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Effects rack power conditioning/distribution

Discussion in 'Sound, Music, and Intercom' started by Anonymous067, Jun 27, 2009.

  1. Anonymous067

    Anonymous067 BANNED USER

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    As my personal IEM rack gets bigger (moving from 2 space which held EQ and IEM Trans) to a six space rack, I want to include a compressor/gate, EQ, transmitter, and have room for one other toy, as well as a power conditioner. I feel it would help because currently I have three/four cords to plug in from the back, and it would make things easier, and instead of a power strip, I may as well buy a decent power conditioner. Whats a good 15 amp version? I'm leaning towards Furmans stuff, but I don't like how their new lines look (appearance).
     
  2. Footer

    Footer Senior Team Senior Team Premium Member

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    Furman is the defacto standard. Sampson also makes a decent one. Rack Rider by furman is also good stuff.
     
  3. museav

    museav CBMod CB Mods Departed Member

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    Most of the 1RU rack mount boxes provide some filtering and over/under voltage shutdown but are not what I would consider a real power conditioner. However, in the 1RU surge suppression and 'power conditioner' genre there are many options. I am personally a fan of SurgeX, but along with Furman other options include Lowell, JuiceGoose, Middle Atlantic and Atlas Sound. In the MI/residential world there is also Samson, Alesis, MonsterCable, etc. I do like the series mode surge protection pioneered by SurgeX and now used in a slightly different form in some of the Furman products rather than the typical MOV based products that can 'sacrifice' part of their ability to provide protection each time they absorb a surge.
     
  4. TimmyP1955

    TimmyP1955 Active Member

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  5. epimetheus

    epimetheus Well-Known Member

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  6. museav

    museav CBMod CB Mods Departed Member

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    Sort of off topic but this subject reminds me of a related issue. NEC prohibits daisy-chaining temporary power distribution devices, basically prohibiting plugging one power strip into another. At least in my experience, devices like UPS units and rack mount power distribution seem to typically not be viewed as 'temporary' devices and I have never run into a problem with a rack mount power distribution device plugged into a plug strip or vice versa. However, I have been 'punched' on daisy-chained power strips. Just something to consider if you use a typical plug or power strip inside a rack or furniture.
     
  7. Anonymous067

    Anonymous067 BANNED USER

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    Can you daisy chain temporary power distribution devices for temporary gigs and such?

    Is there anything wrong with taking a rack mount sequencer, which only has two outlets per "phase" and plug a power strip into that one outlet, one and ONLY one power strip? IE, can you go, rackmount device>std. power strip, or must you only use rackmount devices (I assume NEC considers rackmount devices non-temporary?

    "punched"?? Explain?
     
  8. felixm

    felixm Member

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    I think what Museav is trying to say is you can't plug in one of the cheep 6 outlet power strips into another and into another and so on.

    It is not that you will over load the circuit but you could very well overload the last power strip that is plugged into the wall.

     
  9. museav

    museav CBMod CB Mods Departed Member

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    A search on "daisy chaining power strips" or anything like that will find plenty of discussions on the topic but the general concept is that due to increasing problems in offices, dorm rooms, etc., a few years ago the NEC and UL clarified some issues related to power strips or "relocatable power taps" and defined that these devices are intended to be used on a temporary (less than 90 day) basis, plugged directly into an outlet (not into an extension cord or another power strip) and not permanently mounted. Many of the same issues apply to extension cords, e.g. you should not daisy chain extension cords or use them for 'permanent' wiring. You also typically want to avoid placing multiple MOV based surge suppression devices in series.

    Devices that are hardwired rather than terminated with a plug and 'permanently' mounted inerently limit the load and are not relocatable and thus do not fall under the same categories. However, devices that are designed to be rack or furniture mounted but that connect to a receptacle via a plug do seem to potentially be considered the same, it is the plug that in effect makes the device relocatable and many of the same concerns still apply. For example, a sequencer may only have two outlets per 'step' but the ratings and potential load for the unit is dependent upon the potentially connected devices so it is the total number of receptacles on the device and the 'typical' load those represent that is the concern.

    Keep in mind that all of these issues relate to the potential conditions represented by the devices and not to the actual loads or conditions. It does not matter that you only have some minimal load currently plugged in to a power strip, it is the potential load represented should 'typical' devices be plugged in to all of the outlets on the device. Perhaps a simple way to look at it is that if you plug a 15A rated power strip into a 15A rated sequencer which is plugged into a 15A receptacle, based on 'typical' loads and the device ratings, you have connected a potential 30A load to a 15A device and that to a 15A receptacle. That you may have less than 15A of load currently on everything does not matter, the configuration based on the devices as rated represents a potential danger.

    I can say that when these changes occurred it significantly changed the way I design the power distribution within racks and systems. In some cases it simply means something as simple as having a duplex outlet to directly power two distribution devices rather than daisy chaining the two devices to a single receptacle. But in more complex systems it can mean a lot more thought and careful layout of how everything is powered.

    By "punched" I meant an inspection identifying it as an item to be addressed or a violation. It seems that these particular issues have become a focus for many Fire Marshals.
     
    Last edited: Jul 7, 2009
  10. TimmyP1955

    TimmyP1955 Active Member

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    That is correct. If you don't have something the quality of SurgeX, you are just as well off with nothing at all. Most anything else will have MOVs, which can cause various problems as they fail - and if you have spikes from which equipment needs protection, MOVs WILL fail.
     
  11. Chris15

    Chris15 CBMod CB Mods Premium Member

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    So not to get high and mighty, but Australia is reasonably well known for having some of the strictest safety standards in the world. So if someone could offer a comparison to US standards on this it would be appreciated.

    A powerboard is technically known as an Electrical Portable Outlet Device (EPOD). The relevant Australian / New Zealand Standard is AS/NZS 3105. The most relevant part of this to the current discussion is that where 3 or more 10A socket outlets, or a socket rated at more than 10A are provided, the device is required to have a circuit breaker per clause 4.5.3.

    In many of the standards relating to distribution there is an explicit ban on use of EPODs in series, but with breakers installed, there is no technical reason why they cannot be daisied as you can't overload the first inline without tripping a breaker.

    Does US code not require integral breakers?
     
  12. chadgreen

    chadgreen Member

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    Does this mean that if I have a Monster Power Conditioner that has a sequencer built into it that I can't add a generic power strip and zip tie it to the rack in case I run out of edisons I want to use in the power conditioner, technically?
     
  13. TimMiller

    TimMiller Well-Known Member

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    I hate cheap power strips they use thin strips of copper to carry the load from plug to plug. Well built rackmount units use 12awg wire connected from plug to plug. Also they use much higher quality circuit breakers. I have seen quite a few power strips melt tripping the main 20 breaker before tripping their little internal 15 amp breaker. Furman and every other power strip made uses MOV's for the primary surge protection. They are designed to sacrifice themselves, but with a little electrical knowlege, you can replace the MOV's for less than 5 bucks. After MOV's then you have your isolation transformer, which is the heart of a true conditioner. There may be relays and things in place for under and over voltage shutdown. Tripplite makes some very good stuff. Tripp-lite caters to the IT field. So they do make basic rackmount power strips because in major data centers, on top of your UPS system and Generator (generator feeds into ups in data centers). Its a major expense to have additional conditioners, so all you really need is a rackmount power strip. I have a few of those in my racks that are plugged into a furman or other power conditioner. I also have several tripp lite power conditioners and they work great. With furman you are paying a good percentage for the name. I once pulled apart a furman and a tripplite, and guess what, all the exact same components until it came to particulars such voltage metering, then they had their own little cusom boards, but they were about the same. But as far as filtering goes they are the same. You can take the same about of money and buy a furman PL-8 plus or you can buy a true big isolation transformer. There is a big difference between line filtering and isolation. Basically all single space units filter the power but dont truely isolate it.
     
  14. museav

    museav CBMod CB Mods Departed Member

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    Technically, that is correct. Chances are that your User Manual at least indirectly addresses this, likely discussing only connecting devices directly to the sequencer.

    Tim, few years ago Furman started using a "Series Multi-Stage Protection" approach in their 'pro' devices that is similar in concept to the SurgeX Series Mode Protection. Both Furman and SurgeX offer 'plug strip' type devices with some form of series mode protection rather than relying solely on MOVs, however these devices are larger and bulkier than your standard 'plug strip'.
     
  15. chadgreen

    chadgreen Member

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    So, how do they get away with it in I/T applications. I've seen a few networking nodes use a long power strip powering switches. Also, I thought that I saw at a television station a similar set up. Would this then fail an electrical inspection? Or, do you just have to calculate your power load accordingly and you will be fine? Thanks for the clarification.
     
  16. epimetheus

    epimetheus Well-Known Member

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    In IT applications, the long power strips you see in racks generally have their own circuits in a panel box somewhere.
     
  17. Chris15

    Chris15 CBMod CB Mods Premium Member

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    Most of those vertical rack mount power strips down here have a 15A plug and breaker which necessitates it's own circuit.

    Note also that given sufficient capacity, you can run breakers, RCDs, etc post UPS, which is applicable in data centres as well as things like OB trucks...
     
  18. museav

    museav CBMod CB Mods Departed Member

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    It is not really a matter of the load actually on such devices as by their nature that can change and thus it is a factor of the potential load. And you can use power strips, just not plugged into another power strip or similar device (and theoretically, not long term). For many of my systems I use products such as those offered by Middle Atlantic and Lowell that let you configure a power distribution strip in the rack(s) specifically to meet the requirements for each rack, but since those strips are hardwired to power and can be multi-circuit, you can have one or more power sequencers or plug strips off of them.

    The reality is that many people are not aware of or choose not to follow the requirement to not daisy-chain portable power distribution devices, however that does not make it an acceptable practice.
     

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