For 480V-AC circuits, usually 1kV-DC and sometimes 500V-DC is used as a test voltage—versus around 3 volts for the typical digital multimeter set for a resistance function. "Megg-o-Testers" are available roughly in the 100V to 5kV-DC range.
You can visualize a "Megg-o-Tester"
insulation-resistance test set as simply an ohmmeter with the equivalent of a high-voltage battery.
Producers of these instruments are AEMC, Megger, [formerly Biddle/AVO] Fluke and others. { Er, see
www.aemc.com ..
www.megger.com ..
www.fluke.com }
[This message has been edited by Bjarney (edited 04-04-2003).]
