In my location it's required to have transformer plugged to a GFI outlet/circuit. When at the home giving estimate do I take along a GFI circuit tester and actually try and trip the circuit, if the oulet I'm plugging into is not GFI. That way homeowner is there and can track the GFI whether in kitchen, garage, or basement. Could prevent damage if freezer is on GFI circuit. Please help & give your methods.