Hello. Does anyone have a fluke 1664fc tester, and have problems with it ? Most times I use it, it comes up with error message 5, which I think is interference on a circuit. Had the tester a couple of years now. Starting to wish a had bought a megger. It also trips rcds out, spoke to Fluke technical and their response was its a very complex tester, that's when technical is open, as apparently technical is closed on Tuesdays, as its the chaps day off !!!