hi i had a power shower fitted about 2 years ago by a qualified electrician everything worked to perfection until the shower started to cut off at the switch

I have removed the cover of the swith to check it out and found that the neutral wires are burnt about one inch from the connection inside the switch any idea what coused this?

Ross, April 2009

Obviously heat will have caused this and a resistive load will have generated the heat.

A high resistance junction in the switch may have been caused by tightening the screw terminal through the insulation of the wire or the screw may have worked loose over time as the switch was operated resulting in sparks and sooting on the conductors.

At 30 Amps a resistance of just 0.1 Ohm is 90Watts of heating at the junction - Power in Watts is current squared multiplied by resistance (P=I²R)

Peccavi, April 2009