Common ground between two circuits

Howdy

I have built the 10 Channel Light Bulb Sequencer circuit from the projects section in the forums and the circuit part works perfect. I was lazy and used a wall transformer to supply 12 volt but then when i attempted to hook up the triacs it would not work. I think the problem is the ground. According to the schematics there has to be a common ground between the 12v and 115v circuits. This is my first electronics project and i do not have infinate knowledge so here is my question. Can i still connect ground between the two circuits or do i have to make my own power supply? Do i have to make sure that the 115v house outlet is wired properly (Neutral/Hot)? I don't want to blow up my 12v circuit that would be bad. :roll:

Oh yeah and the schematic is missing a connection from pin 16 to +12v on the 4017 IC - makes odd things happen if its not connected.

Thanks,
John

OK well no one cares about my question so i said screw you guys and went ahead and put the ground in and it works perfect - parts are cheap anyway lol. Yay now time for great party lights Hmm.. still not sure about the physics of why it works and why it does not blow up the 12v circuit but thats alright don't matter.

Chow,
John