I have a nice volt meter with AC current measuring installed on the boat.
I have dual 30 amp shore power.
I was thinking if you had a switch, you could toggle between sources.
The current transformer looks like a ring and I think it has an iron core wrapped with some small copper wire.
How would you make or can you buy or adapt some other coil to work?
I think the number of turns and wire gauge would have to be similar or the current measurement wont be the same.
$20 was the original cost so must be much lower or not worth the effort.
It's better to buy a current transformer and the correct indicator.
Current transformer every time must have a connected indicator, else he transformer will blow up and very high voltage will appear at the connections of the instrument.