Believe it or not, this pipe (first 2 pics from top) that had been beaten up and pulled far apart was still live. Those wires between the two pulled apart section of pipe were very live when we got up there. Amazing.

The pipe we ran was set off the surface of the roof and attached to wooden blocks that are eventually painted to retard water seepage and then glued down to the roof. I learned a long time ago NEVER EVER shoot a screw into a sealed flat roof. This piping was to provide power for an additional down-spout de-icing cable that needs a dedicated GFCI circuit.

Also, you can't see it here, but whenever I run conduit outside like this I always pule and additional grounding conductor for a redundant grounding safety measure. The Chicago and National Electrical Code don't require it in this situation; the metallic pipe itself provides the ground. But I have seen too many situations where the pipe has rusted away or been banged apart or subject to some type of physical damage, which separates the two pieces, breaks the metallic continuity and therefore compromises the integrity of the grounding. It is only a small additional investment to pull a dedicated grounding conductor along with the power wires you are pulling anyway. I think all electricians should do this.