As the pump of our 4.5kW water heater started to make unusual noises, i removed the covers and the steerings cover, to find the heating element was connected to the contactor with totally rusty ferrules, one was just soldered and screwed in. so i removed the corrosed parts, cut a bit of the cable as there was enough spare, removed the insulation, to find all the copper strands were black. not overheated, corrosed. I decided to change the whole cable, traced it to a cover on the heating element, removed the cover to see this:
thanks pump for failing otherwise i'd never found this time bomb. imagine there were 4500W running on almost daily...
this is a three phase 400V-delta heater. i dont want to know if the heating element or the terminals were hotter when running...
i forgot to mention the age: 25 years. i'd thaught the corrosion protection would be a *bit* better, humm....
the wire under the green-yellow one is blue at the other end of the cable
i couldnt find out if the connections ever were made fine (ferrules or soldered wire), as i couldn't get the terminals open yet... the water is warmed up by our central oil heating in the winter, the electric heating is just needed in summer, but i think i'll just leave it that way and shut the electric part down.
I see what looks to be the slot in the head of a screw.
Look at the vertical channel of sorts running north-east/southwest.
It's definitely a screw - probably with a little pressure plate to clamp against the wire. You don't want to tin wires that go under a screw. The solder will "creep" and the connection will eventually work itself loose from heat cycling.
Re: Water Heater (German)#115700 12/07/0307:42 AM12/07/0307:42 AM