ECN Forum Forums General Topics of the Trade General Discussion Area Can't Identify this Connector

I'm trying to find the other half of this connector. If you can't read the plate,it says 323-N 3P 4@ 100A 600V.

However, it sure looks like it only accepts 3 conductors plus ground. I don't know what this is and my electrical supplier has been "looking into it" for me for two days but no luck yet.

Any info appreciated.