Core Balance Current Transformer : A ring-type current transformer in which all primary conductors are passed through the aperture making any secondary current proportional to any imbalance in current
Young & Company Electric Power Products and Related Engineering Services, Glossary of Electrical Terms, http://www.youngco.com/young2.asp?ID=4&Type=3, CA., USA 2001. (Electr Sfty - Amer) {514}