In 1987, the technical committee 17D of IEC drafted a technical document named "requirements for insulation coordination in Supplement 1 to iec439", which formally introduced the insulation coordination into low-voltage switchgear and control equipment. As far as the actual situation of our country is concerned, in the high and low voltage electrical products, the insulation coordination of equipment is still a big problem, and because the concept of insulation coordination is formally used in the low voltage switchgear and control equipment, it is only in the past two years. Therefore, it is an important problem to correctly handle and solve the problem of insulation coordination in products.

American cable branch box is a kind of cabled engineering equipment widely used in North American power distribution system. It is characterized by one-way door opening and horizontal multi-way bus bar. It has the advantages of small width, flexible combination, full insulation and full sealing. According to the rated current, it can be divided into 600A main circuit and 200A branch circuit. The main circuit of 600A is connected with screw in bolt, and the branch circuit of 200A is connected with plug-in connection, which can be connected with load. The cable joint used in American cable branch box conforms to IEE...

Abstract: insulation coordination is an important issue related to the safety of electrical equipment products, which has always been paid attention from all aspects. Insulation coordination was first used in high voltage electrical products. In China's electrical products, the accidents caused by insulation system account for 50% - 60%, and the concept of insulation coordination has been formally used in low-voltage switchgear and control equipment in recent two years. Therefore, it is an important issue to correctly handle and solve the problem of insulation coordination in products, which should be given enough attention. Key words: low voltage switchgear insulation coordination insulation material 0 Introduction low voltage switchgear

Under the cross sea bridge connecting Beilun District and Meishan island free trade zone in Ningbo, Zhejiang Province, six "power silver snakes" meander along the direction of Meishan island port area. In June this year, with the commissioning of the 110kV Qixing power transmission and transformation project, this cross sea power channel will provide continuous power to the port area.
In 2008, the State Council approved the establishment of Ningbo Meishan bonded port area, which is China's fifth bonded port area after Shanghai Yangshan, Tianjin Dongjiang, Dalian Dayaowan and Hainan Yangpu. In the same year, Ningbo Municipal Party committee and government made a decision on accelerating the construction of Meishan island.