Electricity

Electricity in the Worlds of Astrum Skies has a few peculiar traits. At large scales, it functions relatively normally, lightning strikes during thunderstorms and can be quite devastating in the proper conditions. At smaller scales, it becomes quite inefficient however. Metals can only conduct electricity when it comes in very large amounts, such as a lightning strike or a magic spell, but electricity cannot flow through most materials in smaller quantities.
This makes "human-sized" technology based on electronics physically impossible and has many implication for technology in the Worlds. As such, the advancement of technology has long ago reached a peak, and instead investment in the arcane magics has proven more beneficial to the Worlds.
Steam powered technology, while rare, is an example of some of the most advanced technology not based in magic that will probably ever exist. Combustion engines, while physically possible, are incredible rare as they are dependent on planets developing fossil fuels such as oil in very large amounts, a rare substance but valuable when found.
Since the space between planets is filled with a thin atmosphere, one noteworthy electrical phenomenon is Nebula Storms, which allow for large burst of lightning discharge in the dust clouds that float through the low gravity regions of space.

Meta

What this means for any narrative set in Astrum Skies is that technology levels in the setting is stuck in "medieval fantasy-ish" levels of technology. You won't find light bulbs or vacuum cleaners, and computers as we know them will never exist. While crude oil exists, it's just not likely given the incredibly specific requirements and millions of years it takes to form it and then the time it takes to find it. Steam engines are possible and used throughout the setting, but are rare as Astrum based magics can typically fill the needs of any kind of engine more efficiently. See Astronavigation for related information.