A few years ago, we experienced a severe cold snap. I remember reading a newspaper article about a homeowner using a welder to thaw out the house water pipes. Unfortunately, the house caught on fire. The insulation ignited because of excessive heat on the bonding jumper which was connected to water piping system. The heat was caused by extremely high current from the welder induced on the bonding jumper going back to the neutral in the service panel. The recommendation to avoid such a situation was to disconnect the bonding jumper before thawing out the pipes.
