Hi I have a problem with my Truma Ultraheat When I turn on the isolator master switch for the fire the rcd in my caravan trips but it also trips the site and my home rcd as well. One of the wires from the switch is white then via a male/female connectorer changes to a red lead. when I undo this connector all is ok. I think the red lead conects to the Elemet would this meen the element is fulty or could it be something else.