Will the wire gauge in Ethernet cable suffice for firing the solenoids?
What gauge is the wire? R57 specifies 28 gauge minimum for PCM Solenoid outputs.
I don’t have the answer you’re looking for, but may I ask why you want to do this? 
Nicely organized, protected cabling for long runs?
Organizing wires
Cat 6 is 23awg, so that should work. Right?
This will work. Though I suggest getting a higher quality Ethernet cable that is stranded (flexible). Most Ethernet cables are solid core and do not like a lot of flexing.
Ethernet cables run about 22 to 24 gauge.
We made our own PoE cable for the radio this year out of stranded Ethernet cable and it came out really nice.
Let us know how this works out… Should be nice, especially when running multiple solenoids in the same area…
Love good cable management.
Good Luck,
Aloha!
Wouldn’t wire color be a problem?(R59)
Would it suffice to collie just the ends?
No
All non-SIGNAL LEVEL wiring with a constant polarity (i.e., except for outputs of relay modules, motor controllers, or sensors) shall be color-coded along their entire length from the manufacturer as follows:
Would the PCM not be considered a relay module?
No, the polarity of the PCM outputs is constant, so it is not exempt from this rule. “Relay module” refers to something like a Spike, which can output two different polarities.
I feel like this is something that could just as easily be accomplished by heat shrink. Whatever floats your boat I guess. ¯_(ツ)_/¯
Be sure to look at the definition of SIGNAL level (R57).
No need to worry about color for that.
R57
SIGNAL LEVEL circuits (i.e. circuits which draw ≤1A continuous
and have a source incapable of delivering >1A, including but not
limited to roboRIO non-PWM outputs, CAN signals, PCM
Solenoid outputs, VRM 500mA outputs and Arduino outputs)
28 AWG
(29 SWG or .08 mm2
)
Not really sure why this was bumped. But since we’re here, did you end up doing it? My team did this in 2015, and we were pretty happy with the results.