If the dryer had a 4 wire pigtail installed, the frame would not be connected to the power ground.
But you are all ignoring the first question, is it better to have a 4 wire pigtail and I said yes, for safety reasons. It is ALWAYS best to tell anyone what is best and WHY.
Sure in many cases I run across a 3 wire pigtail and the customer deals with it rather than spend the extra money for a 4 wire connection to the fusebox.
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