All employees will fall under one of the above laws about conditions of employment. Many employees fall under more than one of these laws.
The laws work in order of priority. For example, if a Bargaining Council Agreement (or other centralised collective agreement) covers the work done by an employee, then that Agreement applies to that employee. If there is no Bargaining Council Agreement, then you must see whether a sectoral determination or Wage Determination applies. If no Bargaining Council Agreement or sectoral/Wage Determination applies, then the BCEA will apply, unless they are specifically excluded by the BCEA.
An individual contract of employment may override the Basic Conditions of Employment Act provided it is definitely more advantageous for the employee and provided it does not affect certain ‘core’ rights which are identified in the Basic Conditions of Employment Act. These core rights which cannot be changed be agreement, include normal working hours, regulations applying to maternity leave, sick leave and annual leave, and the prohibition against the employment of children amongst others.