matt-the-dj Posted July 10, 2016 Share Posted July 10, 2016 Hi guys, Looking for some input from anyone that has knowledge of the sectional video walls power supplies.I was crewing at a gig in a marquee with a temp dis board on Friday and had all pa and lighting on the same supply as a 14 panel led video wall, There was a main rcd at the origin which decided just as the band went on to start tripping and not wanting to reset, I went through and removed bits of kit to see what was causing the issue as everything had been on from setup at 2pm with no issues, the only way I could get the supply rcd to hold was to unplug the video wall and I had no further issues from there.I am a qualified electrician who teaches the subject so please do not explain how a rcd works, my question is does anyone who installs the video know if they have an inherent earth leakage and if so, are they supposed to be on their own supply as I think I had no major fault but lots of little earth leakages adding to make enough to to take out the 30ma rcd?RegardsMatt Link to comment Share on other sites More sharing options...
jason5d Posted July 10, 2016 Share Posted July 10, 2016 We've had this issue, LED screen panel psu's leak earth a lot.We use breakers for big fan units so they go on and stay on. The breakers are, Hagar ndn116a d16 hope that helps Link to comment Share on other sites More sharing options...
Peter F Posted July 10, 2016 Share Posted July 10, 2016 if they have an inherent earth leakage and if so, are they supposed to be on their own supply as I think I had no major fault but lots of little earth leakages adding to make enough to to take out the 30ma rcd?RegardsMatt Hit the nail right on the head. Lots of switched mode power supplies, each adding a bit more leakage. Cheers, Peter Link to comment Share on other sites More sharing options...
matt-the-dj Posted July 10, 2016 Author Share Posted July 10, 2016 Cheers guys I thought as much.....I didnt get asked about power supply, next time if I hear " we have a video wall" ill ask for a seperate supply without sharing an rcd with me......thats the trouble with marquees, generally they are not wired by those that know. I prefer individual local rcbo protection, at least it is not then all on 1 rcd. We had alot of kit all on 1 supply, biggest shame of all though was we had hired a film crew when we heard there was a video wall being provided by the client, we couldnt use it. Link to comment Share on other sites More sharing options...
sameness Posted July 11, 2016 Share Posted July 11, 2016 Cheers guys I thought as much.....I didnt get asked about power supply, next time if I hear " we have a video wall" ill ask for a seperate supply without sharing an rcd with me......thats the trouble with marquees, generally they are not wired by those that know. I prefer individual local rcbo protection, at least it is not then all on 1 rcd. We had alot of kit all on 1 supply, biggest shame of all though was we had hired a film crew when we heard there was a video wall being provided by the client, we couldnt use it. Always RCBO per leg when doing power for LED screens. Even though the technology is getting better, a lot of the cheaper screens still leak plenty. That way, as you point out, you dont lose the entire gig. Link to comment Share on other sites More sharing options...
nickb12345 Posted July 11, 2016 Share Posted July 11, 2016 Never get the marquee company to do the power. There are plenty of decent event power companies out there who do this day in day out. Last marquee company I worked on a job with turned up with a whole box of widow makers! Nick Link to comment Share on other sites More sharing options...
badweasel Posted August 7, 2016 Share Posted August 7, 2016 Always RCBO per leg when doing power for LED screens. Even though the technology is getting better, a lot of the cheaper screens still leak plenty. That way, as you point out, you dont lose the entire gig. This is how you do it. PS The power supplies are not 'leaky' as such. Switch mode power supplies generate high frequency harmonic currents. This interference can affect other equipment on the same circuit. EMC standards require that these currents be filtered and shunted to earth. That's up to 3.5mA per device, so it's easy to see how a 30mA RCD could trip. Link to comment Share on other sites More sharing options...
StageSmarts Posted August 26, 2016 Share Posted August 26, 2016 The 'earth leakage' trip current for an RCD or RCBO may be a lot lower than the rated "30mA". The applicable standard EN 61008-1 states +0, -50% so it may trip at 15mA and still be within specification. With a class 1 device legally creating up to 3.5mA of 'earth leakage' you could experience tripping already with 5 devices plugged in. Now depending on the quality of the RCD (it varies a lot) you may also have some problems with transient 'earth leakage', very short bursts of higher current during switch-on. Well designed RCDs won't trip on those but some lesser types will. And always use "A" type RCD's - not the "AC" type as the latter may trip due to the non-linear current draw of switch-mode power supplies. Link to comment Share on other sites More sharing options...
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