Dear All, Just a bit of assistance needed please as I can not find the answer? I have been asked, if we use 3 phase in the workplace and in racked units, should we put warning signage up for this? I have not come across this before other than warning signage for possible electric shock. Any assistance is more than welcome. Many thanks, Dave

No requirement for any signage over and above that you would have for single phase, as line to earth voltage is the same whether it's single or three phase. An awful lot of commercial and, most industrial properties have 3 phase supplies. Take any large hotel, they will have a 3 phase supply. No additional warning notices. Anyone working on the electrical system would not require a warning label to tell them that the supply is 3ph, and if they do, throw them off site never to return because they are not competent to be working there! ;)