Final answer:
Non preference eligibles may be placed on a certificate when no preference eligibles are available for selection.
Step-by-step explanation:
Non preference eligibles are typically placed on a certificate when there are no preference eligibles available for selection. This means that if there are no candidates who meet the preferences and requirements specified for a particular position, non preference eligibles may be considered.
For example, if a job posting requires military experience and a preference for veterans, but there are no veterans who apply or meet the other qualifications, non preference eligibles may be placed on the certificate.
It's important to note that preference eligibles, such as veterans, have priority in the hiring process, so non preference eligibles would be considered only if there are no preference eligibles available.