There is nothing in legislation specifically disallowing people from working more than one job, including being self-employed. Nor is there anything generally limiting the maximum hours they can work. Some industries have regulations around continous hours and forced breaks, for example driving/transport, but generally if people want to work 14 hours a day, they can.
It is however, commonplace for employers to include clauses in Employment Agreements limiting staff's abilities and freedoms in this regard.
Generally speaking imposing these restrictions has to be reasonable and justified from either a business interests or Health & Safety point of view. An employer needs good reason and to be explicit about what the restrictions are and why.
Legitimate business reasons might cover issues like; Intellectual property protection, confidentiality of commercially sensitive information, conflicts of interest and non-competition.
Health & safety reasons would include the avoidance of employee fatigue and burn out particularly with physically demanding jobs.
Grounds of reasonability for restrictions of secondary employment vary of course in case by case. For example it would be harder to reasonably justify precluding a part time employee from engaging in a second job over the same restriction for a full time staff member.
Aside from any explicit clauses in the Employment Agreement there is an underlying duty of fidelity and loyalty inherant and expected in an Employment Relationship. Staff are expected to give their employer full efforts and loyalty. Anything which could damage the employer's business in this respect could be argued to constitute a breach of fidelity, and could justify termination of employment and compensation accordingly.
Relying solely on good faith and the expected duty of fidelity is often not enough to protect the Employer's interests alone, and we do strongly recommend the explicit inclusion of any desired restrictions in Employment Agreements.
Ensure you have these in yours by using our latest
Employment Agreement templates, and if you believe you require more than the standard protection get in touch with our team for advice.