I have installed several aftermarket ammeters in various cars and trucks I have owned. These were usually the Stewart Warner brand gauges with the standard two post arrangement. Power in on one side and all electrical loads on the other. If you wanted the gauge to monitor the device, it had to be hooked in series or it wouldn't affect the gauge. This meant, as pointed out many times above, that the poor old gauge had to carry the entire current load for the system.
I have various meters at work for checking current draw. They use a inductive pickup coil around the wire that senses current flow and displays it on the meter in amps.
Were any of the ammeters installed in the later model rigs of an inductive type...ones that didn't have to be wired in series and carry the full load...safer from a failure standpoint!
I personally have never had a ammeter fail, catch fire or short out, and don't believe I know anyone that has.
Stuart
