another question on detatched building?

OK, I have a question on this panel. A detached garage, A four wire feed was run from the service panel to this panel in the detached garage. I say four wire but only three wires were used. The grounding and grounded wires were separated except for one neutral wire on the ground bus bar, probably added later. A bonding jumper is on the bus bar, defeating the purpose of separating the two wires. A grounding wire was run to a ground rod on the exterior of the garage. OK, Because only 3 wires were used, making it a 3 wire feed then the neutral and ground wires can be bonded, correct? The feed cable to this panel is a direct burial cable, no metal conduit. If I am correct then why separate the wires in the first place and why , if they ran 4 wires out didn’t they use all four?
The first four photos show the panel in the garage and the last photo is the main panel, showing the feeder cable to the garage.







It has the four wire feed. It should be corrected.

Jeffery, because there is a forth wire already there then you’re saying it should be used?


Thanks. Just curious, why do you think they didn’t use the 4th in the first place?

Laziness, or they just didn’t understand the concept of a four-wire feed. Who knows for sure?

Jeff is 100 % correct, If a 4 wire setup is ran then it must be used.