Three phase power and distribution


Have searched past threads and couldn't find the exact answer ... hopefully I can describe it here (even better if someone has the answer):-

Firstly, if I have a 3 phase outlet (lets say 32 amps), a 12 x 2.4 dimmer pack and a selection of 240V fixtures that run on single phase. Some of the fixtures I want to run off dimmer channels (e.g. PARs), some I don't (e.g. intels).

Is it possible/appropriate to split the feed from the 3 phase outlet so I end up with a 3 phase outlet to run the dimmers and have a few single phase GPOs to run the intels (so its all actually running off the same 32 amp supply). To clarify, I have seen the boxes of 3 x double GPOs (single phase) that you can plug directly into a 3 phase outlet, but I want a 3 phase outlet inbetween the two, to still be able to plug the dimmer in as well (and yes, total power for dimmer and intels combined would be less than 32 amps).

Secondly, a 3 phase 32amp supply means a maximum load of 32amps on the outlet e.g. 25 x PAR56 (240V) off one 32 amp outlet, its not 3 phases x 32amps allowing for 94 amps of loading, is this correct?? Does any of this logic change if/when i convert 32amps of 3 phase down to single phase?? Do I still only have 32 amps of power available when converted to single phase.

Sorry for the long-winded question, but wanted to give as much info upfront.
That's long?

While I don't major in Euro, I do wire for it frequently. Same as US, 32A per phase no matter the voltage into it. Not a total amperage on that plug for all phases but for each phase.

You will need something within your local code applicable to distribute the power to the various components / dimmer/non-dimmer outlet safely. That component to split apart the phases I don't know what is within your code to do specifically. Might try the Blue Room for the more localized how to or what and where you might rent if nobody else chimes in.

I take it for granted that your dimmer pack cannot or does not have enough slots avalable to have a few non-dimming modules replacing the dimming ones to do this given it has feeding it a:
Cee 5-pin Female Bal’s #3147 32A-9H 120/208&144/250v 32A (30A) Ceeform - blue 5-pin 3P+N+G Female “Kupplung”

Cee 5-Pin Female CeeForm #331509 32A-9H 120/208&144/250v 32A (30A) Ceeform - blue 5-pin 3P+N+G Female

(Leviton now also makes these plugs now.)

Given your dimmer does not have enough available slots to loose some dimmers in exchange for non-dim ones, or the modules are not feasible to rent or buy, in the US, I would do some form of portable power supply that complies with our codes to feed both such as in this case say a three phase switch panel or circuit breaker sub-panel dependant upon the amount of outlets it needs to provide for. This panel mounted to plywood that feeds the various outlets, or even a rack mount version where needed. Various definate rules about doing such things and even as under current modification by the proposed ESTA single conductor feeder requirements, how it's done is changing in as yet un-known ways. How I do stuff these days might be changing at some point.
What are your conncetions comeing out of your three phase disconnect.

If its CamLok You can get a Distro and use the passthrough to power your dimers.

If its not Camlok you can buy a distro that is made for what ever type of connector you have.

Unfortuneatly when dealing with power home made is not always the best choice.

If you were in the states or even London i would sugest you call TMB they are leading experts in DIstros and such. Give there london office a call they will atlest beable to advise you on steps to take.

Ship - thanks for responding ... not sure where the UK thinking is (I'm in Sydney Aust), perhaps its the way I reference the power??? The issue is more that the work I do, the venue usually has its own dimmer pack, but not always enough single phase power to run the intels, so was hoping to put something between the house dimmer pack ad the outlet that would facilitate this. I'm trying to dig up manuals on the relevant dimmer packs that might tell me if its possible to run individual dimmer channels in a stand alone mode so that they act like a standard single phase outlet (the equivalent of turning the pre-heat up to 100% I guess). Is this likely???

Jon - yep, all good info there, and no plans to knock up something homemade, will leave the hardware and wiring up to the licensed professionals (which I am not). Excuse my lack of knowledge, but i don't think they are "camlok" connectors. I think they are "twistlock" connectors (the connectors that you plug into the outlet and then screw the orange ring on the plug onto the male thread on the outlet (is this correct??).
Beam I would talk to your local electrician as he will know the proper regulations for distribution. I know an electrician here built a portable distribution board for this sort of thing.

It was built in a plastic distribution box of the type that is completely enclosed. It had a couple of metres of three phase cable with appropriate 3 phase plug. On the ditribution side there were two 3 phase outlets. Also there were three double socket outlets, wired one to a phase. There was also all the appropriate circuit breakers included.

It would probably cost $400 - $500 to have made as the three phase plugs, sockets are probably a $100+ each.

There are also pre-made ditribution boxes to do this. I can't think of the brand but if you go to your local electrical supply company they should put you on to them. I first saw them in the army but have seen them in civy street they are pretty generic.

You probably would be better to spread your intelligent lights supply across all phases to make it easier to balance the load on the dimmers, to avoid tripping the breakers.

Just to give some idea of the sort of 3 phase plugs Beam is likely to be talking about I have included a couple of links.

The links below are New Zealand standard for three phase power used in lighting distribution. As New Zealand and Australia share the same standards these are probably similar to the ones Beam_1973 is talking about. If I am wrong my ANZAC buddies will be along to correct me.

As you can see these plugs push in, then the outer ring is screwed onto the socket thread. So I am not sure how much they differ from what the US call twistlocks.
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Cutlunch - re your links to the pics, yep they are EXACTLY the ones I am talking about. And thanks heaps for your advice on costs etc. And you got ahead of my next question regarding splitting intel loads across the 3 phases, I thought that would be the case, but thanks for confirming it.

I can finally sleep easy on this issue.

Switching dimmers to non-dim probably or at least normally would not do it properly - though it might and or at times with some gear is done. Instead a relay module that completely replaces the dimmer and is like a DMX controlled on/off switch would be preferred. That said the manual might say it's possible but you will probably have to drop a line to the manufacturer on that question given it's a ballast based fixture. If incandescent, shouldn't be a problem.

Sorry about the British thing, forget there is more than us/them (Europe) or you guys down under.

Feed thru power tapping distro would be probably the best solution. Good point about distributing and balancing the load Cutlunch.
I've seen exactly what you are after. It wasn't branded, but it goes along these lines: Clipsal 32 amp 3 phase plug on ~2 metres of 3 phase cable --> 3U Rack Case -->
32 amp 3 way breaker --> 32 amp socket on rear panel &
3x 20 amp single phase breakers --> 1 double GPO front & rear per phase

With neons above each breaker to show they are on. If I were building one or getting it built, I'd be inclined to put in an RCD as well. As I understand it, since it has a flexible lead & a plug, you do not need to be a licenced electrician to build such a distro (in NSW at least... I THINK), check with a sparky.

As far as replacement with non-dims modules goes, I assume Beam is talking about the typical dimmers we have here, like these, so there are not individual modules per say, it's all together.
Chris - yeah, the spec you talk about sounds exactly like what I would need, but will probably get a sparky to build it anyway, thanks for that.

Right with the suggested dimmers too (although, more often using the HP series rather than the FP series).
No Worries. Nice to see another Sydneyite. If you are after more information, just ask.

HP or FP (or GP for that matter) is simply a question of cost and need for more advanced features. The more important bit is that they aren't like the racks that seem to be the norm in North America.
I'm new here, and not directly familiar with 3 phase in AU. But here is my .02.

What is your dimmer power requirements? If it is 32 amps 3 phase, then it may not be practical or usefull to keep the 32 amp connection the service disconnect. You might need to get a box made up with say 60 amps (here in the states 3 phase boxes are usually 30 60 100) that then has a three pole 32 amp breaker with feeds the same connector people are using on the dimmer today, and then has 3 20 amp breakers that feed a set of dual outlets. Here in the US depending on budget I probably would also look at going to 100 amps, adding 6 20 amp breakers two per phase, and then wiring in a socapex connector so that it would be easy to run 6 lines for your intels, but that would be more expensive.

Just a thought

OK. I think I need to clarify a couple of things.

Firstly, remember that we in essence use only half the amps as North America because of the 240 / 120 volt difference.

Secondly, camlok / powerlok I do believe are used down here, I've never seen them though, but they are only used on high current feeds. The 32amp 3 phase connector like this is the standard means of connecting 3 phase down here. In many cases, they are littered through venues. They are also what is fitted as a standard plug on most dimmer packs.

There are limited numbers of 40 and 50 amp 3 phase connectors of the same style in use, but they are certainly in the minority, though the 40 amp variant is gaining momentum so that the dimmer can be fully loaded without overdrawing the connector.

For that reason, going to anything of higher amperage is in fact counterproductive, as in many cases, you would not be able to plug it in. In an ideal situation, yes, but since that is not what is installed in the very great majority of cases it is predominantly useless.

As for service disconnects, I don't know anything by that name, but if it in reference to a point where 3 phase is hard wired in, then as far as I know, they are only used in HIGH current connections. Certainly the most common thing is for multiple 32 amp runs before bumping up to camloks / powerloks / hard wired runs. Though this is based on my somewhat limited experience, so the really big show might be doing something entirely different.

I interpret it as beam working mostly in clubs etc. (I could be wrong though). I could almost guarantee that they will have 32 amp sockets and nothing else.

This is rapidly turning into one of those things which completely confuses people from other countries, simply because you haven't seen our venues or used our power connectors. I find the same in reverse.
I understand standards and practices are different around the world ;-)

Back to what I THOUGHT was your original question.

How much does your dimmer draw in amperage? Typically when the connect a three phase dimmer to a three phase service, they will split the dimming modules evenly across the three phases. SO for instance if you have a each dimmer rated for 2400 watts, then you are using 10 amps for each dimmer, and so your power connection would support 9 channels of dimming. IF this was the case then you could not put any other connection on that 32 amp service.

So if the dimmer you mentioned originally is actually a 12 by 2.4 it should not be able to run on the 32 amp service since it would need 40 amps per three phase leg, and at the very least you would not have any additional amperage left over to support your outlets.

If on the other hand your dimmer was 1200 per channel, and you had a 12 channel dimmer, you would only be using 20 amps per leg (4x5) and then you could have build a box that plugged into the 32 amp three phase, and and a connector out for 32 amps for the dimmer (typically with a 20 amp breaker per leg) and an additional 10 amp breaker per leg connected to an outlet that you could use for your intels.

I am guessing that you also could probably get or have made a box that has a 32 amp connection to the outlet you mention, and then it has a series of breakers and then outlets on it.

In the states the typical way it is done is to just have a high amperage service disconnect that you wire in your own distro to, usually in the larger venues these are 400 amps.

Anyway hope it helps

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Sorry, it seems I was a little rude in my last post.

To answer the question, dimmer packs are 12x 10 amp. I am aware that the maths does not work out for a 32amp outlet. The trick is to not fully load each channel of the pack and/or not have them all at 100% at the same time.

Because there is rarely a full load on the dimmer pack and circuit breakers naturally tolerate some overload before tripping, in most cases, you can get away with drawing additional power without problems. In many cases, lights and audio are run off the same 3 phase outlet, especially when it is from a generator.

l guess the bottom line is that what Beam wants can and is done, but when doing so, you need to be particularly careful not to overload your supply.
hey no problem

You just have to be more careful with three phase, since as the legs get out of balance the neutral leg starts to carry more current. and of course if you trip the breaker you will loose everything. It certainly would not be difficult to make up a simple thru box with a outlet box for each phase, and have a male on one end and female connector on the other and I guess if you trip the breaker you trip the breaker.

I'm downunder and we have the same system as Aussie. We don't have that much of a problem with the breakers tripping if the three phase is out of balance.

A amatuer theatre I work at has both GFCI and circuit breakers through the distribution. Even if the balance on the load is 15amps different it won't trip the GFCI. And yes the GFCI's work. We had a faulty cable to a light bar the cable ended in a 3 pin plug at the patch bay, plug this cable into a pack and instantly the GFCI tripped. But I try to even the load where I can just to help minimise wear and tear on the dimmers.

In our venues the three phase usually terminates in 32A sockets we have as standard on our dimmer packs. The next level circuits (not outlets) up would be 60A per phase and so on until you reach the maximum you need and the building wiring is designed for. There are fuses or circuit breakers rated for each level.

If you need more power (provided the bulding can supply it ) or outlets then are hard wired in, you need to get what we call a Registered Electrician ( electrical contractor) to do the work or it is illegeal. We can only plug into approved power outlets

As Chris has said we don't run every channel on the dimmers on full load so when they design the power supply for theatres they take this into account, it's called derating. Hence the 32A instead of the 40A someone suggested.

This post and others have made me wonder about the US electrical system. Could someone please post links to good websites on the topic.
To clarify ... yes most of my work is in pubs/clubs that run 3 phase 32 amp outlets, or on some ocassions only 3 phase 20 amp outlet :( which is very limiting. Most of the time, we are lucky enough to be able to run lighting off a different circuit to the PA which obviously increases lighting capacity as well as minimises potential for battles with the sound engineer about hums in their PA allegedly caused by lighting ;)

As was mentioned in my initial email, it was always my intention to NOT run more than a 32 amp load when dimmers and intel's were combined with a thru-box or the like. Again it comes down to just being smart with programming and setting scenes that don't call on all fixtures at once to avoid the trip.

Unfortunately, when the power is already established in the venue, its not so easy to ask them to just run another 32 amp circuit etc etc.

All very valuable discussion.

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