I am rigging up a portable test panel, will be using a true-meter APM that will do up to 600 VAC or 600 VDC. I would like to be able to use it to measure typical U.S. 120 VAC or 240 VAC and 480 VAC. Looking for recommendations on how to build a simple economical circuit such that a fuse would blow if input voltage exceeds ~500 VAC or 500 VDC.
For 480 VAC, is that RMS so would peak voltage be 679 V and would that matter or make things more complicated in building a fuse-able circuit that would trip? The sole purpose being I'd rather blow a $1 fuse than my $70 volt meter.