Depends on the company. I've had companies do this for me. In one large company I won't name, the way we did it was to have someone with enough authority give

Depends on the company. I've had companies do this for me. In one large company I won't name, the way we did it was to have someone with enough authority give me a statement in writing acknowledging that anything I made outside of business hours, using my own computing equipment wasn't owned by the company. That was good enough for me.