This is the 18399th most frequent Russian word.
электромонтеры
Electricians specializing in electrical installation and maintenance.
The word 'электромонтеры' refers to the subject of the sentence—technicians specializing in electrical work performing an action.
Электромонтеры ремонтируют электрическое оборудование.
Electricians are repairing electrical equipment.
The word 'электромонтеры' again serves as the subject, indicating professionals who performed the installation.
Вчера электромонтеры установили новые светильники.
Yesterday, electricians installed new lights.
Here the word 'электромонтеров' functions in the plural accusative case as the object of the action—those who are being requested to perform the task.