Re: Advice on mains current sensing, safely
The posh answer is a hall-effect current sensor plus associated electronics. However, if the TV really draws that much current, you could probably just put a series resistor in the mains supply, and apply the voltage across the resistor to a bridge rectifier and then a relay coil - a 5 or 6 volt type ought to be OK. Calculate the resistor value to give enough voltage drop across the relay when the TV's drawing current.
This will only work if the TV's current draw is fairly constant. If it varies a lot, you may well need a shunt regulator (zener plus power transistor) across the relay coil.
Cheap and cheerful, but it might just work.
Chris
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