i do not know. it was a very well made vintage IEC that i found when we cleaned out my mother's husband's junk stash. i clipped off the IEC termination and was very pleased of what i found when i stripped it; a very nice (IMO) shielding layer of cloth and metal mesh. it went directly on one of the spare power supply modules i culled from one of the two additional 1500s i obtained a long time ago for spares for my legacy example, and placed into said unit. i was going to just snip off the ground lead, but then i decided to terminate it with a spade and earth it on a sandwich of steel washers mounted on a vertical plastic shaft near the rear wall, for what that's worth. anyway, at least it LOOKS like it's serving a purpose...