Earth Resistance Measurement Problem

http://www.megger.com/us/contact/local/Index.php

If the tester has a manual voltage range, select higher voltages.

Why are you using Megger products? They do not support their equipment and generally they are not very good. Phone support is horrible if non-existent. They are either away on training/sales jaunts selling their products or off on sales junkets eating and drinking instead of paying attention to follow up for customer support on products they should be supporting. This is typical Megger. Their products do work, don't get me wrong, it's just that you can do better and get better support with other products.

Megger is like Levi, riding more on their past reputation than actually doing the job they were once known to do in the first place. Which they rarely do anymore.

Try using AEMC http://www.aemc.com/ For earth ground testing and electrical insulation testers. Nifty yellow pelican case and nice overall package.

AEMC is very good with phone support even on holidays. Excellent training and overall an excellent product compared to Megger. Send your newly purchased model DET4TC2 back and purchase AEMC grounds tester.