Ground fault electrical switching apparatus for coordinating tripping with a downstream ground fault switch

A ground fault electrical switching apparatus for interrupting current in a protected alternating current (AC) electric system, said electric system including a downstream ground fault switch, a power source, and a load, said downstream ground fault switch having a first ground fault trip curve, said ground fault electrical switching apparatus comprising:

• separable contact means of said ground fault electrical switching apparatus for interrupting current flow in said protected AC electric system when opened, said separable contact means connected in series with said downstream ground fault switch between said power source and said load;
• sensing means for generating at least an AC sensor signal representative of AC current flowing from said protected AC electric system to ground;
• ground fault trip signal generating means connected to said sensing means for generating at least a ground fault trip signal as a function of said AC sensor signal and a second ground fault trip curve which is different from the first ground fault trip curve of said downstream ground fault switch;
• and
• trip means responsive to said ground fault trip signal for opening said separable contact means.