Copper and aluminum are not directly welding, not welding, but welding after electrochemical reaction occurs, will be out of danger!! For the transition piece, is the principle of weld formation in aluminum alloy.
" Electric equipment installation engineering code for construction and acceptance of bus device" in specific provision: the bus and the bus, bus and the branch line, busbar and electrical terminals lap, the lapping surface treatment shall comply with the following requirements:
( 1): copper and copper in outdoor, high temperature and moist or on the bus has a corrosive gas, indoor, must tin; in the drying chamber can be connected directly.
( 2) aluminum and aluminum: direct connection.
( 3): copper and aluminum in a dry room, copper conductors shall be tin. Outdoor or indoor air relative humidity near 100%, should adopt the transition plates, copper end of tin.
Accordingly, copper cable with aluminum cable connection can be used when the copper-aluminum connecting pipe, copper and aluminum wire cable connection can be used when the copper terminal, terminal shall be copper tin etc..
Along with the electric power system in aluminum instead of copper to increasingly grow in quantity, then appeared copper contact office due to corrosion caused by poor contact, fever, sparking, resistance increase and lead to equipment accident, increase the number of repair, affect the safe operation of the bad phenomenon.