Delta wired gfci

[Mikelite68]

I’m a marine electrician. I was recently working gfci circuits on a vessel that where wired in delta. Gfci is wired with 60v on each leg. When checking the gfci with a tester it showed an open ground and tester would not trip the gfci. There is 120v with meter and test button on gfci itself works properly. Gfci is grounded properly. I’m wondering if the tester is only made to work on y wired system with a hot and nuetral rather than delta with two hots? Thanks for any clarification.

 

[Dennis Alwon]

The tester needs a ground reference

 

[don_resqcapt19]

Many marine systems are ungrounded systems, and so a plug in type tester will not trip the device, as Dennis said. The same thing happens where an replacement GFCI is installed on a circuit that does not have an EGC....there is no path for a plug in tester to create a ground fault to trip the device. However, while the GFCI should function correctly where supplied by that system, I doubt that it was tested and listed for use on such a system.