A-TP12*
Sub-Committee T.P.-12—Electrical Grounding Practices
At the call of the chairman the above subcommittee met at the Mellon Institute of Industrial Research in Pittsburgh, Pennsylvania, on February 8, 1949. A list of the committee membership, indicating attendance at the meeting, is attached.
The committee was appointed to discuss corrosion problems arising from positive polarity grounding of d-c supply equipment and to make recommendations on the subject. The question arose because of a recent trend toward positive grounding of rectifiers supplying mine traction systems. In many quarters it was believed that this practice would lead to a difficult electrolysis problem on underground structures in the vicinity of the mines.
Following is a summary of the discussion along with the resulting recommendations:
It was developed that d-c street railway systems as well as interurban lines have been operated for many years with grounds on the negative side of the supply at...
