Electric strings are ball end like acoustic strings, so they'll physically fit most steel-string acoustics. They're designed to work with a magnetic pickup, though, so on an acoustic they generally produce less volume and less warmth than bronze acoustic strings. Their lighter gauges can also change neck relief, so you may notice changes in action or buzzing.
If you're reaching for electric strings because acoustic strings feel too heavy, try a lighter acoustic set instead. Our Phosphor Bronze line goes as light as .009–.046 (P946 Ultra Light), with .010–.048 (P1048 Extra Light) just above it.
A classical guitar is built only for nylon strings. Steel strings of any kind can damage it.