even so, the plug/socket should not overheat.that is caused by bad connection/s, either between the plug and socket, or the terminations into the socket, mainly caused by either poor quality items or wear through excessive use.It is, but this was during the initial heat up phase from cold, so the heater was running full time to get the water from 18°c (current tap water temp) to 38°c Takes a little over 30minutes to get a 1°c increase in temp so it has to run for around 12-15hrs flat out from cold. Once its at temp it will just idle between the hysteresis points.