Positive busbars, which collect all positive connections. Positive and negative busbars are physically identical apart from the red/black colours used by some manufacturers to visually differentiate between. Key Steps: When wiring a pair of 12V busbars, connect the positive terminal of each load to a stud on the positive busbar and their negative terminal to a stud on the negative busbar. Then, connect the positive busbar to the battery's positive terminal via a fuse and the negative one to its. When wiring Modbus RS485 devices, you will typically have two wires: a positive signal (A) and a negative signal (B).