I have had an electric shower for several years which has suddenly stopped working. I am getting power to the shower as the red light comes on, but when I turn the shower on the red light goes out and there is power travelling down the neutral line. It is a 8.5kw shower run with 6mm cable - there seems to be some burning on the neutral wire at the 45amp switch - do I need to replace the wiring as I have replaced the switch with no effect.