UL 508 A: Industrial Control Panels

UL 508A - Branch Circuit Currents

FLA and FLC as stated in UL508A


Each motor has two current values:

  • FLA: "Full Load Ampere", is the rated current of the motor, written as nameplate data and indicated in the NEC with the name "Nameplate FLC".
  • FLC: "Full Load motor-running Current", is a value of current chosen from table 50.1 of UL 508A. Given the motor power expressed in HP, the FLC represents the maximum current that can be absorbed by the motor in the worst case.

Each component of the branch circuit (conductors, fuses, circuit breakers, etc.), except for overload relays, must be sized focusing on the FLC; the reason is that, once the motor power is fixed in HP, the FLC represents the highest current that the motor rated at that power can absorb. Therefore, if the motor is replaced by another motor of equal power, it is not necessary to replace the other elements of the branch circuit due to a possible higher current absorbed by the load.

The overload relay, as its tripping characteristic is adjustable, must be sized focusing on the FLA .


Safety in Collaborative Robotics

There is no “Collaborative Robot”. That is one of the first statements you hear from people working in Collaborative Robotics. The reason is because the robot can be designed for a collaborative task, but it is the Application that makes the “Robot Collaborative”. The reference standard for Collabo