A bussbar is used as a termination or connecting device for motor leads and jumper cables inside an outlet box.
We use bussbars made of copper. Most bars are 1/4" thick. Often they have a straight, "L", or "U" shape depending on the lead connection requirements.
Some typical applications may include: Ridgid power lead termination or connecting medium between lightning arrestors, surge capacitors, and the motor leads in the outlet box.
The bussbar may be attached to accessory devices, or to a bussbar insulator.
Graphical reference part 20 page 13 of NEMA MG 1-1993.