An ethic is framework, or guiding principle, and it's often moral. People with a strong work ethic believe that hard work is a good thing in and of itself.
A social ethic might include "treating people as you want to be treated." Used in the plural, ethics refers to the moral rules that you live by. You can use it generally, as in: "my ethics don’t include cheating." Or you can use it specifically, as in: "Slander and the running of negative ads do not seem to contradict the senator’s political ethics."