The speed of light is associated with both electric current and electromagnetic radiation. The commonality can be traced to the concept of velocity field, but only providing that space is densely packed with sinks and sources in a primary electric fluid that is the stuff of all matter. In this manner, electric current travels at the speed with which this fluid emerges from one terminal of a battery and re-enters the return terminal. Likewise, if the sinks and sources that permeate all of space are paired into rotating dipoles, then when a dipole is induced to angularly accelerate, excess electric fluid will spill over into the neighbouring dipole, and it will do so at roughly the same speed as that of electric current in a laboratory circuit. The on going propagation of this effect is electromagnetic radiation.
It is worth being mindful of the 1856 Weber-Kohlrausch experiment which was the first historical connection between electricity and optics. see,