How long is the declaration period for temporary transformers in Hai 'an construction site?

Two years. According to the relevant public information query, the use period of temporary construction projects shall not exceed two years. If it is really necessary to postpone the use, it shall apply to the competent department of urban and rural planning 30 days before the expiration of the use period. Transformers are made according to electromagnetic induction. It consists of an iron core made of silicon steel sheet (or silicon steel sheet) and two groups of coils wound on the iron core.