for audio equipment.
What we do is build a private electrical distribution system that must meet Code requirements, just like your home or office.
I built my first distro almost 30 years ago so I could play a gig in a converted motorcycle service shop. Lots of NEMA 5-50 for welders and other stuff, so I wired an electric range cord/plug to a 8 space subpanel breaker box, installed the outlets on the side of the box and wired in 20 amp breakers. I think I used a little paperback book from the lumber yard "guide to electricity in the home and on the farm" (or something like that) for guidance. Didn't kill anyone or start any fires, but the only thing about it that would be a violation of Code is the plug & cord set (not listed for the use). It was retired long ago.
Do you have some specific questions about electrical distribution? It's not magic, but it does require a healthy respect for the forces of the energy involved and an absolute commitment to safety.
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What we do is build a private electrical distribution system that must meet Code requirements, just like your home or office.
I built my first distro almost 30 years ago so I could play a gig in a converted motorcycle service shop. Lots of NEMA 5-50 for welders and other stuff, so I wired an electric range cord/plug to a 8 space subpanel breaker box, installed the outlets on the side of the box and wired in 20 amp breakers. I think I used a little paperback book from the lumber yard "guide to electricity in the home and on the farm" (or something like that) for guidance. Didn't kill anyone or start any fires, but the only thing about it that would be a violation of Code is the plug & cord set (not listed for the use). It was retired long ago.
Do you have some specific questions about electrical distribution? It's not magic, but it does require a healthy respect for the forces of the energy involved and an absolute commitment to safety.
I just want to know what a power distro for a pro audio system looks like. What components are involved, and how it's all wired together.
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I just want to know what a power distro for a pro audio system looks like. What components are involved, and how it's all wired together.
You can usually think of a distro as similar to the main breaker panel in your house. A big fat wire comes in, and then thinner wires get sent to each outlet or outlets in the home. The stove and dryer get bigger wires sent to them, as they need more than 15 amps, but pretty much everything else is small circuits. It's the exact same concept for an pro audio distro.
Now, where things get complicated, is that you have to know what your source power is going to be, and how you're going to divide all of that stuff up. A typical home will have single phase power which has 2 legs around neutral. 3 phase power has 3 legs. Ideally, you want to divide your load so each leg has approximately the same load on each. In a 3 phase situation, if 2 legs are loaded, and the third free, there is going to be more current on the neutral line than on either of the legs. If the load is perfectly balanced, nothing flows on the neutral line. Of course, that never happens, and a loss of a neutral line in any multi phase system can cause instant voltage swings that destroy gear. Good times.
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I will say that there is a separate forum for AC Power and grounding and believe this topic should be moved there!
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Distro for dummies is any book someone reads and then believes they can build their own distro without consequences.
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And how do these things fit into all this?
http://www.appliednn.com/e_RS1_pop.php (http://www.appliednn.com/e_RS1_pop.php)
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And how do these things fit into all this?
http://www.appliednn.com/e_RS1_pop.php (http://www.appliednn.com/e_RS1_pop.php)
That would be a portable moving light distro. I can't tell from the photo, but it is probably a 200A (400A?) 3Ø distro, with Edison and Socopex outputs. The back of it has all the circuit breakers and meters, the front has all the connectors, from the 5 wire Cam-Lok to the Edison and Socopex. The Socopex multies are probably 6 20A circuits each (maybe 10A or 15A) and the Edisons are 20A each. There are also some DMX network switches in there.
A sound distro would likely have fewer Socopex and maybe some PowerCon. Sound distros usually top out at 200A, most are less.
Mac
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And how do these things fit into all this?
http://www.appliednn.com/e_RS1_pop.php (http://www.appliednn.com/e_RS1_pop.php)
This distro appears to be a MLD Lighting Distro.
On the right of the picture, there is input CAM LOCK connectors (and thru's as well). They take big power (usually 100-400A) on individual cables (1 cable per leg, neutral, and ground). There is also 'courtesy' power beside that connection for local use (ie, chargers, desk lights, etc)
In this distro (from bottom up, above the camlock connections), it then breaks it down into 8 SOCAPEX connectors of 6 15 or 20A 125/208V circuits, the breakers are on the right of the picture. In addition, it also breaks that cam feed down into 6 15-20A 125V Edison connections. All breakers appear to be on the right.
The top units appear to be DMX splitters.
BRad
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Figures I do a google search and it comes up with a totally different thing. I couldn't actually tell the difference since I don't know what most of those different colored plugs are.
Anyway,
I've heard that it's usually preferred if you have all the audio equipment on its own distro, including FOH. My question is how is that all wired together?
How do you get the FOH board wired into the same distro as the stuff on stage (or even back stage)? What if you wanted to put the entire system on a power sequencer?
Don't worry I'm not trying to do any of this myself, but I'd like to understand how it all works.
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My knowledge of power doesn't go very far beyond standard 15 amp wall sockets and standard NEMA 5-15p connectors.
I know in more professional audio applications they use power distros. Where can I learn some of the basics of what makes up one and how they're hooked up?
Here are a few examples
http://whirlwindusa.com/catalog/power-electrical-distribution/default/power-distro
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Figures I do a google search and it comes up with a totally different thing. I couldn't actually tell the difference since I don't know what most of those different colored plugs are.
Anyway,
I've heard that it's usually preferred if you have all the audio equipment on its own distro, including FOH. My question is how is that all wired together?
How do you get the FOH board wired into the same distro as the stuff on stage (or even back stage)? What if you wanted to put the entire system on a power sequencer?
Don't worry I'm not trying to do any of this myself, but I'd like to understand how it all works.
To keep it simple:
The main power comes into the distro (distribution) panel via large cable and high current connectors.
Then it goes through breakers (just like in your house) and there are various outlets of various current capability and voltage.
Some may be 20A 120V edisons and others may be 50A 240V or three phase outlets or any combination.
Which ones depends on what particular power a particular system may need.
Not every one is the same. They are setup to distribute the power needed (voltage and current) to various aspects of the system-amp racks-backline power-FOH and local outlets for 'whatever".
They are all different because the needs are different. It does not do any good to have a distro that does not "match" your configuration/needs.
When doing a system-the whole system is thought of as a whole.
If you don't know what your specific needs are-then there is no way to know how to "distribute" it.
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I think there is a "Power distro for dummies" handout in the funeral home waiting room.
JR
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Figures I do a google search and it comes up with a totally different thing. I couldn't actually tell the difference since I don't know what most of those different colored plugs are.
From the pic you linked, we'll start on the right rack, bottom to top: CAM-LOK "in" and "thru" with reversed Ground and Neutral. Green=earth ground; White=neutral; Black=hot leg X; Red=hot leg Y; Blue=hot leg Z. Connect in that order, reverse order to disconnect. The lower row of Cams is the inlet, the upper row is the "thru." The connections are bused internally and there is no breaker between the "in" and "thru." Imagine a copper bus bar extending vertically, linking the in and thru. In the left hand rack (the pics are front/back of the same model), the lower 4 rack spaces are occupied by the master breaker that feeds the circuit breakers above it.
Up next, the 2 panels with red Socapex® connectors: Mac and others are correct, these are 208v. connections for moving lights, strobes, etc. That's why they're red. If you look at the other side of the rack, you'll see that the breakers are labeled accordingly and that each circuit has a 2 pole breaker (2 hot legs). The next panel up has a pair of 120v. Socapex connections. The breakers are in the top breaker panel and labeled accordingly. Note they take up less space because each circuit has only 1 hot leg.
At the top are a pair of DMX splitters and a fairly sophisticated voltage, current and line frequency metering system.
Anyway,
I've heard that it's usually preferred if you have all the audio equipment on its own distro, including FOH. My question is how is that all wired together?
Just like plugging it into the wall, except we take all the outlets and put them on a very small wall ;)
How do you get the FOH board wired into the same distro as the stuff on stage (or even back stage)? What if you wanted to put the entire system on a power sequencer?
Portable sound or permanent install? I can count on 1 finger the number of portable systems with sequencers I've encountered. But the answer is "so you can plug it in at the distro, run an extension cord with the snake." Yes, it's okay to do. We've done it for years; I taped a piece of #14 SJO to the very first snake I owned (and I built it), extending past the stage box about 20', put Edison connectors on and never looked back. That was 35 years ago. These days we do the same thing except the wire is fatter, the snakes have more channels, and it's all 300' long instead of the 85' I started with last century.
Don't worry I'm not trying to do any of this myself, but I'd like to understand how it all works.
It works by taking all the outlets and putting them in one place that gets the electricity in a Big Gulp serving. This has several advantages, including creating a "star grounding system" where all ground paths originate from a single point and having known circuit loading (unlike plugging into a wall outlet - what else is on the same breaker, the frozen drink machine? Food warmers? Neon lights?).
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Here are a few examples
http://whirlwindusa.com/catalog/power-electrical-distribution/default/power-distro
For a simpler version, do an image search for "spider box." Ignore all the obvious home-brew units, especially the ones with two male pigtails.
A spider box is a distro that's marketed toward construction companies, not touring sound. They probably won't provide any voltage regulation, noise filtering, or metering.
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Ignore all the obvious home-brew units, especially the ones with two male pigtails.
Here (http://www.laserfx.com/Backstage.LaserFX.com/Systems/Support2.html) is a "power distro for dummies." There are several dangerous issues with this "how to" from both personnel safety and equipment protection perspectives. You'd have to be a dummy to use this distro.
There are some "double-pigtail" devices commercially available (example (http://www.hubbellcatalog.com/wiring/section-v-datasheet.asp?FAM=Marine&PN=YQ230)) to safely combine two 120V circuits to create a 240V (or 208V, depending on circumstances) circuit but they include safety features which overcome the dangers.
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I've heard that it's usually preferred if you have all the audio equipment on its own distro, including FOH. My question is how is that all wired together?
How do you get the FOH board wired into the same distro as the stuff on stage (or even back stage)? What if you wanted to put the entire system on a power sequencer?
That involves lots of copper! A "typical" large venue may have 2 or more tie in points. A 400A 5 wire with lugs or cams to go to the kind of distro you linked to for lights. Also a smaller 100 or 200A 5 wire for sound. Of course any given venue may have more or less than this. The tie points may be right off stage or several hundred feet away. Often times a 3rd tie in point may be provided for chain motor power.
A "typical" road show going into the above venue will travel with all there lights and sound equipment. That equipment will include a large trunk of feeder. Typically a hundred feet of heavy cam lock cables to go from the distro to the tie point, broken up into "tails" some short and some long cables. This trunk can be 600 to 1000LB on its own. Once the distro is tied in then a dimmer rack or another distro may take a feed from the threw on the first distro or a second tie point. All the rest of the equipment will be tied to these distros. The FOH "snake bundle" for audio may also include a very large cable just for power. Mine has a 10-3 Soow cable with Twist lock ends. The FOH lighting run for a festival my include an extra 100A run just for follow spots.
My point is that a large part of the weight shipped with each show is cable. I have done shows where it took a semi to haul just the cables! Even on VERY small shows, most of the weight of equipment was in cables.
Also keep in mind that a show may get inspected and the person doing the inspection typically can shut you down. You have to do every thing by the book (that book being the NEC listed above.) Even by the book your at the whim of the person inspecting and local codes. One place I use to work at needed a "spider box" The one we got cost 2x the money because we were in a "fire district" and it needed an extra listing that only 1 place could do. This is where experience and knowledge is invaluable.
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My knowledge of power doesn't go very far beyond standard 15 amp wall sockets and standard NEMA 5-15p connectors.
I know in more professional audio applications they use power distros. Where can I learn some of the basics of what makes up one and how they're hooked up?
Jason,
Lex Products and Motion Labs are just two of the companies that make portable power distribution. You can look to their products for reliable construction and code-compliance.
FOH Online had a Power Distro "Buyer's Guide" (http://www.fohonline.com/images/stories/11/05/29-31.200.1105.pdf) back in 2011...it may help shed light on what is considered "professional" versus "homebrew" or "consumer-grade".
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Understood, I'm not trying to do a DIY sub-panel or anything right now, I just want to know more about power distros in pro audio applications, what makes up one, how they're wired, etc.
Our equipment has always simply been plugged into the nearest wall outlet, so we've never used a dedicated distro for audio equipment.
Keep in mind that not many people here on the forum will give you distro advice. They're afraid of law suits if they give bad advice or something goes wrong and you blame them for it.
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Keep in mind that not many people here on the forum will give you distro advice. They're afraid of law suits if they give bad advice or something goes wrong and you blame them for it.
That is true, but the bigger issue is that people want a simplistic procedure, when what's actually required is understanding. In electrical power distribution, you can have a number of scenarios where things appear to work, but are very dangerous. The body of knowledge required to gain this understanding doesn't happen in a forum post or two.
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I just want to know what a power distro for a pro audio system looks like. What components are involved, and how it's all wired together.
pics of the distro de jure...
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I agree with Tom-building-really designing a distro is no different than designing power distribution in a building and before you are allowed to do that in most jurisdictions it takes a 4 year apprenticeship followed by 2 years as a journeyman plus enough understanding to pass a couple of tests-and that still doesn't guarantee that you are qualified. Not saying you have to be licensed-but it does take that experience and knowledge to do it right. And the price for a mistake on a distro can be far more permanent than getting the signal path wrong on an audio setup!