Quote Originally Posted by Davek0974 View Post
Great, I'm aiming for a down draught table as I really don't like water in the shop ;)

and the the ground lead - ground the slats or to the workpiece??
Down draught is not without complications. Try drawing it remembering that you have to support the slats so they can support the sheet, parts will try and disappear if you give them any hiding place, the sparks have compressed air behind them and are about as obedient and obliging as a pyroclastic flow.

Why do you want to decide where to connect the plasma ground now? There is a big difference between a nice new shiny plate and that old lump of iron you found in the back of Granny's shed.