Chris_H Posted February 7, 2004 Share Posted February 7, 2004 hey quick few questions if anyone has any answers, much apreciated 1.Can you hang lights off of an access tower(15ft)at the back of an auditorium?2.If 1 is possible do you have to earth the tower because of this? Thanking you Chris P.S. The company we've hired equipment from should be ashamed of themselves, we come to put 'that' last extension on and we noticed that there was bare flex coming out the back of the socket, ugh, then took the socket apart and the eart wasn't attatched <_< in the end, just because I felt slightly uneasy, I insisted that every bit of hired equip got checked out by the school sparky. Lost half a day, pratts. Link to comment Share on other sites More sharing options...
Andrew C Posted February 7, 2004 Share Posted February 7, 2004 1) Yes2) Hmm... Good question. "All extraneous metalwork...liable to become live in the event of a fault shall be earth bonded..." Paraphrased a bit from the regs. If it was me, I probably wouldn't bond the tower. My thinking is that the lantern may become live, but it's earth would provide protection. A bar hung on hemps is not bonded and we hang lights on them, whereas a PWB is. If you do try to bond it, you're going to need lots of links to connect all the bits together. The above is opinion, not gospel; however, All hired kit should be PATed prior to every hire. Moral of story? Use a different hire company in future. Link to comment Share on other sites More sharing options...
andystone Posted February 7, 2004 Share Posted February 7, 2004 It isn't a problem hanging lights of an access tower, but as with everything you should make sure that whatever bit you are attaching to is secure and you must have a secondary suspension, which ideally should be attached to a different part of the tower. You should also fit an earth bond, yes you could rely on the earth from the lantern, but what happens if the earth comes loose in the plug like your extension lead? In theory you should earth bond each part of the tower together, but generally it would be acceptable to put an earth bond on to any bit of metal to which a luminaire is attached and therefore there is a potential risk of electric shock if there is a fault. AndyStagetec Link to comment Share on other sites More sharing options...
Chris_H Posted February 7, 2004 Author Share Posted February 7, 2004 All hired kit should be PATed prior to every hire. Moral of story? Use a different hire company in future.I'd love to name and shame this company, but I wouldn't want to offend anyone that works for that company or be liable for somethihng like slander <_< thanks for the help though, most useful as usual Link to comment Share on other sites More sharing options...
sam.henderson Posted February 8, 2004 Share Posted February 8, 2004 I have been involved with loads of shows where they have hung lights off a access tower and it had been fine. Not sure about earthing though. SAM Link to comment Share on other sites More sharing options...
Ike Posted February 8, 2004 Share Posted February 8, 2004 Firstly dont be too quick to blame the hire company. I once got a shock of a multicore hired off a very respectable company, the mutlicore had been inspected prior to it leaving the warehouse however had been damaged in transit. It just goes to highlight the fact that a PAT only means the item is safe AT THE TIME OF TEST. Im not saying the item was tested before being sent out, its just it could well have been. As for the earth bonding I would say its probably not required. There is no possibility of a single fault on a lantern causing the scaffold to become live as it would require the protective conductor to fail and a live conductor to come into contact with the case. If an exposed conductor caused by a damaged cable was to make contact with the tower it is likely that the earth path through the hook clamp, lantern and the lanterns protective conductor would be good enough to trip an mcb or blow a fuse within a 'safe' amount of time for 10A dimmers (im assuming that is what is in use). Ike Link to comment Share on other sites More sharing options...
robloxley Posted February 8, 2004 Share Posted February 8, 2004 As for the earth bonding I would say its probably not required. There is no possibility of a single fault on a lantern causing the scaffold to become live as it would require the protective conductor to fail and a live conductor to come into contact with the case. If an exposed conductor caused by a damaged cable was to make contact with the tower it is likely that the earth path through the hook clamp, lantern and the lanterns protective conductor would be good enough to trip an mcb or blow a fuse within a 'safe' amount of time for 10A dimmers (im assuming that is what is in use).However it's not inconcievable that a number of faults might be present concurrently, and given that bonding the tower would cost very little and would be extremely simple and quick, and that there is a risk of someone being in contact with the tower (unlike the hemp bar) when a fault might occur, I'd suggest it would be pretty sensible to bond it. Link to comment Share on other sites More sharing options...
Ellis Posted February 9, 2004 Share Posted February 9, 2004 ABTT Training course: Fundamentals of Electrical Installation - Warwick, August 2003 I clearly remember that we were taught that you should earth bond the tower. If you were running your cables over another tower, that should also be earth bonded lest the sheathing misht become damaged. Link to comment Share on other sites More sharing options...
Ike Posted February 9, 2004 Share Posted February 9, 2004 I wasn't saying that it wouldn't be a bad idea to bond the tower I was simply saying that is probably doesn't need to be. If you do bond it to earth use the same earth as any exposed metalwork near the tower is connected to or connect that to the tower as well. Link to comment Share on other sites More sharing options...
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