In most states, unless there is a morals clause under the terms of your employment, it is not permissible to fire you for legal actions done outside of the workplace. Typically, no, but it can also depend upon the type of work being done. An some cases it would be considered a breach of ethics to socialize with members of competing firms, particularly in such places as law firms.
no
Only eight hours
Yes.
If you mean can an employer compel an hourly employee to work without pay, then no, never. Hourly employees must be paid for all hours worked.
Yes an employer can deny giving you overtime hours but if you have already worked overtime then it is not okay for an employer to deny paying overtime once the hours have already been earned.
Only with the employer's consent.
1
No, not in the United States.
It would be a rare employer that does not have rules against it. However, as a contractor, you can independently state your hours and how you do your work.
You remind the employer that it can fire whoever it wants, but has noi choice about paying for all hours worked.
24 hours
I am interpreting this question as "can an exempt employee do 'off-the-clock' work for their primary employer? The answer to that is no. If an exempt employee is doing required work for the organization, it doesn't matter what time of day or night, or what day of the week that the work is being done. They are always considered an employee while performing a project or function for their employer company. The employee can, however, volunteer for an organization (non-profit for example) as part of their community service a group of co-workers from their regular employer. They would not be considered working in that case because it is not required and the employer simply supported the service activity. For instance, the employee joins a Habitat for Humanity volunteer team with others from their organization and they get hurt on the jobsite. This is not a workers comp claim because it was not a work activity. All work is done at the risk of the individual volunteer. If you are asking if an employee can work on an employer's site, on a non-work related project, and on a project that is not required... the issue is whether or not your employer is willing to allow you to use their office and resources for your project.