Dual shielded 3 core 4mm sq power cable

[Subbu68]

Yes these are pure copper US & IEC connectors. I imported these from Singapore.

just noted that you are using US Type B plugs. Are you using this in India with 240V supply? They may fail for a surge since these are rated for 120V use. If they are not tested and marked for NEMA / IEC wouldn't use them.

And these do not seem to be standard US plug. Type B has a round earth as per NEMA not a U shaped one. some of the surface area for earth terminal is lost.