Rough testing of device isolation

[orion242]

I have a device that I would like to just do some rough and ready testing of its isolation.  In a nutshell its a 2x RS-485 to Ethernet bridge.  Internal construction looks nice, has isolation slots in the pcb, they paid attention to track clearances, etc.  This device is using a pair of ADM2483 (assuming they are real) as the 485 transceivers.  Because the device is so cheap, I'm wondering if the transceivers have any isolation or not.  Not really concerned with super accurate measurements, more a yes it can handle 500v or she smokes < 100v.

Current idea is to put a Fluke 1507 across the 485 RX/TX terminals and its power input and see what happens from the lowest test voltage up to 500v and maybe right up to 1kv.  See if it survives afterwords or if "she pops".  This would be with the unit disconnected and powered down, only connected to the 1507.

So the question, would testing it this way give any rough idea of the isolation or a complete waste of time?  If not, what would be a rough test setup without $10K of gear?

Trying to wrap my head around the ADM datasheet and its maximum ratings as well.  If I'm reading this right (likely big IF), it can handle 2.5kv rms for 1 min.  Max working insulation voltage, I assume this is in operation which I will not be testing.  Input to output test voltage 1050v. Assuming that is more or less what I'll be pushing with this setup and I should see something close to insulation resistance listed  of >10^9 @ 500v.

Am I off in the weeds or on the right path to at least see if there is some isolation on this device?

TIA!