practice without specifically being hired?

There is a reason for Job Description, nursing and maintenance are very different and I always let nurses, maintenance, activity, dietary, housekeeping, imaging... review their job descriptions on an annual basis. I have always on each annual review kept their job description to review...it is an eye opener to see how much people do and are responsible for. I would not feel comfortable working in maintenance even though I am a licensed Nurse give an injection, it just would not happen, it is called boundaries and I appreciate my license and plan on keeping it in good standing.

Another issue:

If a person is not hired as a nurse, that means he/she has not gone through orientation and skills check offs that must be done to determine that he/she is competent to function as a nurse. Just because one is licensed does not mean that the employer isn't liable for determining that nurse's competence and training on that employer's policies/procedures, equipment, etc etc etc.

This is one time my state's nurse-practice act isn't annoyingly vague.

In AZ, the nurse practice act allows you to do any procedure you've been trained to do, that your employer's policy and procedures allow you to do, that hasn't specifically been ruled on via an advisory opinion by the board.

So, in AZ - even though a nurse would be trained in giving injections in nursing school, if they're employed in the maintenance department, it's highly unlikely the employer's policy and procedures allow them to give injections.

Your scope is limited by both training and your employer's written policies. It can also be expanded if the employer provides additional training and has a written policy allowing that procedure - I.e. - inserting picc lines, etc.