Darkfold Posted April 25, 2005 Author Share Posted April 25, 2005 We have to access the installed bars by ladder so changing the gels/lamps is a right pain in the arse. Normally I just tell our maintainance dept who are insured to 'go fetch' do the work on the ground, and then get them put back up. Pointing them has to be done from the floor (in theory). Usually I just get a ladder and do it on the quiet. Which dimmers are good for single phase permanent installation? Is £700 a reasonable price to set aside for getting a digital desk? Or should I be going more budget than this? Also, thanks to everyone who's helped so far ;) Link to comment Share on other sites More sharing options...
sam.henderson Posted April 25, 2005 Share Posted April 25, 2005 An ammount for the lighting desk depends how many channels of dimming you are going to go for, and if you have plans to ever hire in Moving Lights or more dimmers. Sam Link to comment Share on other sites More sharing options...
Jivemaster Posted April 25, 2005 Share Posted April 25, 2005 The booring but essential bit is the planning of the structure, Power, Hanging points and access. Without these you will be a statistic not a toaster. A ladder is not an appropriate work platform for frequent work at height, a ladder is officially a means of access to a work platform. As you are dealing with children with little work experience you should be planning an extremely safe and compliant (law etc) place and system of work and certainly you should NOT teach (even by example ) the use of bad practises. Link to comment Share on other sites More sharing options...
Darkfold Posted April 25, 2005 Author Share Posted April 25, 2005 Probably gonna play safe with the dimming and install only the number of 2500Watt channels that can be run at full power without overloading our current supply since the average rigger is 16 and has no clue about maximum loads, knowing the calibre of people I trained under. I try to teach em good now, but some people just dont learn... Which means 6 channels at the back of the hall and 12 at the front. Check my maths please... 63amps*240Volt=15120Watts at the rear of hall. 15120/2500=6 dimmer channels Front of hall: 32*4amps=128amps 128*240=30720Watts 30720/2500=12 dimmer channels. (hopefully this is about right and I havent been really stupid somewhere) I can then use some of the spare outlets to add portable packs to since I can work out whats on the permanent dimmers and add extra lights up to about 10% below max power draw. RCB's are fitted to all the power outlets allready. That got done 2 years ago as did a test on the wiring. The installed stuff looks to be fine as they overspeced when it was installed the first time round. The permanent bars are linked down to a patch area by lectriflex and each socket on the bar can handle 15amps. I will have a quiet poke around and see if I was fed a load of bull about no three phase, although I doubt it has been installed as the school is a small independant (350 pupils) in a village 3 miles from the nearest town. I have to be seen to be buying lanters as that is about the drama 'director' understands, he cant see why you shouldnt multigang the hell out of every socket you see... Directors, I ask you ;) Should I see about getting the school to buy a tower system then? Would that be a law compliant access method for rigging? If not, what is? Link to comment Share on other sites More sharing options...
bruce Posted April 25, 2005 Share Posted April 25, 2005 I will have a quiet poke around and see if I was fed a load of bull about no three phase, although I doubt it has been installed as the school is a small independant (350 pupils) in a village 3 miles from the nearest town. <{POST_SNAPBACK}> I'd be very surprised if you don't have 3 phase coming in the door. It's what the power companies will usually deliver as standard to anything bigger than a normal house. In fact, my mate's house, for some unknown reason, has a 3Ph supply. It's also what farmers want, so being in the countryside isn't an issue. Of course, the fact that you've got it coming in the door doesn't mean that it'll be available where you want it ;) Look for the main building fuse board. Is the main breaker really 3 breakers tied together? Are there labels on the board saying L1,L2,L3 or R,Y,B? None of these prove anything conclusively, of course, but they may give hints. Looking at the main electricity meter should tell you.... ps - DON'T TOUCH!!!!! that is about the drama 'director' understands, he cant see why you shouldnt multigang the hell out of every socket you see. Show him something like http://homepages.strath.ac.uk/~craa79/fs1.jpgandhttp://homepages.strath.ac.uk/~craa79/fs3a.jpg and he might take the hint. (yes, I know I've posted these here before.) Bruce. DISCLAIMER. The incident referred to above may not have been caused by an electrical fault. There was no forensic info, and the building was too dangerous to investigate properly. Nevertheless, the smart money is on an electrical fault.... Link to comment Share on other sites More sharing options...
Neil Posted April 25, 2005 Share Posted April 25, 2005 Should I see about getting the school to buy a tower system then? Would that be a law compliant access method for rigging? If not, what is?<{POST_SNAPBACK}> Well, after my school received our new Health and Safety regulations last week, I can now tell you that anyone who is under the age of 18 and has not received the correct training is no longer allowed on any structure over the height of 8 foot. This has meant that our school now has a redundant bantam tower, and 6 impatient lighting techs trying to work out how to reposition light for a concert in two weeks. It's just kra-zee. Neil Link to comment Share on other sites More sharing options...
Darkfold Posted April 25, 2005 Author Share Posted April 25, 2005 I'm ok on it then, as I'm over 18 and can twist arms quite well to get training ;) I'm off to have a look at our main distro board then tomorrow. As for power rating, what kind of cable supply do I want to ask for? Giving room for some expansion. the cable will have to travel about 50m underground to get into the hall and I hope they made cable access easy for themselves or its gonna be one hell of a job :D Do you need special termination boards before running 3phase into a dimmer rack? Sorry if thats obvious, but I dont have any experience with 3phase ;) Time to go learn me some... Link to comment Share on other sites More sharing options...
SparkySteve Posted April 25, 2005 Share Posted April 25, 2005 50m down the way or 50m across the way?? ;) Link to comment Share on other sites More sharing options...
James Posted April 26, 2005 Share Posted April 26, 2005 RCB's are fitted to all the power outlets allready. That got done 2 years ago as did a test on the wiring. The installed stuff looks to be fine as they overspeced when it was installed the first time round. The permanent bars are linked down to a patch area by lectriflex and each socket on the bar can handle 15amps.<{POST_SNAPBACK}> Um, Do you mean MCBs or RCDs? (Miniature Circuit Breakers) or (Residual Current Devices) Your maths is fine but it needs to take into account what is upstream of the sockets. For example I have visited more than one venue where there are 4 32A sockets available on stage each with their own MCB in the stage consumer unit but when you go upstream you discover that the stage is only fed via a 50A mcb. Try and look elsewhere to see how other people address the problems. For example my old secondary school had two 100A feeds to the stage, each feeding a consumer unit. There were 3 installed act 6 dimmers and 6 extra 63a sockets. yes there was scope to overload the supply but if you can't demonstrate competancy and understanding then get away from the dangerous equipment. these aren't toys. Oh I hope I didn't read Usually I just get a ladder and do it on the quiet. correctly Please don't be stupid. Working at heights by yourself is totaly stupid as well as being in breach of the 1974 health and safety at work act. OK, In answer to your question I would recomend you contact stage electrics, white light, ac or any of the other major installers, get them to specify and recomend an instalation. By all means create a specification for them to work by beccause if you start specifying items, particularly electrical connections and if someone has an accident in the future then potentialy you could be held lible. Given the problems currently faced by minors at school being unable to prove competancy to work at heights I would strongly recomend you look at asking for quotes for accessable rigging systems, winched bars for example that would allow students to get some experience of rigging lights on bars. As Paul Need said you can easily hire lanterns, you will find it a lot harder to hire instalation components. James Link to comment Share on other sites More sharing options...
Darkfold Posted April 26, 2005 Author Share Posted April 26, 2005 Ok, I'll try and pursuade the school that it's necessary to get a company round to do a professional spec and install it, as I really want this to be useable by people who havent had a huge ammount of prior training. Found out that we do have three phase running into the school (got hold of the site electrician, not his supervisor) and that although it would be possible to install a three phase supply, we dont have a conduit so it'll need a lot of digging... (50m horizontal distance ;) but underground not 50m straight down and then hang a left *DOH!*) Link to comment Share on other sites More sharing options...
Jivemaster Posted April 26, 2005 Share Posted April 26, 2005 Target the £4K end of the budget range. sketch some designs then pass these through the school to local and national theatre fitters aiming to spent about £2.5K on installation £1K on luminaires and £500 on training signage etc. Ensure that the bars will carry the intended loading Moving mirror and moving head lights are HEAVY -- easily 40kilos There's no point in hiring or buying yhem if you cannot hang them. Get the finished design framed and securely fixed to the wall so that future users will have the facts to hand --all the amps, kilos and metres. then people can always check that their design will hang on your rig Link to comment Share on other sites More sharing options...
bruce Posted April 26, 2005 Share Posted April 26, 2005 it'll need a lot of digging... (50m horizontal distance :P but underground not 50m straight down and then hang a left *DOH!*)<{POST_SNAPBACK}> Perhaps off-topic, but we install a fair amount of underground services - mainly data cables. But the installation cost will be comparable. The cost varies depending on whether it's a "hard dig" or "soft dig" - ie concrete/tar or grass, and on whether there are any road crossings involved. The last one I did, which was installation of dual duct, about 100m long, mainly soft dig with 4 manholes and 1 major road crossing, averaged out at about 60-70 pounds per metre, which is not unusual. That, of course, is just for the duct. You've then got to put cable in it. Power ducting tends to be more expensive than other ducting, as it's usually (but not always) deeper. Bruce. Link to comment Share on other sites More sharing options...
Darkfold Posted April 27, 2005 Author Share Posted April 27, 2005 It's gonna be nasty digging. The distro room is in the middle of a (listed for walls and exterior) building and it has to go out of the building (god only knows how...) across a hard dig of about 15-20 metres and then more hard digging inside the hall to get to the store room. PE are going to flip because it may involve digging up the floor of the hall... I have to 'Talk' further with the headmaster and see if he is willing to do it or not. I have a nasty feeling he's going to have a fit when he sees how much it's gonna take to do this :P ;) :P Link to comment Share on other sites More sharing options...
paulears Posted April 27, 2005 Share Posted April 27, 2005 does it have to be buried? I see loads that are wall fixed. They don't look too nice, but seem very common. Link to comment Share on other sites More sharing options...
Jivemaster Posted April 27, 2005 Share Posted April 27, 2005 So that's why they said there wasn't three phase! Maybee they had thought about that before, and decided against. 100a single phase is workable you may be stuck with that, as it seems the entire budget may be used running a new feed, then you couldnt use it for lack of lanterns!! Link to comment Share on other sites More sharing options...
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