Design Stage Power Distribution - Australia

[TassieBogan]

I'm looking to hopefully design a stage power distribution system to use primarily with rock 'n roll gigs, to power guitar amps, pedal boards, keyboards whatever these modern bands use these days.

The main reason behind this is that whenever something fails on a show, 9 times out of ten it's the cheap and nasty plugboards, and those dicky little *surge protectors* that are built into them. So the decision has been made, after several showstopping incidents, to throw out our stock of them. It's left us with something of a problem though, and using endless chains of piggyback plugs is hardly a long term solution.

I'm thinking something along the lines of a box, like you would see on a multicore, with a 30A C-Form inlet (edit- SINGLE phase), 4-6 10A outlets, and a 30A C-Form outlet, so as to daisy several boxes together across the stage.

BTW i'm in aus, so any C-Form gear wouldn't be interchangable with anything else, and the standard 3-phase plugs here are hugely overpriced.

any thoughts? anyone have a system that works well for them?

 

[derekleffew]

Sounds like you want to build a band stringer.

I don't know anything about AUS, but in the US, I'd suggest either Motion Labs or NuTech Doghouse. I'd also caution against building something yourself, unless it met the standards of UL 1640.

Perhaps Chris15 and others could tell us what's common down there.

 

[Chris15]

It's not surge protectors, it's the 3 cents 10 amp circuit breakers that are required to be installed in any EPOD having 3 or more outlets by the Australian Standards. Unless you meet the standards, you can't market it, it's that simple.

Now to resolve your issue at hand...
UL means diddly squat down here.
Bosbox out of Adelaide make some reasonable distribution stuff.

BUT, there is a system that wipes the floor with anything else I have ever seen. Trouble is it's not commercially available.
It's the system Norwest use and it was designed in house.
Basically you have a stage box with a 16A inlet, a 16A outlet (both on blue 60309) and then 8 GPOs on top. The box has been designed so that the steelwork protects the inlet and outlet connectors pretty well and there's a handle in there for easy of use (and something to cable tie it in place - stories from the trenches possibly best not told here...)

There was an ongoing debate as to whether the box should be equipped with a circuit breaker or not.

I shalln't bore you with my rants about the 56 series plug, it's price is the least of my gripes.

I guess fundamentally you need to take a step back and look at the bigger picture of the whole distribution system. Can you tell me what that looks like or is envisaged to look like?
What would be the normal rating of your incoming feed? Do you run on one or more 32As? 63 on some form of connector? Powerlock? Tails?

 

[bishopthomas]

I also am not familiar with Australian connectors/codes but what is common here is just a length of SO cable with quad boxes attached every few feet. Some people get fancier and/or buy a premade system such as what Derrek linked to. At some point I plan on making quads with Powercon connectors. There would be an inlet and a through on each quad, then just make up a mess of cables with Powercons. You place the boxes where you need them on stage then connect the dots.

I don't know about "C-Form" but since you also mentioned "single phase" I will assume that you're thinking about putting an entire distro on stage for band power. I wouldn't worry too much about multiple circuits unless you're doing really large bands or trying to backline (and power) multiple bands at once. For basic setups a single 20A circuit works just fine for us. Sometimes we'll run another stringer if we need it, but that only happens maybe 10% of the time.

 

[TassieBogan]

Chris, It was intended to look very much like the "stringers" on the motionlabs link in derekeffew's reply. (i'd copy the link, but not very forum-literate)

As for out distro system as a whole, we have a number of 30A single phase c-form outlets off our 100a powerlock dizzy (as well as all the usual connectors), and also on several 32a dizzys, that are usually used to drive individual amp racks, so more than one stage power feed could be run if needs be.

It's possible i got the idea of a norwest box, but i don't recall ever having worked with them

 

[Chris15]

There's no reason you could not build it in an inline sort of form factor.

I would not be keen to do it with a 32amp mains for 2 reasons;
The first is that 16a cable is much lighter to coil at the end of the gig and much more flexible if you are doing a rolling cart or the like and rolling the cable as the cart moves.
The second has to do with The Rules.

20A is the magic number for RCDs in AS3000. Any final subcircuit less than 20A and feeding socket outlets needs to be RCD protected. The way I interpret the clause in AS3K in the context of entertainment power distribution is that the RCD should be placed when the circuit size becomes less than 20A. So if you feed 32A into an amp rack, the amp rack distro should have RCDs. If we follow that through and you fed your stringers with 32A, you'd put the RCD in the stringer box. That's great right up until some guitarist plugs a dodgy amp in and trips the RCD mid show. If the RCD is at the distro off stage you can gracefullly reset it (there is wisdom in home running different parts of the stage to the dizzy). If that RCD is on stage (bearing in mind you won't know which one has gone if you have a chain - there are other issues there with protective device grading or more accurately the lack thereof. Effectively you can be very quickly left up brown creek without a propulsion device.

 

[TassieBogan]

Thanks for clearing that up

Yes our racks have RCD's but i wasn't aware of it's being a requirement.

Back to the drawing board. It simply would've been nice to integrate it into the existing system. 32 amps was being rather generous for stage power anyway, so a 16A system would be a go-er yes?

 

[Chris15]

Drawing board perhaps not.
All you'd need to do to fuse the 2 ideas is add an extra box to the system.
1 32A in, 2 16A outs with MCB/RCDs.

There are no specific rules for temporary electrical installations such as those for entertainment in this country. For "Shows and Carnivals", yes, but from memory they specifically exclude stages. In NSW we are starting a process that will see retrofitting RCDs into workplaces mandatory within the next 12 months on high risk devices and 4 years for total coverage, but there are a very small number of people you actually understand the rules as they related to what are effectively cascadable reticulation units in the context of AS3002 which form the backbone of entertainment power distribution in this country.

There is NO standardisation amongst the big boys, cross connecting between say JPS and NWP is a nightmare to say the least, and let's not try and make it play ball with CTS or Bytecraft or any other lighting company either.
I will note Masstechnik are using 16A cee on their superscreens.


The other trick with a 16A based system is that THEORETICALLY you could create a cable with a 16A female and a 10A male, you'll work out why that would be useful...
There is no diminishing of current carrying capacity, so in theory you would be kosher. An over zealous inspector (not that I have met an inspector) might not necessarily agree. Ultimately it would be Workcover Tas and your insurers who would have the final say.

 

[TassieBogan]

There is NO standardisation amongst the big boys, cross connecting between say JPS and NWP is a nightmare to say the least, and let's not try and make it play ball with CTS or Bytecraft or any other lighting company either.

And then you get all that weirdo international stuff... I remember one of Nick Cave's guys coming up to me... " Where can i plug this in?" " Ummm WHAT IS that?" lol

Anyhow, will run it by the sparky at work, I might chuck some pics up when this gets underway. Cheers for the assistance

 

[gcpsoundlight]

The other trick with a 16A based system is that THEORETICALLY you could create a cable with a 16A female and a 10A male, you'll work out why that would be useful...

Aaah, problem. If I recall from my recent testing & tagging certification, you can make that, but it cannot be tagged, as it is a "non standard cordset". Which then leaves you up S*** creek, as you can then not take it into the venue etc....

I absolutely agree about the JPS/NWP/Bytecraft (who arn't even bytecraft anymore) debarcle!

 

[Chris15]

Aaah, problem. If I recall from my recent testing & tagging certification, you can make that, but it cannot be tagged, as it is a "non standard cordset". Which then leaves you up S*** creek, as you can then not take it into the venue etc....

Last I checked, which admittedly was a little while back, AS3760 did not say anything about non standard cordsets not being able to be inspected and tested...
Your certification, with all due respect, is not worth the paper it's printed on, none of them are...

 

[gcpsoundlight]

Last I checked, which admittedly was a little while back, AS3760 did not say anything about non standard cordsets not being able to be inspected and tested...

I understand that, but all the same, I'm not going to test something like that when our instructor cited that sort of thing as an example of something that should not be used, as in this day of litigation, if something were to happen, then there is the possibility of it coming back to me if my name is on it. as it is, if something has a 16A socket on it, logic says that it should be able to supply 16A. if it is only being fed by 10A, and someone dumps a load of higher than that on there, all that is going to happen is it will trip the breaker, and you are back to the same problem.

Your certification, with all due respect, is not worth the paper it's printed on, none of them are...

.... Really. So why do they exist then? I understand that T&T does not delve much into electrical theory, but I understand enough to know what is safe and what is not. Now, NSW is probably a little bit different to victoria, but as far as I am aware, I have done the training, therefore I understand the topic, And have been deemed competent. It is like driving. Would you say that a drivers licence is not worth the paper? in which case, why not let everyone drive at whatever speed they like?
You get my point. With all due respect, I can see that you have been working in the industry, and understand a lot of these things, but F***ing around with electricity is not one I reccomend.

**end rant**
(The section on load feedings came from my grandfather, who is an A grade sparky)

 

[Chris15]

My feeling is that strictly speaking you should have a 10A breaker inline.

BUT, remember that circuit protection is fundamentally there to stop the installed building wiring igniting, nothing else. There IS no rule preventing you from running a 32A circuit to feed the GPOs in your lounge room. You have to use I'm guessing 4 or 6mm depending on the installations, but that's a guess, I don't have my copy of AS3008 here with me. You *will* run into problems getting that much copper into the terminals. BUT, it's legal.

I'd ask you to consider that we have no problems at all with putting a 10A outlet on a 150w inverter and we all know that has absolutely no chance of supplying 10A without igniting or some other badness. So why then if the limiting current carrying element is the inlet plug, should we be concerned?
I *can* pull 40A a phase through a Jands PDS12. Or I could put a mobile phone charger on each outlet and be drawing under an amp in total. Are you saying I still need to have every element rated for that 40A? Why could I not adapt that to fit into say a 10A 3 ph socket?

I can legally put a 50A outlet in and breaker it at 10A. Likewise I can put a 10A outlet in and feed it on a 50A circuit. Is either of those wise? Likely not.

Oh and btw, if we are going to use your theory, you will never be able to tag a Powercon. The Powercon is rated at 20A and the plug on the other end is probably a 10A connector...

 

[DuckJordan]

I understand that, but all the same, I'm not going to test something like that when our instructor cited that sort of thing as an example of something that should not be used, as in this day of litigation, if something were to happen, then there is the possibility of it coming back to me if my name is on it. as it is, if something has a 16A socket on it, logic says that it should be able to supply 16A. if it is only being fed by 10A, and someone dumps a load of higher than that on there, all that is going to happen is it will trip the breaker, and you are back to the same problem.


.... Really. So why do they exist then? I understand that T&T does not delve much into electrical theory, but I understand enough to know what is safe and what is not. Now, NSW is probably a little bit different to victoria, but as far as I am aware, I have done the training, therefore I understand the topic, And have been deemed competent. It is like driving. Would you say that a drivers licence is not worth the paper? in which case, why not let everyone drive at whatever speed they like?
You get my point. With all due respect, I can see that you have been working in the industry, and understand a lot of these things, but F***ing around with electricity is not one I reccomend.

**end rant**
(The section on load feedings came from my grandfather, who is an A grade sparky)

Not to delve this further off topic, But just because you can take a test and have done "training" doesn't mean you actually know what you're doing. I see it as what here in the states we would call being a "certified electrician". Supposedly you know what you are doing but you legally can't install any kind of electrical work. I can get tons of certifications for everything under the sun including how to use pyro. Does it mean I know what the intracacies involved with keeping people safe... Maybe, maybe not.

I'm not sure what the codes are like in Aus but here in the US having multiple boxes on a single line is okay up to a certain point. As long as its a temp install. In the place I used to work at we had something similar for our Pit band lights. It was just a long string of SO cable with 4 outlet boxes every 5 foot or so. I think there was a total of 6 boxes per run. This was a public High school and was bought by the school district for the space. It wasn't UL listed but they still bought and used it.

But I second the question of really how much power are you going to need to draw on a single line because 30 amps seems to be quite a bit of power.

 

[Chris15]

Alright now, you opened Pandora's box, ie. me on Test and Tag.

AS3760 is the standard. How many of the companies that go around and do all your schools and what not actually own or heck have even read a copy of the standard?

I am happy to be told I'm wrong, but it was that the unit / certificate everyone teaches was only accredited in Queensland. But many many many RTOs will tell you it's nationally recognised. Anything that is not traceable to the AQF I don't even want to know about.

A competent person in the eyes of legislation is one who through some combination of experience, training or qualification. I personally have the knowledge to do a T&T with other than a PAT. Do I have a piece of paper to prove I am "competent"? No. Would I be able to tell a judge I knew what I was doing? Yes.

98% of items that fail should have never made it to the PAT. The visual is FAR more useful at detecting problems. A PAT will pass a cable with a large gash and exposed copper that immediately fails a PROPER visual.

And mate, I have made electrical adapters that in their usage were perfectly safe. Use them for anything else and bad things happen. I agree completely not to screw around with power, but to try and claim that adapting to a 10A plug is the end of the world is wrong. Most stage stringers would not even be drawing 10A anyway. I am also more than confident that a 10A plug of any name brand will sustain at least 16A indefinitely. I say that because the current carrying pins are EXACTLY the same dimensions as the 15A 3 pin plug. Therefore they must be rated to 15A and so long as the whole assembly is not in a poor state of repair and thus not mately cleanly, they will be just fine with a 15A load.

Also, let's be realistic about this anyway. How often will you actually draw even 10A down a typical stage power drop?
You want to send multiple drops onto stage independently to minimise the collateral damage if something trips or gets yanked, and if you have a setup small enough to run it all off the one run then you probably don't have a huge current draw anyway.
Note here that this is purely audio, if you want to add lighting to it, all this theory need be throw out the window, you are not talking about small, diverse loads at that stage.

Fundamentally, the heart of the issue is that there is no applicable AS, so we end up falling under bits of 3002, bits of 3012, parts of 3199 (?) are applicable and all of that comes under the umbrella of AS/NZS 3000:2007 (as amended). Get everyone follwoing the same standard and the industry might have somewhere to start to move forward and away from dangerous and unwise practices...

 

[gcpsoundlight]

... aah, yes, standards. the great thing about them being that there are so many to choose from!

I agree that, in many situations, it works fine. My thoughts were that, having worked with lots of young (ie: under 16) people setting up stuff, they assume so many things, and often manage to do things I would have a hard time doing if I wanted to.

I absolutely agree about pin size, my only thought was on a stage, say some set needed fixing, and the welder see's a 16A plug sitting there and uses it. Unlikely, yes, but possible.

And T&T law is just designed to confuse people.... sorta! don't know about up there, but down here the piece of paper is not hard to get. and yes, a visual inspection can do wonders. Some people I know need to actually look at stuff, one guy missed a 1cm gash in a power lead, which lead to me nearly being electrocuted when I then used said equipment.

I have no problem with adaptors either, I just like things to pick a rating and stay at it until necesary.

 

[Chris15]

I think it's really really important to draw a line between what's appropriate for use only by competent professionals and what Joe public is going to struggle to cause significant damage with.

In the latter case, you work with 10A plugs and sockets because that is what people know.
When dealing with professional use equipment, you can take a little more latitude in your design decisions, but ultimately it needs to be loader proof...

btw, it's the fact that the piece of paper is so easy to get that makes it of such little value
All T&T can ever do is say that at the instant in time it was tested it was "safe". Never mind you could have I dunno, run a forklift over the cable since or even, for the ultimate irony, nicked the cable when removing the old tag to put the new one on.

 

[gcpsoundlight]

...for the ultimate irony, nicked the cable when removing the old tag to put the new one on.

Funnly enough, that is how I almost got zapped the other day!