That asphalt stuff isn't quite inflammable, it stands pretty high temperatures under fault conditions. That stuff was definitely used for residential/commercial 220/380V lines well into the 1950ies. Our main appartment feeders in the house are pulled in such conduit, at least partially. Some of that stuff has been replaced with PVC flex and new color coded wires. However the electrician told us we'd have to upgrade them in the near futuure due to new requirements (60A 3ph service for 9 appartments, still beter than the old 20ies 25 A DC service)
