Judges of the superior court may grant writs of injunction:
1. When it appears that the party applying for the writ is entitled to the relief demanded, and such relief or any part thereof requires the restraint of some act prejudicial to the applicant.
2. When, pending litigation, it appears that a party is doing some act respecting the subject of litigation, or threatens or is about to do some act, or is procuring or suffering some act to be done, in violation of the rights of the applicant, which would tend to render the judgment ineffectual.
3. In all other cases when applicant is entitled to an injunction under the principles of equity.