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Discuss elson opal double immersion water heater problem in the Electrical Forum area at ElectriciansForums.net

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Electrician's Arms
Hi all,

Was called out to check why 2 new immersion elements had gone. They both had been replaced recently.

On closer inpsection found the economy 7 immersion cable had melted and caused connections to melt and is irrepairable

Second peak immersion looked fine> Did a insulation resistance and got >500 megohms.

I noticed thermostat had been turned to full.

Could this be what damaged the element


If your customer lives in a hard-water region, where standard copper sheathed immersion elements were installed and the thermostat was set to >66°C (>150°F) would certainly be contributory factors in the rapid demise of the elements and excessive heating.
However, the usual suspects when the conductor/cable insulation melts or burns is a) poor termination(s), the Neutral seems to be particularly vulnerable, b) heat resistant flex has not been used, or c) conductor CSA inadequate. Often in DIY lash-ups a combination of all three.
I always use ring and pin terminal crimps for the element and thermostat terminations respectively in order to ensure a good, durable connection to the screw terminals. Alloy or titanium sheathed elements should be used in all hard-water applications.
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