The Line Inspectors' Association, Commonwealth of Australia was established in 1916 and registered under the Commonwealth Conciliation and Arbitration Act in May 1918. It was renamed the External Plant Officers' Association in February 1980 reflecting a change of membership from employees engaged in the Postmaster-General's Department of Civil Aviation as line inspectors, inspectors, and technical officers to employees engaged by the Australian Telecommunications Commission as senior line officers, principal line officers, external plant managers, and technical officers.

The External Plant Officers' Association was previously the Line Inspectors' Association which changed name in February 1980 to define the membership more clearly: employees engaged by the Australian Telecommunications Commission as senior line officers, principal line officers, external plant managers, and technical officers. In August 1991 the EPOA amalgamated with the Telecommunications Technical Officers' Association to form the Telecommunications Officers' Association which then amalgamated with the Communication Workers' Union of Australia in November 1992, eventually becoming the Communication Electrical Electronic Energy Information Postal Plumbing and Allied Services Union of Australia (CEPU) in August 1994.