Rb20 Starter Question

[dtowngoalie]

Motor is a rb20det, car is a 92 s13 coupe. I have a 0 gauge wire connected to my starter solenoid which is directly connected to the battery, then theres the little like 14 gauges wire that tells the solenoid to activate. Theres another terminal like the one that has the large gauge positive wire hooked up across from it. It has a nut on it, but no wire connected to it, should this have a ground wire attached to it or no? I'm seeing a spark between the starter and block when my buddy first trys to start the car?