My shower unit, a Triton Rapide 1, has started smoking after about 5 minutes running. The smoke comes from the plastic cover on the live (brown) wire going into the thermal cut out. The wire is getting exceedingly hot.
What might be causing the wire to heat up? And how might I fix it?

Paul, September 2009

Power down. Remove the wire. Clean the ring terminal and terminal using glasspaper. Refit the wire and tighten the screw fully.

garryk, October 2009

A wire will get hot if it takes too much current -or- if a contact point is dirty (often through sparking when not properly tightened) a high resistance joint acts as a localised heater. Sparks over time build up a layer of soot and the little heater becomes ever more efficient.

If a joint has a resistance of just 1 ohm the power dissipated at a dirty junction in an 8.5kW shower is a frightening 1.3kW (Power Watts = I² R)

Given that the breaker has not tripped I suspect the second reason - but I just guess.

To be fully compliant with safety rules and common sense a qualified electrician might be best.

Peccavi, September 2009