[jhill0914]

We are looking at adding several LED indicators to our robot, and I'm leaning toward putting together a small custom circuit to control them. It would consist of a FET for each LED, with the drain and source connected to 12V and GND and the gate connected to a DIO. I was going to breadboard it with all of the FETs, LEDs and current-limiting resistors on one board, with 12V and GND connected to the PD with a 20A breaker. Total current draw will be <100mA.

Reading through the rules, R40 talks about wire gauging - specifically stating that you must use 18AWG wire for the 20A circuits. It also has the following note:

"The branch circuit may include intermediate elements such as COTS connectors, splices, COTS flexible/rolling/sliding contacts, and COTS slip rings, as long as the entire electrical pathway is via appropriately gauged conductors."

I'm not really sure how to interpret the last statement - 'appropriately gauged conductors'. Do they mean that the entire circuit must be able to withstand 20A, or that your conductors must be appropriate for the calculated current draw of your circuit? Obviously there is a big difference between 100mA and 20A, and making the entire custom circuit out of 18AWG wire would be a pain. I would like to run the 18AWG wire to my breadboard and use much smaller wires on the board itself, but I don't want to have that rejected by the inspector at the competition. I'm sure this issue has been dealt with before by other teams, can anyone provide some insight into this?

Thanks
Jeffrey Hill
Mentor, Team 2930 - Glacier Peak Taterbotz