Sect. 3. Interpretation
...
"eligible employee" means a unionizable employee other than a member of the management of an undertaking...

Sect. 4. Definition of management.   An employee shall cease to be an  eligible employee and become a member of management if the employee:
(1) is empowered to make management decisions;
(2) is entrusted with personnel management and industrial relations functions; or
(3) reports directly to the Chief Executive:

Provided that where there is a disagreement on the point when an eligible employee becomes a member of management, the matter shall be referred to the Minister for resolution, subject to appeal to the Court.

[Zambia, Industrial and Labour Relations Act, 1993, as amended by the Industrial and Labour Relations (Amendment) Act, 1997]

Sect. 3. Interpretation:  ..."managerial employee" means an employee whose contract of employment requires or permits him or her to hire, transfer, promote, suspend, lay off, dismiss, reward, discipline or adjudge the grievances of other employees, or to make direct recommendations on these matters to the employer;

Sect. 5 (1)   ...every employee shall have the following rights -

- the right, if he or she so desires, to be a member or seek office in a trade union;

- where he or she is a member or an officer of a trade union, the right to engage in the lawful activities of such trade union for the advancement or protection of his or her interests;

- the right to take part in the formation and registration or certification of a trade Union;

Provided: managerial employees shall not have these rights in regard to a union that represents non-managerial employees;...

[ILO draft provision for a Member country]

Section 328. Directors, managers, or administrative officers of a company may not be members of its trade union. Neither can those carrying out the tasks of direction, inspection, security, supervision, or audition, when these are of a general nature or related directly to work accountable directly to the employer.

[Dominican Republic, Labour Code, 1992]

Section 363. Employers occupying trust positions cannot belong to the same trade union as those who do not. The trade union regulations may determine the conditions and the rights of those members who are promoted to a trust positions.

[Mexico,  Federal Labor Law, 1995]