If a sub panel has neutral bar that is connected to the metal panel box, then this is generally considered an improper installation, but can be easily corrected. Many panels have this condition, however, under current wiring practices, it is considered safer to not have the sub panel box tied to the neutral bar, but to have the sub-panel properly grounded.
This concept, is that the neutral bar, in the sub panel, should not be connected to the sub panel box. If so, under some conditions, appliances (stoves, refrigerators, laundry equipment, etc.) may become energized and shock you.
Who to consult? An electrician.
Electricians can normally correct this condition very easily and quickly.