On Fri, 30 Nov 2018 07:35:24 -0000, FMurtz wrote:

Bruce Farquhar wrote:
Those cheap Chinese water heaters which are simply two plates of metal,
one on live and one on neutral, how can they work? Because the
resistivity of tap water apparently varies from 2 to 200 ohm metres.
That's a range of 100 fold in possible power output. I assume the
resistivity changes due to impurities like lime in hard water areas?

They used to make jug elements like that

And then the health and softy folk ruined it all.