Support Craft 

Any construction trade other than a Union pipefitter, Union pipefitter welder, or even a Union Plumber.
A short list of support crafts include, but are not limited to:
Iron workers, carpenters, electricians, millwrights, laborers, sheet metal workers, operating engineers.

The iron worker realized he was just a support craft and started crying.

Support Craft by matt_the_plumber November 2, 2016