The accurateness of current clamps is restricted to roughly 1%, which negates the major benefit of the WT3000 (its remarkably high accuracy) but by using the SC1000 in combination with the WT3000 it is likely to attain accuracy levels downward to one part per million, says the business.

The SC1000 is supposed to be the first accuracy DC current transformer with a center that can be divided to permit installation on an offered cable or busbar. It is based on the zero-flux theory, in which the magnetic field around the prime conductor is balanced by the output current.

Refer : http://www.electropages.com/viewArticle.aspx?intArticle=9890