Electrical tape may work on a single-wall rim, but because it's so stretchy, it'll deform into the spoke holes of a double-wall rim, allowing the tube to push into those holes and potentially burst. Instead of using electrical tape, you can use a tape with reinforcing strands. The type of packing tape with embedded strands has been used successfully in place of rim tape. Gorilla tape, gaffer tape, or duct tape would probably work in a pinch. These tapes might be messy to remove.