Can you melt frozen pipes with a welder? What if they aren entirely metal?
Thawing frozen buried water lines with an arc welder has been done safely for years. It has to be done correctly. It is not a safety issue because of electrocution — the voltage is only around 15V — but because of the possibility of fire damage. As long as the pipe is a good conductor of electricity, the current will follow the pipe and not go into your home. The treatment takes only a few minutes. However, in your case the pipe has been replaced by plastic so that is not an option and could force current into your home. Some plumbers have equipment that will thaw pipes by forcing steam into one end. This can sometimes take several hours to thaw the length of the pipe with a resulting bill of a few hundred dollars. Call around to see if someone can do this for you. The only real solution is to bury your pipes deeper. Your local building code office should be able to tell you the recommended depth. It depends on your local climate. In the northern tier of the US that can be as deep as
