nikkicallaghan Posted September 15, 2015 Share Posted September 15, 2015 In my local amateur theatre a load of strand preludes have been bought second hand. They've been rewired by one of the guys in the theatre but after trying them today they don't seem safe. Should they have been rewired by a qualified electrician or can anyone do them. Link to comment Share on other sites More sharing options...
Dmills Posted September 15, 2015 Share Posted September 15, 2015 No need for the formal qualifications (End of the day you are wiring up a lightbulb for gods sake!). The kit needs to be safe, and there should probably be some system of inspection and testing in place (PAT being the usual approach), it comes down to the old 'competent person' chestnut. What exactly is wrong with them? If you can identify a safety problem on a quick visual inspection while preparing to use the thing then the correct response is to NOT use the faulty item until someone can sort it (Same as you would do for any electrical appliance even if it was brand new out of the box). Regards, Dan. Link to comment Share on other sites More sharing options...
nikkicallaghan Posted September 15, 2015 Author Share Posted September 15, 2015 1442349854[/url]' post='527665']No need for the formal qualifications (End of the day you are wiring up a lightbulb for gods sake!). The kit needs to be safe, and there should probably be some system of inspection and testing in place (PAT being the usual approach), it comes down to the old 'competent person' chestnut. What exactly is wrong with them? If you can identify a safety problem on a quick visual inspection while preparing to use the thing then the correct response is to NOT use the faulty item until someone can sort it (Same as you would do for any electrical appliance even if it was brand new out of the box). Regards, Dan. On visual inspection they looked fine it wasn't till I was focusing one and there was a big flash followed by the lamp blowing. The next unit in being powered up gave out a big burning smell once again followed by the lamp blowing. Opened both units up and there was live wires touching the case. As you can imagine I've condemned them all until I can check them. The guy who rewired them admitted he's not done a safety check after rewiring but still put them avaliable for use Link to comment Share on other sites More sharing options...
emsgeorge Posted September 15, 2015 Share Posted September 15, 2015 Has he used the correct cable ? Or has he used normal pvc, which would melt off within mins on a high temp lighting fixture like a prelude ? I have seen people 'rewire' and have no concept whatsoever that the unit gets to ridiculous temperatures very quickly, and so you need very high temp cable to cope with it. Link to comment Share on other sites More sharing options...
nikkicallaghan Posted September 15, 2015 Author Share Posted September 15, 2015 1442351135[/url]' post='527668']Has he used the correct cable ? Or has he used normal pvc, which would melt off within mins on a high temp lighting fixture like a prelude ? I have seen people 'rewire' and have no concept whatsoever that the unit gets to ridiculous temperatures very quickly, and so you need very high temp cable to cope with it. The internal cable wasn't pvc but had been wired so badly when you touched the focus knob the wires were pulled tight and working their way out of the connectors. To me the cable going in the lamps doesn't look like fifteen amp cable which our rig is looks more like lightweight five amp. Lesson learned I've condemned all the units till I can find the time to sort them out and will never trust units I don't know about in future Link to comment Share on other sites More sharing options...
Jivemaster Posted September 15, 2015 Share Posted September 15, 2015 " they don't seem safe " is a very poorly reasoned argument, the description of the mode of failure is much more helpful. They should be rewired by a competent person, that person may or may not be an approved electrician. The repaired items should be inspected and preferably tested to PAT standards by another competent person. Link to comment Share on other sites More sharing options...
nikkicallaghan Posted September 15, 2015 Author Share Posted September 15, 2015 1442352797[/url]' post='527671']" they don't seem safe " is a very poorly reasoned argument, the description of the mode of failure is much more helpful. They should be rewired by a competent person, that person may or may not be an approved electrician. The repaired items should be inspected and preferably tested to PAT standards by another competent person. I see what you mean my original post wasn't very well worded apologies for that Link to comment Share on other sites More sharing options...
david.elsbury Posted September 15, 2015 Share Posted September 15, 2015 "To me the cable going in the lamps doesn't look like fifteen amp cable which our rig is looks more like lightweight five amp. " What lamps are fitted to your preludes? Unless you're lamping them around the 3.6kW mark I cant see why you need "15 amp cable" Link to comment Share on other sites More sharing options...
Jivemaster Posted September 15, 2015 Share Posted September 15, 2015 In amateur establishments there may be no pay, but there needs to be similar competence and confidence that professional establishments have, train and retest occasionally. However without the salary motivator you have to keep people's interest so some training may be a lot of help for the members and the club. Link to comment Share on other sites More sharing options...
nikkicallaghan Posted September 15, 2015 Author Share Posted September 15, 2015 I'm an idiot. They are actually quartet f units. God knows where I got prelude fromTraining has been mentioned and attempted in the past. The local pro theatre sent some people along to give a basic in flys/ lights and sound but it was poorly attended(mainly the people who wanted it didn't turn up)I ran a basic course in the use of our new lighting desk awhile ago and didn't have many there but the ones who came feel confident enough to use it now Link to comment Share on other sites More sharing options...
niclights Posted September 15, 2015 Share Posted September 15, 2015 650W @ 230v = approx 3A = 0.5mm2 cable. So technically you can have surprisingly thin cable. In practice it is more likely to be 1mm2 = 10A. Just make sure it's the correct type (ie. silicon) with no bare ends showing etc. Link to comment Share on other sites More sharing options...
themadhippy Posted September 15, 2015 Share Posted September 15, 2015 650W @ 230v = approx 3A = 0.5mm2 cable.But then we get into the rulze and find even though its a 650w load we may still need to use a cable rated for 10A or maybe more depending what the size of protective device is, or in regs speak, Ib ≤ In ≤ Iz Link to comment Share on other sites More sharing options...
dbuckley Posted September 15, 2015 Share Posted September 15, 2015 " they don't seem safe " is a very poorly reasoned argument, the description of the mode of failure is much more helpful. ... there was a big flash followed by the lamp blowing. The next unit in being powered up gave out a big burning smell once again followed by the lamp blowing. Yeah, seems about right... Link to comment Share on other sites More sharing options...
vinntec Posted September 16, 2015 Share Posted September 16, 2015 There are only three wires to connect up, two to the lamp base and one to the earthing point. So same level of knowledge to wire correctly as putting on a 13A plug. So most likely this part is OK. Much more likely is that they didn't use silicon (or some other high temperature cable) so that the insulation is burning off as soon as the lantern gets hot (and a Quartet F gets very hot internally) so bare wires appear and touch. They might also have forgotten to allow for the fact that the lamp unit has to be moved when focusing. So as soon as you try and focus, the cables stretch and give way. This is more a hazard to the user than to the lamp, which I would expect to still be in working order once the electrics are repaired (in most cases)? The casing of a Quartet is like a guillotine, so you have to take care when you snap it back together that you don't trap any of the wires between the two parts - which could cause them to break, or lose their insulation, even before the lamp is moved. So a live could then touch the casing which should trip the MCB (unless the earth wire is missing or damaged). Again this should not cause the lamp the fail in most cases. So this is a possible cause or contributory factor as now moving the lamp will stretch some of the cables even if slack was allowed for. Do you have any snaps of the internals of a failed unit? Certainly don't use any of them until they have been checked. It so happens that I had to rewire a Quartet F not long ago while changing the reflector, but I had our electrician safety check it before it went back into use. This is despite the fact that I would consider myself a "competent person" - but since I don't do this very often, it made sense to have it checked by someone else even more competent. Link to comment Share on other sites More sharing options...
xllx Posted September 16, 2015 Share Posted September 16, 2015 I sometimes freelance for a company that has an excellent policy on wiring lanterns or connectors. Nothing is ever wired up without a visual inspection by another person. Some of the guys are qualified electricians, some are like me, 30 year in the industry "competent persons". But the rule applies to everyone. This sort of peer review really helps with quality, a second pair of eyes will help pick up cables that are just a little too tight, or the stray whisker of copper not in a terminal. No one wants to have to rewire something and this peer review really does help to improve standards. Once you start doing this, it becomes second nature. Link to comment Share on other sites More sharing options...
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