Posted By Matthew Herd Hi, I am what is called a 'production electrician' installing temporary power supplies from generators for corporate events in marquees and such like. I was wondering if there was any legislation directly effecting temporary power supplies and whether these should be tested in the same way as new installations in buildings? If for example I would need to perform an earth loop impedance test where would I find my regulation values of Zs for comparison? Would these be the same as in BS7671? I have a lot of questions about how much testing should be carried out on these supplies and have spoken to many people and still I cannot get a definite yes or no. Id be grateful if someone could offer some advice. My email is matthew.herd@mhtechnicalsolutions.co.uk. All comments appreciated.

Posted By Ken Taylor Basically, the 'Wiring Regs' are applicable to almost all installations whether permanent or temporary.

Posted By Mike Herbert I think there is another BS 7909 i believe that gives guidance for temporary power supplies to broadcast and entertainment. I forget its full name. There are always problems with these set ups such as caterers turning up with an extra 5kW urn that needs power and many other things related to technical equipment. Seperate phase for sound equipment from lighting and so on. Systems need to be properly designed to take account of situations like these. Hopefully you would be included in these decisions at an early stage. Testing the system from power supply as far as local distribution and making sure suitable RCD's are fitted is probably about as far as you can practically go before all the other contractors starting putting stuff into your system. As a temporary supply it is not viewed quite the same way as permanent buildings and requirements are sometimes laid out in public ents licence (if required) for the event. Make it as safe as you possibly can. Others further up the food chain will have to take responsibility for what comes after. Contact me direct if you wish. Hope this helps a bit cheers mike

Posted By Matthew Herd Cheers Mike, I had never heard of that BS. I now have a copy and am flicking my way through! Thanks to all for your help on this subject.