You really need to put a known load on the meter and then see what it reads. If it was a DC ammeter there would be other ways to do it, but AC is trickier.Is there another way to test short of just putting it inline? I dont have any of the equipment suggested.
A regular 1-1/4x1/4” glass body fuse will work for this purpose since they are rated 250V.For your voltmeter you will be making connections to 120 or 240 Volt. I would recommend a fuse in the wires to the Voltmeter. A 1A fuse should be enough provided it has sufficient breaking capacity, ie rated at 240Volts AC or higher.
Cut a piece of clear plastic (I recommend polycarbonate for this) maybe 1/16” or so thick, mount it a little bit above the fuse panel on standoffs. This is assuming open fuse holders, no need if they’re the panel-mount round insulated kind. The plastic panel might save your azz someday if something comes loose in the control compartment.Thanx for all the input guys! I very much appreciate the suggestions.
I will install a 4x glass fuse panel inside the breaker box tomorrow for the voltmeter and hobbs. I ran new 8ga leads from the genny to the breaker box thru the amp meter. Yes, I use quality copper crimp-on lugs anywhere possible.