Ground
Ground turns up in 2 fields: powder coating, welding. Here is what it means to the people in each one.
Ground in powder coating
The electrical path from the part through hooks, racks and conveyor to earth that lets charged powder stick.
Electrostatic coating needs the part held at earth potential, and the usual safety requirement is 1 megohm or less from part to ground. Cured powder on hooks and racks is an insulator, so contact points build up resistance with every pass. Poor ground lowers transfer efficiency, causes uneven film, increases back ionization and can let a part hold a charge that sparks and ignites a powder cloud.
"Meg the hooks before we start, ground has been sketchy all week on line two."
Ground in welding
Shop word for the work lead and its clamp, which completes the welding circuit through the part.
Cable and clamp that connect the workpiece back to the welding machine, properly called the workpiece lead. It is not an electrical safety ground. A loose or rusty connection makes the arc erratic, a badly placed clamp aggravates arc blow, and a clamp far from the joint pushes current through bearings, chains or rebar in its path, so welders clamp it close to the weld on clean, bare metal.
"Arc's wandering all over, your ground is on the painted side of the table, move it to bare steel."