Favorite tools, materials, and techniques for FRC wiring

#1

Favorite tools, materials, and techniques for FRC wiring

Wiring up an FRC robot is much more an art than a science. Yes, it’s entirely possible to win matches with electronics that look like a rat’s nest…

…but don’t come crying when you have to track down a faulty connector. If you want to build an electrical system that’s both reliable and aesthetically pleasing, you’ll need to up your game with the right tools, materials, and techniques .

Essential tools

Before we dive into materials or techniques, let’s talk about some essential tools that I’d recommend to every team. I’ve included links to purchase each item.

Greenlee 10–24 AWG Wire Strippers

You can’t go wrong with these. They cover every gauge of wire you’ll use in FRC (except 4AWG, which gets special treatment). Their ergonomic design makes them extremely easy to use. If you’re considering automatic wire strippers, I’d strongly advise you to reconsider these strippers. I think it’s much easier for a novice to pick up a pair and get to work making clean, accurate cuts, while automatic strippers can be rather finicky to use. Note that the product page for these guys says 10–22 AWG, but that’s a typo and they’re actually 10–24 AWG (just look at the image). Get two or three of them.

Hakko Flush Cutters

AKA flesh cutters , this tool is used for making, you guessed it, flush cuts. These are dirt cheap and work great. You’ll be using them primarily to cut zip ties; you should NEVER use them to cut wire larger than 18 AWG (see the MAX CUT 1.3mm label!). Use the base of your wire strippers to cut wire instead. You’re going to have a lot of zip ties to cut in your future, so get three or four of these.

Powerwerx TRIcrimp

This is what you’ll be using to put connectors on the ends of wires. Don’t worry too much about that right now. Just get one of these.

The right materials

Now that you have a good set of essential tools, let’s get the right materials.

Red/Black Zipcord

This stuff is your bread and butter. If you’ve worked with speaker wire before, this is pretty similar, you just want to make sure to get it in red/black insulation. Having your conductors bonded together makes laying out and tracing wire ridiculously easy. Unfortunately, I haven’t (yet) found a good source of this stuff online. Some online vendors sell it with a “glossy” insulation that doesn’t separate cleanly and can really gum up your cuts, so watch out for that. The photo is actually one I took at a local electronics store a few days ago, and I recommend calling up local shops to check if they carry this type of zipcord — you can check in person to make sure it has a matte, non-glossy finish. Get a spool of 10 AWG (or 12 AWG if you can’t find 10 AWG) and a spool of 18 AWG. These will be pricey, but last you multiple seasons.

PP45 Anderson Powerpole Connectors

These are the connectors you’ll be attaching to wires using the TRIcrimp. Again, don’t worry too much about how they work right now. Get 100.

4.75"x1/8" Zipties (get two or three packs)

14"x3/16" Zipties (one pack is fine)

These are just zip ties. You’ll want a lot of narrow ones for detailed work and a few wider ones for big bundles. There’s nothing special about the ones I linked, feel free to choose any zip ties as long as you have a few wide ones and a bunch of narrow ones.

Reliable techniques

Tie it down

Tie down your wires! I don’t care how far away they are from gearboxes, chain, etc., if you don’t tie them down they’ll find a way to be somewhere they aren’t supposed to be. Tying down your wires will also make them easier to visually trace.

Try to space your zipties consistently. Prefer 90 degree bends with consistent radii to “curvy” routing. If you don’t have a diamond bellypan like the one depicted above, get a sheet of polycarb, ABS, or plywood. Drill a pair of holes around the wire you want to tie down, and run the ziptie through the hole.

Trim your ties

Once you’ve tied down your wires, it’s time to trim the excess from your zipties. This is what the flush cutters are for. Make sure to make clean, flush cuts as incomplete cuts can leave sharp edges that can draw blood when you’re sticking your hands down in the electronics.

Use Powerpoles

It’s time to use the TRIcrimp and PP45 kits you bought earlier. This is honestly pretty easy to get right, and the above video will give you a good idea of how to do it. Just make sure to use the “45” slot on the crimper as you’re using PP45 kits with 10 AWG wire.

You can stack these connectors in any configuration you want. If your robot uses an elevator, consider connectorizing all power wires that go to the elevator, and stacking the connectors together on each side. If you ever need to take the elevator off the robot for maintenance, you’ll be able to disconnect those power wires from the base in one quick motion.

Leave room for servicing

This one is really easy. Don’t lay your wire out so short that you can’t (un)plug it into your components. Leave a little bit of extra room.

Things I’m meh on

Labels

I’m not a big fan of labels. Usually if you need a label, it means the wiring isn’t easy enough to visually trace. That’s what we’re trying to avoid in the first place.

Ferrules

I’m pretty meh on ferrules. All of the components you’ll work with in FRC don’t require them, and aren’t particularly hard to use without them. If you want to use ferrules, go for it, but I don’t know if it’s worth the extra time.

Conclusion

This post really only scratches the surface of FRC wiring. I’m considering writing in greater detail about the following topics, in no particular order:

  • Making your own CAN/PWM wires
  • Wiring great looking batteries
  • Designing {metal, plastic, wood} bellypans

What would you like to hear about? Was this post useful? Anything you disagree with? Please let me know!

51 Likes
How to mount the electronics effectively to save space and clean and tidy?
#2

Great post! I’d be interested in hearing about crimping and making our own 6 awg wire and SB50 connecters.

#3

I’d like to cover that as part of the batteries tutorial, but I’d use 4 AWG. Unfortunately I’m not sure how I’ll do that without a physical battery to take pictures of, so it might be a while.

#4

A link to the tools that you recommend/use would be helpful. Where to find the lugs and crimp tools for 4 awg wire would be really useful.

1 Like
#5

I think I’ve ordered the lugs from McMaster before, I forget what size screws the batteries use though. I’ve also found them in passing at electronics hardware shops.

A swaging tool works rather well for crimping them.

#6

Hima:

Grab the Harbor Freight hydraulic crimp tool. There are nicer crimpers that work better, but these work fine and are cheap. Make sure you section your first two crimps to check your crimp quality, getting the release valve fully seated/sealed can be tricky the first couple times. The tool does leave a little bit of flashing on the anderson contacts that you’ll want to file off to fit into the connector.

If you use #4AWG welder wire with >370 strands, you’ll want to swage the #6 anderson contacts per Triple Helix’s paper. The improvement I would make is you can cut your own swage by beheading a 1/4-20 bolt instead of trying to lathe something down precisely.
If you find #4Awg with 370 strands, you can probably fit in the contacts without swaging.

You can get lugs on Amazon that work fine, the #10 bolt size coupled with #4AWG compatibility and a 90* bend is rare and expensive. We bend these ourselves to get the leads onto ziptie holders, Team 33 style. We haven’t found a cheaper option than the Panduit MCMS12P-C ziptie holders Jim Zondag specs.

There is an active discussion in the community on whether to use an internal+external star washer or the NordLock washer system or both. Functionally, as long as you have a nylon nut, you’ll be fine.

@connor - no love for 30A or 15A Anderson contacts? You’ll want 15A contacts for the 18AWG zipcord…

2 Likes
#7

We us SB120s and 2awg wire.

Also strongly suggest the following:

https://www.newark.com/weidmuller/9028680000/kit-crimp-tool-wire-end-ferrule/dp/65T5309

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#8

Bonded zip cord various size.

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#9

If you are taking the time to fabricate your own harness from the battery to the PDP, I recommend that you locate the gauge of welding cable you intend to use - regardless of 6 /4 / 2 gauge fans the welding cable significantly improves the flexibility of the large cables. Suggest you look at ebay or amazon - two of the easier sources. As for the compression lugs, I usually look for a lot of lugs on ebay - tough to compete with those prices!

#10

Do you know if this has the glossy finish, or is it matte?

#11

A few years ago we got this wrap around sleeving in the KOP, however I forget the exact brand of it. It was similar to this from McMaster however I haven’t ordered it to see. Does anyone remember what I’m talking about and the brand of it?

#12

Speaking of batteries and 4 AWG, I’d really recommend KnuKonceptz OFC.

Here’s a photo of some batteries I’ve worked on:


I usually don’t bend the lugs and try to keep the battery-side wire consistently short (about 1 foot).

#13

Connectorizing the 18 AWG is left as an exercise for the reader :smile:

2 Likes
#14

This thread is a great read, especially the picture of the batteries that say “do not lift by wires!”

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#15

How to you make this work on the PDP side?

#16

Powerworx bonded wire is great, but it’s way heavy.

We also tried some of that supple silicone wire from CTRE, but found it was like working with a wet noodle and used the Powerworx stuff instead.

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#17

We grind the lug to fit.

#18

Please please please put non-conducting putty on those!!! Either that or a non-conducting collar. That should be a part of any electrical battery tutorial.

1 Like
#19

IMO thick heat-shrink provides the most aesthetically pleasing result. I think we ended up just using electrical tape as a temporary fix though.

2 Likes
#20

Agree with shrink wrap being a cleaner look for sure.