I want my circuit to be isolated but I can't connect primary of transformer to grid because I can't afford 10Amps going through.
A transformer pulls only a small magnetizing current (a few percent of the maximum load current) when it has no secondary load.I can't connect primary of transformer to grid because I can't afford 10Amps going through.
There is no reason for your voltage measurement to draw 10 amps, even if that is the rating of your power source. For example, if I measure 240 VAC with my digital voltmeter across a 30 amp source my meter does not dissipate 7.2 kilowatts.I want my circuit to be isolated but I can't connect primary of transformer to grid because I can't afford 10Amps going through.