s buckley-jones Posted May 2, 2016 Share Posted May 2, 2016 Moderation: Something in your image selection is broken! This is what happens when you don't have full control over the install and you engage the wrong people. viewing left to right . back stage call speakers , 18 ways of dimming , DMX cables com system wired in singles to all points ! and then the cat 6 backbone . yes there is a "power tray " with space . but this was part of the specialist systems so had to go there . and they wonder why I split . Link to comment Share on other sites More sharing options...
MarkPAman Posted May 2, 2016 Share Posted May 2, 2016 Link's not working ................... Link to comment Share on other sites More sharing options...
s buckley-jones Posted August 16, 2016 Author Share Posted August 16, 2016 this is the link link As I now longer have an association with this project , which a year on still has not finished snagging . Not a firm of consultants or architect fit for working on any theatre building . Link to comment Share on other sites More sharing options...
david.elsbury Posted August 16, 2016 Share Posted August 16, 2016 Ok? I really don't see too much of an issue? Link to comment Share on other sites More sharing options...
Gareth A Posted August 16, 2016 Share Posted August 16, 2016 My main comment would be lack of separation between AC and Data. We normally work on 300mm separation minimum between AC and Data. Quite bad practice as that try I would guess is 150mm tray. Link to comment Share on other sites More sharing options...
david.elsbury Posted August 16, 2016 Share Posted August 16, 2016 Was this a brand new build, or a refurb though? So many unanswered questions, amidst what seems to be a poorly worded and thought out tirade? We can't possibly see or know the whole picture just from one photo. And I'm sure you'd all agree that (if it is a refurb) best practice is sometimes unattainable? Link to comment Share on other sites More sharing options...
s buckley-jones Posted August 16, 2016 Author Share Posted August 16, 2016 Was this a brand new build, or a refurb though? So many unanswered questions, amidst what seems to be a poorly worded and thought out tirade? We can't possibly see or know the whole picture just from one photo. And I'm sure you'd all agree that (if it is a refurb) best practice is sometimes unattainable? this was a new build / refurb . yes it was a "vent" that's why the doc put me on the pills as another causality of burn out we just could not get the point across to the contractors despite the fact there was space on the power tray ,. because was deemed part of the specialist systems aspect of the project the dimmer cables had to go in that tray despite quoting uk lx regulations and good practice . as for the wording never was a word smith been on the tools all my working life. It is with regret this is most likely this is the end of my theatre career and you'll never work in this town again . Best that can be said Scotland's oldest theatre will continue working . if you thinking of engaging the design team responsible don't ! they're understanding of theatre complexes is poor Link to comment Share on other sites More sharing options...
alistermorton Posted August 16, 2016 Share Posted August 16, 2016 this was a new build / refurb . OOI which was it - new build OR refurb? Can't be both. EDIT : So from rereading (with my eyes open, which often helps) it appears this was a refurb in an old, established theatre, NOT a new build. Link to comment Share on other sites More sharing options...
sandall Posted August 21, 2016 Share Posted August 21, 2016 From (good & bad) experience of new installations in new & old buildings, if you are not across the electrical spec at the drawings stage you are probably doomed. Unless the electrical contractors have done performance-spaces before (unlikely, as they probably wouldn't be the cheapest quote), they will neither understand nor care about your concerns. Even if they do, their sub- (probably sub-sub-) contractors can still turn a properly spec'd system into a total dog's dinner, which needs ripping out & starting again, but by then of course both time & money have probably run out. I still can't see your image, but your description suggests that the wiring spec was poorly written. Were your consultants theatre people, or just friends of the architect? Link to comment Share on other sites More sharing options...
bigclive Posted August 21, 2016 Share Posted August 21, 2016 It's good to keep a modest separation between power and data/signal wires. More so with low level signals like microphones. But I get the feeling that in many instances the vicinity of the cables is used as an easy excuse for fobbing off unresolved audio issues that in reality have nothing to do with the vicinity of the cables. Of much greater concern is the "neat" installation of data cables that just about breaks every rule of maintaining cable integrity. Tightly bunched cables with sharp bends for instance and also kinks and crush-damage during installation. Keep in mind that in the touring industry it's not uncommon to have pre-made looms combining dimmer multicores and data lines in one bunch. Sometimes I think that many of the electrical regulations and guidelines were written by people with no real-life experience in the electrical industry, and then enforced religiously by equally incapable people. Link to comment Share on other sites More sharing options...
paulears Posted August 22, 2016 Share Posted August 22, 2016 I suspect the same - years ago, every book prescribed never running mains and audio cables next to each other, and spent ages talking about ideal crossing angles and the matching physics. Then every PA snake had a mains cable attached to it, with never an issue. Has anyone ever measured the actual leakage between a bit of mains cable and audio or data cable in the vicinity? With the parallel running of both live and neutral, is there really very much of a field around a mains cable? I think I've come to the conclusion that it's the connection to ground that causes most grief - and just last week I found that Tecpro systems are extremely unhappy with circulating ground current when sticking a loudspeaker station in a rack. Comms system grounded from the PSU stage left, speaker station stage right and all hell breaks loose. The unbalanced comms feed that runs parallel with Socapex and TRS for long stretches surely would be a good place for dimmer spikey interference, but this doesn't happen. Two grounds on the other hand wrecks it. Can I ask a question - with cable trays, is there a rule/reg/requirement for specific separation written in any document that has to be conformed to, or is this just a good practice thing? Link to comment Share on other sites More sharing options...
Junior8 Posted August 22, 2016 Share Posted August 22, 2016 It's good to keep a modest separation between power and data/signal wires. More so with low level signals like microphones. But I get the feeling that in many instances the vicinity of the cables is used as an easy excuse for fobbing off unresolved audio issues that in reality have nothing to do with the vicinity of the cables. So true. In the last build I was involved with we are able by being involved early on to keep all the low voltage analogue, audio and data completely separate from the mains and particularly the dimming obeying all the then good practice guides and there was still one annoying fault we could never really track down. I don't think how we did it added much to the cost but looking back I do wonder if it was a waste of time considering how trouble free stages full of mixed audio and mains tripe often seem to be!!! On Paul's query I remember asking that at the time and I don't think there was. Link to comment Share on other sites More sharing options...
pmiller056 Posted August 22, 2016 Share Posted August 22, 2016 There was/is a requirement in the 'Wiring Regulations' aka BS7671 to physically segregate mains power (and live stuff directly derived from mains power) from telecom, fire alarm and other small signal stuff. I can't remember the wording of the requirement is/was because it is a long time since I've been involved in such matters. The intent is to ensure that low voltage stuff that would be safe to directly handle remains safe and cannot become live, even under gross fault conditions such as building movement or fire. Link to comment Share on other sites More sharing options...
sandall Posted August 22, 2016 Share Posted August 22, 2016 I suspect most of us grew up learning at our mother's knee that having mains anywhere near low voltage was "a really bad thing" & have never really questioned it. On one refurb I did, the local "expert" forecast total disaster because I spec'd line & speaker feeds in 2-compartment steel trunking!! Paul is right in that line & neutral magnetic & electrostatic fields will largely cancel out, though induced high-frequency s*** on the line may not, but if you think inverse-square law there isn't going to be much field left once the separation exceeds about 1/4-inch, which is largely taken up with the insulation. Link to comment Share on other sites More sharing options...
dbuckley Posted August 22, 2016 Share Posted August 22, 2016 Has anyone ever measured the actual leakage between a bit of mains cable and audio or data cable in the vicinity? With the parallel running of both live and neutral, is there really very much of a field around a mains cable? Remember Future Film Developments? They had, back in the day, a cable in their range intended for camera use, and it had a few coaxes, a couple of balanced audio, and mains in one jacket. The catalogue described a test they performed with a light bulb at the far end of 100m of cable, dimmed to 50% using a triac dimmer, and they measured the crosstalk to the audio pairs. I cant recall the level, but it was pretty low. Link to comment Share on other sites More sharing options...
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