Grounded conductor. Theory verses reality. At the panel the grounded and grounding are equal potential. At the receptacle with no load they are equeal. When a load is applied between the hot and the grounded the grounded conductor becomes hot for half of each cycle.
When the refrigerator would run the grounded conductor would have a different potential from the grounded box. This would allow for an arc, from the grounded to the grounding.
This came up at a training session when an inspector (multi-hat) asked why he sometimes got zapped touching a white, i.e. grounded wire.
