In my 1930 colonial brick home I have found rigid metal conduit running through the original section of the home. One of these conduits, containing one wire pair, runs up to the attic and out the side of the house into a conduit body. There, the wire loops outside the conduit body and goes back in. What function did this serve as it has no current when tested with electrical probe?

How large a conduit, Old Service?
Can you provide a photo?

I'm curious as well. A photo would be helpful.

Since it is still unidentified, be aware it may be switched from inside, maybe an outside light, and become live unknowlingly.

How large a conduit, Old Service?
Can you provide a photo?

Here is the photo

That is an old Conduit box. There was another piece of pipe screwed to the far end, at one time at least, and either probably had a light on it or was connected to a piece of pipe that brought power up to this connector. Easier than going up through the walls and floor. Look at the foundation wall below this to see if there is a mortared over hole.

In looking at the picture again, notice the grey stripe on the brick? Where does that come from? Could be a mark from an old piece of conduit.

I'm thinking Old Service. Can you see the conduit in the attic? can you see the same wires capped off in the Orriginal Panel? About what Gauge are the wires?
Or Light as mentioned?

After tracing it back down the rigid pipe and through a few closed junction boxes, the wire seemed to be making a home run to the original panel. I terminated the wire in the last j-box before the panel which enabled me to remove the rigid steel in the master bath and correctly slope the new plumbing work.
I think it must have been original service.

Good Deal, You could remove the old wires and use the conduit for satellite or something.