Reverse polarity means connecting a power source, or polarised componenet, with the positive and negative poles the wrong way round. If the positive and negative supply is connected the wrong way round in electronic devices, it usually causes damage, because semiconductors are sensitive to polarity.f you connect the electrode holder to the positive post and the ground clamp to the negative post the curren … t flows to the base metal thru the ground clamp, across the arc, thru the electrode and holder and back to the machine. This is reverse polarity.