Request a Re-Write of the Wire Color Rule for 2013.

[BigJ]

Based on the rule, I think I can wire the whole bot with everything black, and be legal?

The positive lists "black with stripe" so solid black for both wouldn't be sufficient.


I think the color lists exist mainly to help inspectors so that they don't have to keep a mental list of what color is what path on every team's robot. It also helps when other teams provide assistance to you!

[CalTran]

It also makes it somewhat cheaper to buy wire, as a team would not have to buy a dozen different colors of different gauges.

[apalrd]

Originally Posted by CalTran

It also makes it somewhat cheaper to buy wire, as a team would not have to buy a dozen different colors of different gauges.

A team wouldn't have to. You could still buy a bunch of red and black if you wanted.

I also think this rule as written in 2012 doesn't make a ton of sense either, especially for sensor power wires. When wiring multiple sensors in the same location, I've often seen muli-conductor wire bundles used, which likely only have one red and black (if at all), while multiple sensor supplies and grounds are used (possibly independent analog/digital supplies, or something else).

[Jeff Pahl]

Originally Posted by apalrd

I also think this rule as written in 2012 doesn't make a ton of sense either, especially for sensor power wires. When wiring multiple sensors in the same location, I've often seen muli-conductor wire bundles used, which likely only have one red and black (if at all), while multiple sensor supplies and grounds are used (possibly independent analog/digital supplies, or something else).

A multi-conductor cable is typically going to include all the colors listed as being acceptable for supply and return colors (assuming a typical conductor count). There also will be a few other colors that can be used for sensor values.

As an inspector, I both love and hate this rule. I really like being able to go up to any robot at a competition and make at least some sense of the wiring. This is very important, as I often have my head inside robots that are not working. I absolutely hate having to tell teams that did not bother to read the rules that all the pretty wiring on their robot is not in compliance with said rules and needs to be fixed.

I understand the reason the rule is written the way that it is. Would love to have them add some more colors, like yellow and orange, etc. My team was frustrated last year by not being able to use multi-color ribbon cable for a run to multiple pneumatic solenoids on the end of the manipulator arm. But it did not meet the color requirement so they worked out another way to do it.

Could be worse, I worked on a project once where the specification was "All wire shall be green". It was a translation error, should have been "all ground wire shall be green" but no one wanted to fix it, so we had 50 pin connectors with all green wire on them. I don't recommend that

[apalrd]

I've seen harnesses where all of the wire except the main battery cable to the fuse panel is 18 or 22 gauge white, labeled at each end with paper and clear heat shrink. The harness had very few issues, especially for how it was treated.

I've always interpreted the rule such that any load-side connections between a relay or victor can be any color. We had a specific instance where we used multicolored 14 gauge automotive wire between the Victors and the motors mounted on our turret, to reduce weight over the 12 gauge red/black zip cord we usually use. The weight savings were significant enough for us to do it during the 6 hour unbag window between two competitions.

Maybe the rule should be re-written to exempt low voltage sensor wiring (6v or lower) and all switched circuits. As it is now, Jeff's situation would have been legal (IMO) by the letter of the rules if you had used a spike relay to control the pneumatics instead of the pneumatics bumper (as long as the ground was black or blue) which makes very little sense.

[Bob Steele]

Originally Posted by apalrd

Maybe the rule should be re-written to exempt low voltage sensor wiring (6v or lower) and all switched circuits. As it is now, Jeff's situation would have been legal (IMO) by the letter of the rules if you had used a spike relay to control the pneumatics instead of the pneumatics bumper (as long as the ground was black or blue) which makes very little sense.

The rule has exemptions already for :

outputs of relay modules, speed
controllers, or sensor outputs

The rule also pertains to constant polarity wires only.

The spike relay still needs to be wired (for power) and then it uses a PWM cable for control Using the pneumatics bumper eliminates the need to power the spike through the power distribution panel.

[apalrd]

Originally Posted by Bob Steele

The rule has exemptions already for :

outputs of relay modules, speed
controllers, or sensor outputs

The rule also pertains to constant polarity wires only.

The spike relay still needs to be wired (for power) and then it uses a PWM cable for control Using the pneumatics bumper eliminates the need to power the spike through the power distribution panel.

If you're only using one or two solenoids, it is likely weight negative to do all of that instead of using the pneumatics bumper and NI high side switching module (which is not light at all), since you must already wire the pneumatics bumper for power. However, even if you had more solenoids, you could still do that and use incorrectly-colored wire for the high sides to the pneumatic solenoids, which you cannot do when using the pneumatics bumper.

I think all sensor wires should be exempt, including sensor power and sensor grounds.

[Bob Steele]

I agree with you about sensor wires or wires carrying some arbitrary low amount of current whatever that might be. It would be so much easier to use ribbon cables for those control functions...

One of the issues is that many of us have 24 volt solenoids and they cannot be controlled via the spikes...It is harder to find 12 volt solenoids in commercial applications for some reason.... We always have two pneumatic shifters (controlled via one solenoid) so it is a tradeoff for us... but we usually use 2-3 more pneumatics along with the shifter...

[Tristan Lall]

I believe FIRST was responding to non-North-American teams which were having trouble finding wire that did not comply with IEC 60445 (which is described in rough terms here).

Incidentally, this thread has prompted me to go track that standard down for another project, so if I find a copy at the library, I'll verify whether FIRST's rule is consistent with it. (If I read that linked chart correctly, our systems are unearthed DC, not negative-earthed DC, so grey, not blue should be reserved for negative. But I'd rather double-check the definitions before making any conclusion.)

I wouldn't say this is at the top of my list of rules that need to be taken out back and shot,¹ but it has issues like no exemption for custom circuits (even COTS ones like fans), and odd consequences like when someone combines +12 V and +5 V to get a +7 V output with an unusual voltage reference (they're both red wires).

¹ Bumpers.

[Al Skierkiewicz]

Scott et al,
The color codes (and ampacity specs) are taken from the NEC (National Electrical Code) and the European equivalent of the NEC. In past years the rule had stated the color codes were for PD branch circuits so that sensor wiring was excluded.

[FrankJ]

The standards are some what conflicting.

IEC likes Blue for zero volts. The NEC likes blue for non zero DC volts. A good many panels in the US will use Blue for +DC & Gray or Blue with white stripe for 0V. The AC parts of the NEC call for white for neutral or grounded conductors & Black for non grounded AC conductors (Highly simplified). In DC Black for zero volts & Red for positive is pretty universal. Except Black & White twisted pair is really common for shielded control wires. Some plants like using black for the 0 V which makes white positive. Others use white for O V (It is the "neutral" color) which makes black positive (hot). The DC 0 V often gets grounded somewhere in the plant, making the black wire the grounded conductor. (A big NO if you are on the AC side of building wiring.) The take away here is unless you are somewhere that is really rigid about following one standard: you need pay attention to where the wire is going in addition to the color of the wire.

I would like to see the rule for wiring colors relaxed for multi conductor cable going to sensors & other low power items. The 2012 rule still requires the sensor supply wires conform to the color code. I can see still requiring the color code to be followed on single conductor wire.

[JDL]

There really is no good existing standard for FIRST to copy. The NEC, UL 508, NFPA 79 all are mostly AC centered. With the NEC we can basically use anything but gray, green and white for our ungrounded "hot" AC conductors.


For FIRST I'd like to see something like red for +12, blue for +24, and yellow (or similar) for +5, and black for all negative conductors. Conductors in cables should be allowed to be re identified if you want. If you want to identify negatives per voltage twisting, tyrapping, lacing, labeling, taping (either "phase" taping the negatives or using tape to bundle) would be optional.


No matter what the color code is though everyone should get into the habit of using a meter to confirm. One of the first thing you learn in the real world is once maintenance guys get at it and contractors guys start applying WIT (What's In the Truck) all bets on color are off.

[Jon Stratis]

The rule, as it stood last year, gives you plenty of options - 4 for the positive terminal, 2 for the negative terminal.

I certainly applaud your efforts to separate your wire colors for 12/24V... just do it within the confines of the rule There's nothing wrong with using red and black for 12V, and white and blue for 24V, for example. It's within the rules, and it gives you the separation you want. For my team, we haven't used pneumatics since our first year. As a result, we've standardized our wire colors around gauges, so it's obvious what gauge the wire is at a glance.

This rule hasn't changed for a very long time, and I doubt you'll see it change much in the future. As you pointed out, industry applications have their standards and codes, why shouldn't FIRST have its standards as well? As an inspector, I can tell you that having standardized wire colors makes things MUCH easier when helping out any team at the competition. It allows us to unplug things, swap components, etc without worrying about what that particular team's "standard" is - we follow the FIRST standard and everything works out fine.