| Mark25 |
All,
What are the safety rules about suppling defferent pieces of 220v single phase equipment (coupled together as one system) from different phases, to spread the load?
i.e. when using active powered speakers, supplied from other phases to the pre amp.
TIA
Mark |
|
|
| pinkmouse |
GLC licensing rules used to state that equipment powered by different phases had to be at least 3m apart, so it was impossible to touch both bits of kit at the same time. However, I won't go into the twisted logic behind that... :)
The guidelines we used to work to though was that if the kit was racked up properly, (like a real amp or dimmer rack), then it was okay to power from 3Ph, but if not, it had to be spaced apart. I also used to patch my dimmer racks across phases so that all of, say, one six lamp bar was on the same phase, and preferably each truss had it's own phase.
As regards noise, one phase for PA right, one for left, and one for FOH/ Monitors/ delays etc. |
|
|
| imix500 |
| This is done every day in large systems. Honestly, in audio you just need to watch for gross unbalanced loads between phases. So, if you're running a dozen amp racks it is something to look at and is pretty easily done. Just watch the load on the neutral, that will tell you how bad the unbalance is. Proper ac grounding is more important with three phase "Y". |
|
|
| imix500 |
| We posted at the same time. I agree with pinkmouse. |
|
|
| Mark25 |
| quote: | Originally posted by pinkmouse
GLC licensing rules used to state that equipment powered by different phases had to be at least 3m apart, so it was impossible to touch both bits of kit at the same time.... |
But surely that solution would be negated by the fact that the active powered speakers, (im my example) have a metal XLR connector, which you may choose (i wouldn't) to plug in while the system is powered? |
|
|
| pinkmouse |
I told you the logic was twisted!
I think the idea behind it was so that someone couldn't stick their hand in one bit of kit, and another in a second bit of kit on a different phase and get a 450V shock. With suitable racked up kit properly enclosed that isn't a problem.
What exactly is your situation, I might be able to give you more specific advice? |
|
|
| pinkmouse |
| quote: | Originally posted by imix500
Just watch the load on the neutral... |
Sage advice. Get a clamp meter. ;) |
|
|
| AndrewT |
Hi,
following on from Pink's 3m comment.
I think (not sure) that sockets on different phases must be more than 3m apart.
that it is preferable to not have mixed phases on sockets in a room.
that the distribution board be clearly marked 400V to alert the electrician that your home is DIFFERENT!!!
I have the garage and some of the house on blue, most of the house including kitchen & appliances on yellow, lighting and the listening room sockets on red. |
|
|
| Mark25 |
| quote: | Originally posted by pinkmouse
...What exactly is your situation, I might be able to give you more specific advice? |
Ok Al, sorry for the delay in reply! The system is as follows: 2 x Mackie 240v active speakers (one is a SA1232 model) connected with XLR's to a 240v mixer desk. The three items and one subwoofer are supplied from a 3 phase supply box, with one common earth. The 240v kit is spread across the phases to balance the load. The system is used in restuarants, halls and tents.
I wouls suggest that in this sort of situation, it is well possible that one speaker could easily get plugged into a local socket, rather than always being cabled back to the supply box, for whatever reason.... |
|
|
| pinkmouse |
Looking at the spec sheet, I see they pull 16A each. The first thing I would do, (to stop them being plugged into any old wall outlet), is convert all the connectors into Ceeforms. Then you have two options, get a 16A 3Ph distro made up and run one phase to each speaker and one to FOH, or go single phase.
This may seem as if I'm not answering your question, but sticking with single phase has many advantages. For a start, most medium sized power in European venues is single phase. Three phase usually starts at around 63A, overkill for you, and employs expensive connectors and cabling. If running off a gennie, it's also much easier to get a phase that's free of lights and catering, both of which can cause problems, and unless you're dealing with pro Rock and Roll gennie companies, all their distro will likely be geared around single phase distribution as well.
Does that make sense? |
|
|
| thevoice |
I'll agree with pretty much all of the above. I'll just add that a lot of audio guys I've worked with are moderately keen to use just one phase for audio, when possible, and even more keen to use a single supply point. The last point point helps with avoiding earth loops in venues that are old and wired a little strangely (or new venues that are still wired strangely, for that matter).
If you can avoid getting a split off the lighting supply, that is even better for all concerned and stops us lighting guys getting dirty looks when we fade out a stage full of par 64's in a quiet bit.
edit: I've just re-read your post above, with the kind of load you are talking about, load balancing is not much of an issue. You might be perfectly balanced but if the kitchen turns on a chip fryer or the lighting tech fades out what happens to be one phase of lighting it all goes out the window in any case. The PA is usually a fairly insignificant load compared to things like that. |
|
|
| pinkmouse |
| quote: | Originally posted by thevoice
...a stage full of par 64's in a quiet bit... |
Par cans? Par Cans! If you haven't got nodding buckets on the rig, at least you could get Source4 pars! That's just soooo 80's :D
al/ AKA ACL-lover |
|
|
| imix500 |
| Yes, but the roar of wiggle light/scroller fans is just as bad. Then just wait till they all move! |
|
|
| thevoice |
meh, I'm old school ;)
I know of venues around Melbourne that are still using Strand Pattern 23's. I know of one using Pattern 45's, from over 50 years ago, complete with asbestos leads. (I left there as quick as I could.)
I've used (and serviced, unfortunately) nodding buckets as much as anyone, but I still love a PAR and they're still used pretty widely too, once you get out of the top end. Pro theatres here in Dublin still use them.
You europeans have odd designations for them though, it's VNSP, NSP, MFL and WFL to me, I'm not sure where CP62 etc fit into that.
Sorry, waaaay off topic. |
|
|
| pinkmouse |
| quote: | Originally posted by imix500
...Then just wait till they all move! |
Time, about 1989, gig Bruce Springsteen at Wembley Stadium, (IIRC), rig, all Morpheus fully loaded prerig, (whatever happened to them?), location USL truss spot.
I climb up my ladder and get settled in, all running fine. Come the third number, the LD kicks in the moving lights, and they all do a sychronised pan from left to right. The whole truss swings backwards and forward about 2m, thanks to Newton's laws of motion. I almost fall out of my chair, and the rest of the spots miss the next two cues with my swearing... :) |
|
|
| pinkmouse |
| quote: | Originally posted by thevoice
...VNSP, NSP, MFL and WFL to me... |
Roughly, CP60, CP61, CP62, CP63 in your order...
Off topic? Perhaps, but I'm sure Mark won't mind. :) |
|
|
| imix500 |
| quote: | | all Morpheus fully loaded prerig, (whatever happened to them?) |
I have no idea. I'll run it by my bro who is a wiggle light tech.
| quote: | | thanks to Newton's laws of motion. I almost fall out of my chair |
Lol. Before the need for extra points for stabilization I guess! |
|
|
| Mark25 |
The question is: Is is safe to spread the 240v loads across the phases, or not?
feel free to discuss anything else too tho.....:) |
|
|
| juergenk |
in principle...yes, if the distribution is done 'to the rules'
for example, in Germany, domestic outlets must be fused by type-b circuit breakers
regards
Jürgen |
|
|
| pinkmouse |
| Is it safe - yes, as long as the kit is properly certified and maintained. Is it he way I would do it - no, for the reasons stated above. ;) |
|
|
|
