Wire Discussion

[Pavan Dave]

On FIRST robots you are allowed to use different gauge wires for different motors depending on the amperage of the breaker protecting your circuit [speed controller, relay, RC, custom circuit, etc.].

What type of wire do you use (what gauge)? Do you stay consistent throughout your robot (Ex: X AWG wire for all motors, Y AWG wire for all sensors)? Have you ever calculated the power lost with lower gauge wires? Is there a reason for the gauge of wire you select? Have you ever tried to cut back on the weight of your robot by reducing the gauge of some wires? Has your team ever used a different gauge wire in the past and if so, why did they change?

[Joe Ross]

The price of copper drove my decision this year, and went with 12 awg. Prices more then doubled since I last bought it in 2006. Before that, we used 10 awg instead of 12 awg.

[sanddrag]

Wire prices sure have gone absolutely through the roof. We use 4ga ultra-finely stranded audio power wire for our main power runs from the battery and to the Rockwell block and breaker panels. We paid $6 per foot for it locally. It is available for about $3.50 per foot online. The 4 gauge is useful for the main power runs. With the kind of current FRC robots can draw, you can get a considerable voltage drop over 6ga (especially the low strand count wire they give you in the KOP).

We traditionally position CIM motors so we don't have to extend their wires. For power to the Victor speed controls we use regular 12 gauge power wire. On 500 series can motors we use 14 gauge zip cord and for spikes we use 18 gauge zip cord from McMaster.

On a related note, does anyone know why a good red (red, not pink) color wire is so hard to come by. Seems like more manufacturers are making it an off-red color that is closer to pink.

[Al Skierkiewicz]

Originally Posted by sanddrag

On a related note, does anyone know why a good red (red, not pink) color wire is so hard to come by. Seems like more manufacturers are making it an off-red color that is closer to pink.

Sanddrag,
I have noticed that the newer red color shows a distinct color change with temperature. (soldering) That may have been a design choice.

[Al Skierkiewicz]

Answering the original question...It depends.
I prefer to use #10 for all drive motor wiring. In general, we will mount the controllers for the drives near enough to the motors to use the supplied motor wiring directly to speed controller. We use #10 for any motor with higher current, Chalupa large and small, Fisher Price, etc. #18 power wiring for all Spikes not feeding motors, and larger if feeding a motor.
We will submit to using the minimum guage when weight is an issue, i.e. at the end of the arm last year or when the robot is really overweight and the lower guage won't affect performance. Sensors use #24 or #22 depending on where they are located and what they are used for. Wheel speed sensors that we have used in the past for crab drive, might get a #22 to connect to the drive module and then transition to a #24. Pots and switches get #24, since we use PWM bulk cable for wiring those devices. And of course, short pieces of #6 to connect the fuse panels, main breaker, battery and the Rockwell block.

[Mike AA]

Originally Posted by sanddrag

Wire prices sure have gone absolutely through the roof. We use 4ga ultra-finely stranded audio power wire for our main power runs from the battery and to the Rockwell block and breaker panels. We paid $6 per foot for it locally. It is available for about $3.50 per foot online. The 4 gauge is useful for the main power runs. With the kind of current FRC robots can draw, you can get a considerable voltage drop over 6ga (especially the low strand count wire they give you in the KOP).

We traditionally position CIM motors so we don't have to extend their wires. For power to the Victor speed controls we use regular 12 gauge power wire. On 500 series can motors we use 14 gauge zip cord and for spikes we use 18 gauge zip cord from McMaster.

On a related note, does anyone know why a good red (red, not pink) color wire is so hard to come by. Seems like more manufacturers are making it an off-red color that is closer to pink.

I am surprised you go to a larger main wire but for your drive victors you still only use the minimum. You could still get a good voltage drop on 12 if your motors are pushed.

-Mike

[sanddrag]

Originally Posted by Mike AA

I am surprised you go to a larger main wire but for your drive victors you still only use the minimum. You could still get a good voltage drop on 12 if your motors are pushed.

-Mike

We use 12 for its tighter bend radius and smaller size which allows us to route it more cleanly. Additionally, our power runs to the victors are quite minimal, some as little as 3 inches.