computer Posted March 3, 2004 Share Posted March 3, 2004 Hi, I need a temporary truss or whatever to hold about 8 parcans, 2 scanners, dimmer packs (small 4 channel ones) and some various bits and pieces. It needs to be standard height designed for a medium sized hall... probably 3m max. it needs to be about 5-6m wide, and have good support for all these things. we will either hire it for 3 days (fri,sat,sun) if possible for a temporary weekend event or if cheap, buy it... any ideas? computer PS: bit like http://custom1.farnell.com/cpc/product.asp...uct%5Fid=266349 but bigger and sturdier Link to comment Share on other sites More sharing options...
Wilf dLampy Posted March 4, 2004 Share Posted March 4, 2004 Assuming there isn't an option of rigging said truss from the roof, I'd suggest 2 manfrotto wind up stands and a length of slick or trilite trussing. More detail on the exact weight loading (how much for each item, roughly where it's going on the truss) would be helpful in determining whether the stands and truss are rated for the load, but assuming your "various bits and pieces" aren't too heavy....... Link to comment Share on other sites More sharing options...
computer Posted March 4, 2004 Author Share Posted March 4, 2004 nm, I have managed to borrow some stands that will do what I need for free... thanks though... Link to comment Share on other sites More sharing options...
Chris Higgs Posted March 4, 2004 Share Posted March 4, 2004 Would this not make the load you could carry on the truss virtually nil?If the Manfrottos still have a 36kg SWL, by the time the truss/brackets self weight is subtracted there won't be much left. Link to comment Share on other sites More sharing options...
Ike Posted March 5, 2004 Share Posted March 5, 2004 Would a trilite goal post type setup with outriggers not be better? Link to comment Share on other sites More sharing options...
Wilf dLampy Posted March 5, 2004 Share Posted March 5, 2004 Would this not make the load you could carry on the truss virtually nil?If the Manfrottos still have a 36kg SWL, by the time the truss/brackets self weight is subtracted there won't be much left.I was going with the 6m trilite weighing about 20kilos (looking now at opti's website gives me a figure of 16.74kg for a 6m length, but I'd have used two 3m- because they can be transported without the need for a truck- so add a bit on for joiners...)That leaves 15kg ish for a couple of parcans, small scanners. I guess this all highlights the need with rigging to look at the exact situation before deciding on a solution (as Chris so rightly teaches). In this case I had an image in my mind of what this rig would look like- based on the equipment I use, not necessarily the equipment 'computer' has to rig. Link to comment Share on other sites More sharing options...
Big Dave Posted March 5, 2004 Share Posted March 5, 2004 The other thing you must remember to factor in the the weight of cables that have to go on the truss as this can actually represent a significant part of the load. Link to comment Share on other sites More sharing options...
Ellis Posted March 8, 2004 Share Posted March 8, 2004 If the stands have a 36kg SWL each, and you have a 20kg truss, 10 kg can be considered to be on each stand, leaving a total of 52 kg for lanterns (uniformly distributed). That's a fair few par cans. Make sure you earth-bond the stands though! Link to comment Share on other sites More sharing options...
ianl Posted March 8, 2004 Share Posted March 8, 2004 Make sure you earth-bond the stands though!does anyone really earth bond lighting stands supporting tempory truss??????? I have never seen a manfrotto or powerdrive stand earth bonded, for that matter I don't think I've ever seen a temporary truss hanging on motors earth bonded either Link to comment Share on other sites More sharing options...
Ike Posted March 8, 2004 Share Posted March 8, 2004 Anything uninsulated and conductive that may become live in case of fault should be earthed for reasons of safety, however, in my opinion other precautions should be made to prevent the stands becoming live. These include through inspection and testing, covering of sharp edges and otherwise protecting the cable. If reasonable steps have been taken to prevent cable damage and the use of unsafe electrical equipment I would have though the need for equipotential bonding is questionable. Link to comment Share on other sites More sharing options...
TomLyall Posted March 8, 2004 Share Posted March 8, 2004 er, how would you earth bond such an item? is it just a case of putting a plug on the earth bonding wire (connecting only earth obviously, and probs using CEE Form or osmething)? or do you get some fancy connectors? Link to comment Share on other sites More sharing options...
Ike Posted March 8, 2004 Share Posted March 8, 2004 The problem with plugs is that people tend to unplug them. If you have to use one cover it in lx/gaffer tape and label it as with something like "PROTECTIVE EARTH CONNECTION. DO NOT REMOVE." The idea of equipotential bonding is to connect all exposed conductive parts together so there is no voltage between them. There is no point bonding one bit of metalwork to the consumer unit earth and not bond a bit of metal 100mm away. It is also of limited use to connect various exposed parts within arms reach to earth via different paths. If you were going to bond the stands in question you should also bond any radiators, metal pipework, metal window frames, structural steelwork etc that are within arms reach to the same place. Link to comment Share on other sites More sharing options...
Jivemaster Posted March 8, 2004 Share Posted March 8, 2004 If there are appliances on the truss each should be earth bonded via its cable and should clamp onto the truss with a screw so would the truss be earthed any way? Link to comment Share on other sites More sharing options...
Ike Posted March 8, 2004 Share Posted March 8, 2004 While it would be earthed I'm not sure how great the loop impedance would be, especially if you are talking about a phase conductor contacting a stand supporting a bit of trilight with the lanterns on. EDIT: just thought: If the appliance is atached to a bit of temporary truss does the bit of truss then become part of the appliance in the eyes of the IEE/BSI or am I taking this way too far? ;) Link to comment Share on other sites More sharing options...
Chris Higgs Posted March 20, 2004 Share Posted March 20, 2004 With my trussing (specifically Slick since it was mentioned) hat on, please do not use lighting stands to support trusses over about 3m long or without some effective means of either secondary support or kentlage.The stand/span/load argument is valid, but the stability of the structure is the essential feature to consider. I believe there is no requirement to 'bond' a lighting stand if the installation is fully in accordance with the wiring regs. The ABTT has advice on this specifically.(I should know more than I do, since I sit on the committee - I will find out) Link to comment Share on other sites More sharing options...
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