Difference between Section 25F and 25N
The difference between Section 25F and 25N is that the former applies to companies with fewer than 100 employees, while the latter applies to establishments with more than 100 employees. As per Section 25F, when the notice required to retrench the workmen is one month, an establishment that employs more than 100 employees should give three months' notice to retrench the workmen. Another important difference between these two sections is that an establishment employing 100 or more employees cannot retrench employees without permission from the appropriate government. However, an establishment not covered by Chapter VB (i.e., an establishment with fewer than 100 employees) need not wait for permission; just an intimation to the appropriate government is sufficient.
An establishment in construction activity comes under "factory" for the purpose of Chapter VB, and therefore, three months' notice to retrench the workmen is required anyway.
Section 25O and Construction Companies
However, Section 25O, which provides procedures for closing down an establishment, does not apply to companies engaged in the construction of buildings, bridges, roads, canals, dams, etc.
In practice, a construction company should employ workers on a fixed-term contract basis so that employment naturally terminates automatically when the construction work is completed. In such a situation, no compensation, notice, or notice pay is required to be given to any employee.