How to find heater wire cut?
Yes there are scanners that can read through concrete and even metal conduit, but they are expensive the one I use is a greenlee CS-8000, I just did a quick search and new these are ~750$. You may be able to find a used one for much less, these are awesome for finding a broken wire even in rigid metal conduit, through walls, identifying circuit breakers even if the power is off. There may be other brands/models out there but mine has saved me hundreds of hours and I have found faults that 2 electricians before me could not find , the difference was I have this simple but high accuracy tool.