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Will it work to use 4 CT`s (one on each phase, and one on the neutral) and connect them to the GC-100?

No, they are not designed to be used this way. The problem with using four individual CT`s is the limited linear range of the CT`s. In this configuration you are depending upon the output of the three or 4 CT`s to ``add to zero`` over the entire range of current. If there is any distortion in the in the output of the CT it will manifest itself as a false ground fault current. The smaller the CT the lower the current will be when this distortion appears. In the residual system with the Electronic Trip circuit breakers we do have this configuration, however, these CT`s are fairly large and have been tested over the operating range. There is also a ``desensitization`` function in the trip unit which effectively increases the Ground Fault threshold at the higher current levels ( typically above 3x ) that is designed to fit the CT characteristics.

CTA-ID : 2013108
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