ProSoundWeb Community

Please login or register.

Login with username, password and session length
Advanced search  

Pages: [1] 2 3 ... 5   Go Down

Author Topic: Distro Questions, amp rack tie in  (Read 2351 times)

Jeremy Young

  • Jr. Member
  • **
  • Offline Offline
  • Posts: 85
  • Victoria, BC, Canada
Distro Questions, amp rack tie in
« on: March 07, 2017, 09:13:55 pm »

Hey folks,


This may or may not be the type of thing that I can really get advice on in a forum like this, but I thought I would give it a try.  I realize that ultimately, the authority having jurisdiction makes the judgment call, but I don't yet know the local electrical inspectors (and I suspect if I asked them this question with this terminology I'd be seeing more of them, lol).  I'm based in BC Canada for what it's worth. Here's my conundrum: 


My current distro came from an old install, it was built by an electrician (or so I'm told).  I have very little money invested into this thing, and I tried to pick up a Peavey rack mount distro before they were discontinued but.... three times being shipped the wrong product makes even the most patient online shopper give up.  I'm at the point where I need to either retire it, or customize it to fit my new strategy, but I'm hoping someone can weigh in on my strategy and tell me if I'm off the deep end.  I'll try to use accurate terminology the best I can, but feel free to correct me.


OK, so it's (my distro) simply a 4 x 15a load centre, bolted to a piece of wood (painted black of course) with a handle and some rubber feet. there's a short (3' maybe) nema14-50p pigtail to tie into a suitable receptacle, and this format does seem to be common in the venues I work so I'm happy with that connection type. 


Two of the 15a breakers are of the "common-trip" variety, for reasons I can't explain.  It uses bx cable (metal jacketed) to run the circuits to a pair of quad receptacles, one circuit per duplex.  I changed out one of the duplex receptacles for one that would accept a 20A plug (so I could plug in my Crest Pro-lite 7.5 power amp).  I realize this is probably a red flag already, since it's on a 15a breaker, but that's part of what I want to address.


The feeder cable is pretty worn, such that I can't make out much of the writing on the outside of the cable jacket anymore.  What I can read, says "30A", so I am not expecting a full 50A of capacity when plugged into a nema14-50R.  I don't think that's a wire size issue though, since the breakers would prevent the feeder from drawing any more than 30A. Correct me if I'm already mistaken please.


So, 30A 240v in, to 60A 120v out over four circuits.  so far so good (by my logic).  there was a brass screw inside, on one of the bus bars that was grounding neutral, which I removed after reading on this forum that neutral should not be bonded to ground anywhere but at the service entrance to the building.  Now my ego is flying, so feel free to deflate it.


I have acquired a 3RU rack panel with a 30A 125v locking inlet, and a couple quad boxes on the other side.  I installed this in my amp rack for a nice clean "single cable" hook-up to power all my amps.  For what it's worth, 30A @ 115v is plenty for my amp rack.  For those interested, it seems to be a Hubbell HBL2615 connector (nema L5-30R).


Of course, like anything free, it still requires money spent on it.  I have nothing that I can plug that in with, or into, so I thought I could come up with a strategy where I had two power cords built for this amp rack.  One would be a Hubbell HBL2613 at one end, and a Hubbell HBL2611 on the other (nema L5-30 R & P respectively), with some 8awg SOOW outdoor rated cable.  This would plug into a dedicated L5-30R that I would install on my distro (more on that later). 


The second cable would be the same L5-30R on one end, but just a nema5-15P (Edison as you Americans like to call it) on the other for times when I either don't have access to a nema14-50r, or I don't need the amplifier headroom (small venue).  seemed like a simple concept, taking advantage of the fact that the input on that rack panel is 115v so i can either give it plenty of juice when available, or a little juice (and get ready to run for those breakers after the kick drum hits!).  This way I can leave all of the amps plugged into the same rack panel, and just use the different cords for "small" or "medium" events.  less mucking about in the back of a rack on site in the dark, or at least that's the plan.


In order to get myself a 30A 115v receptacle, I thought perhaps I could use the two common-trip breakers, since they seem to be each from a different phase of the 230v power supply and two 15's makes a 30...right?  I'm sure there's something here I'm overlooking.  The thought was to use the knockout on the opposing end of the box from where the feeder enters, to install a short pigtail with that L5-30R connector on it, wired into those two 15a breakers.  then I'd just have each quad box on a dedicated circuit from the remaining two 15a breakers (one per pair of duplex receptacles) to power up backline/lights/fog/FOH/powered delay speakers/catering.... basically anything that's not in the amp rack.


I'm mostly just concerned about this whole common-trip 15a business, and whether that is a suitable replacement to a 30A breaker.  I'm going to end up spending a few hundred dollars on adapters and cable to make this work, which makes me think maybe there's a better way with the "right" stuff? Looking for some feedback, or suggestions on other methods to do what I want to do but perhaps better?  What have I missed? 


Thanks in advance!  Here are some pictures:

Logged

Rob Spence

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 2268
  • Boston Metro North/West
    • Lynx Audio Services
Re: Distro Questions, amp rack tie in
« Reply #1 on: March 07, 2017, 10:49:19 pm »

Purchase a proper distro.

The new 2017 NEC basically forbids home brew distros including ones built by electricians.

Your unit, in any case, is using lots of parts in unlisted uses by the NEC for many years.

Sent from my iPad using Tapatalk HD
Logged
rob at lynxaudioservices dot com

Dealer for: AKG, Allen & Heath, Ashley, Astatic, Audix, Blue Microphones, CAD, Chauvet, Community, Countryman, Crown, DBX, Electro-Voice, FBT, Furman, Heil, Horizon, Intellistage, JBL, Lab Gruppen, Mid Atlantic, On Stage Stands, Pelican, Peterson Tuners, Presonus, ProCo, QSC, Radial, RCF, Sennheiser, Shure, SKB, Soundcraft, TC Electronics, Telex, Whirlwind and others

Jeremy Young

  • Jr. Member
  • **
  • Offline Offline
  • Posts: 85
  • Victoria, BC, Canada
Re: Distro Questions, amp rack tie in
« Reply #2 on: March 07, 2017, 11:01:44 pm »

Thank you Rob!

That's exactly the kind of thing I needed to hear. And in a much less show-stopping way than it could have been.

Anyone have any recommendations for an off-the-shelf solution on a budget, now that the peavey is discontinued? Ampshop? Whirlwind?

Thanks!
Logged

Spenser Hamilton

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 557
Re: Distro Questions, amp rack tie in
« Reply #3 on: March 07, 2017, 11:17:51 pm »

Thank you Rob!

That's exactly the kind of thing I needed to hear. And in a much less show-stopping way than it could have been.

Anyone have any recommendations for an off-the-shelf solution on a budget, now that the peavey is discontinued? Ampshop? Whirlwind?

Thanks!

Theatrixx is a good option for those of us in Canada, little pricey, but top notch build quality.

http://www.theatrixx.com/en/products/distros/stage-box/

One of those would be a big improvement over what you have now.

Logged

Erik Jerde

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 307
Re: Distro Questions, amp rack tie in
« Reply #4 on: March 07, 2017, 11:19:10 pm »

Purchase a proper distro.

The new 2017 NEC basically forbids home brew distros including ones built by electricians.

Your unit, in any case, is using lots of parts in unlisted uses by the NEC for many years.

Sent from my iPad using Tapatalk HD

From a safety standpoint not bad advice.  However, since you're located in Canada the NEC doesn't apply as long as you stay north of the border.
Logged

Brian Adams

  • Full Member
  • ***
  • Offline Offline
  • Posts: 237
    • Adams Production Services
Re: Distro Questions, amp rack tie in
« Reply #5 on: March 07, 2017, 11:40:03 pm »

I think you're probably going to find that this distro is too small for you in the near future. Also, I'm not an electrician, so you should take anything I say with a grain of salt. That said, here's some advice:

First thing, no, you can't take 2 15A circuits and combine them into one 30A circuit. Well, you "could" if they were on the same phase, but it wouldn't be legal or safe. It's not possible at all if they're on separate phases, unless your goal is to have your distro weld itself together. The only safe solution to power your 30A receptacle is to install a single pole 30A breaker and replace the wiring on that circuit with a heavier gauge.

It's OK to have a your 20A receptacle on a 15A breaker, but you can't go the other way. For example, you couldn't put a 20A receptacle on a 30A breaker. You could put a 400A camlock on a 15A breaker if you wanted to though.

Having a two pole breaker on 2 separate circuits is technically OK, but not ideal. If one circuit trips for some reason, it will take down the other circuit as well.

That cable looks like it's probably 10ga, rated for 30A. The total capacity of your breakers is 30A per leg. Adding a 30A circuit will eat up half of your distro. If you're going to add a 30A circuit in addition to other circuits on the same leg, then you'll need a main breaker, since your distro can be fed from a 50A circuit.

I think you'd be better off with a 50A distro, which could have the 30A and a 20A circuit on the same leg. Honestly you'd probably be better off with a different panel in your amp rack too, maybe with a L14-20 or 14-30 rather than a L5-30, which could split your amp load between the 2 legs rather than having them all on a single leg. It would be more balanced, and the draw wouldn't be so heavy on just one leg. Would it be possible for you to rewire the amp rack panel to make it 2 circuits instead of 1?

No need to use 8ga cable for your amp rack when the cable that feeds the distro is only 10ga. 10ga is probably fine for your amp rack in any case. That's basically all I ever see on 30A circuits around here.

You're right, ground and neutral should not be bonded in a distro like this, they should be passed through individually. The bonding should only be done at the service entrance.

Your distro is small, and the mini breakers aren't as robust as full size breakers. There's also nowhere to add a 30A breaker without removing another circuit. If you're already planning on spending a few hundred bucks, you could probably rebuild (or replace) the whole thing for that amount.

Also, don't build a whole separate cable for your Edison to 30A cable, just build a short 12ga adapter from Edison to twist. And I'd rather see a panel mount receptacle in a box rather than a cable mounted connector, but that's up to you to decide.

Shop around. If you're patient, I bet you can find the parts you need for a lot less than you think. If you're going to buy something pre-built, Motion Labs is the industry standard, at least here in the US. You might be able to find a used Rac-Pac for a reasonable price. Whirlwind builds good stuff as well. Personally, I'd stay away from Ampshop and Dimmerrack products, since I've found them to be vastly inferior to Motion Labs. I'm sure they work OK for some people though.
Logged
Brian Adams
Adams Production Services
Vermillion, SD
adamsproductionservices.com

David Simpson

  • Full Member
  • ***
  • Offline Offline
  • Posts: 109
Re: Distro Questions, amp rack tie in
« Reply #6 on: March 08, 2017, 09:29:42 am »

Thank you Rob!

That's exactly the kind of thing I needed to hear. And in a much less show-stopping way than it could have been.

Anyone have any recommendations for an off-the-shelf solution on a budget, now that the peavey is discontinued? Ampshop? Whirlwind?

Thanks!

Amp shop makes some distros that would fit your needs: http://www.ampshop.com/distro.html

Whirlwind stuff is great, but can get a bit costly. I have a few distros from LEX Products that I love. http://www.lexproducts.com/products/entertainment/powerhouse-portable-distribution-boxes/50-60-amp-portable-distribution-boxes/50-amp-pagoda-jr.-to-gfci-duplex-receptacles

I second the comment of looking into a 50A Distro. Typically it is easier to find a 50A tie in compared to 30. It also gives you a decent amount of power for smaller to mid sized systems.

~Dave
Logged

TJ (Tom) Cornish

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 3617
  • St. Paul, MN
Re: Distro Questions, amp rack tie in
« Reply #7 on: March 08, 2017, 11:33:23 am »

Amp shop makes some distros that would fit your needs: http://www.ampshop.com/distro.html
NEC2017 520.53 "Construction. Portable stage switchboards shall be listed and shall comply with 520.53(A) through (E)..."

Ampshop/Dimmerrack and the like aren't listed, and therefore are even more marginally acceptable than they previously were.

It will be interesting to see if/when this starts being enforced.
Logged

Ray Aberle

  • Classic LAB
  • Hero Member
  • *
  • Offline Offline
  • Posts: 2765
  • Located in Vancouver, WA (and serves OR-WA-ID-BC)
    • Kelcema Audio
Re: Distro Questions, amp rack tie in
« Reply #8 on: March 08, 2017, 11:47:06 am »

NEC2017 520.53 "Construction. Portable stage switchboards shall be listed and shall comply with 520.53(A) through (E)..."

Ampshop/Dimmerrack and the like aren't listed, and therefore are even more marginally acceptable than they previously were.

It will be interesting to see if/when this starts being enforced.
That's a pretty good point. The other challenges with people like those is that if something fails (and I had that happen with a Dimmerrack unit, which is why I'll never shop there again), you're pretty much on the hook. Warranty coverage is probably non-existent, and if something happens where there's legal action, there's no defense on the part of the manufacturer like there would be if it's been inspected and listed/approved.

Quick and easy solution? Basic spider box. 50A I/O. 6-20A circuits. UL listed. Get a range to CS6365 adapter besides a standard CS6364-CS6365 cable, so you can work both with a range plug and a generator with 50A outputs. (Some people would also have a selection of 50A breakers, and a bare wire to CS6365 cable -- PLEASE make sure you absolutely know what you're doing if you attempt a tie in yourself, or have a licensed electrician do that for you, without fail, every time. And still meter that shit.)

-Ray
Logged
Kelcema Audio
Regional - Serving Pacific Northwest (OR, WA, ID, BC)

TJ (Tom) Cornish

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 3617
  • St. Paul, MN
Re: Distro Questions, amp rack tie in
« Reply #9 on: March 08, 2017, 12:08:06 pm »

PLEASE make sure you absolutely know what you're doing if you attempt a tie in yourself, or have a licensed electrician do that for you, without fail, every time. And still meter that shit
-Ray
Ray, The NEC uses words like "Qualified" and "Authorized" for anything that we would call a tie-in - requiring appropriate training/certification as well as official venue permission to modify their electrical system.  The basic rule of thumb is if it requires a tool, we can't do it.  The era of carrying around a bag full of breakers and doing a hot panel tie-in is over.

"Cord and plug devices" are the things end users can do - CS plugs, 14-50 plugs, etc.  Camloks are on the fence.

Particularly for lounge-level folks, you need to either have a licensed electrician permanently install appropriate receptacles in advance, or size the show to the existing power available.

To the OP - your distro is unsafe using #10 wire with a 50A plug, even if downstream breakers theoretically limit the current draw to 30A.  It's low-enough quality that I would abandon it and do as Ray said and get a construction-style listed spider box with an appropriate #4 feeder cord for the 50A load.

Logged
Pages: [1] 2 3 ... 5   Go Up
 

Page created in 0.11 seconds with 20 queries.