Pneumatic compressor and switch awg?

Does anyone know what the awg value of the cables on the compressor and on the pressure switch? If so, please tell me as I’m in need of it so much!

Which compressor are you using? My team just uses CAN wire for the pressure switch (no real reason other than they are pre-wrapped, you could use similarly sized ~18 gauge wire), but the value for the compressor might depend on which one you want to use.

It’s a VIAIR 90C compressor

IIRC the Viair compressor has AWG 18 wires, but I could be off a bit. Unless I’m misunderstanding, the pressure switch doesn’t have wires, just contacts that you attach wires to.

Is there a reason you need to know the exact size of the wires?

Not a specific reason, I just don’t want to mess this up. Thanks by the way!

I was actually planning to combine the wires. so what’s the minimum awg for the cables that I can use on the compressor? Also the same thing goes for the pressure switch.

On the wiring guide for the VAIR (found here:, the minimum gauge you can use is rated at 16 AWG, for short distance, low amp uses. You may want to use 14 or 12 if you want to be safe, but 16 is the absolute minimum.

You can run #18 on the compressor and the switch wiring. That gauge will be easy to insert in the PCM. #16 is a little tricky. The switch cannot handle a lot of current but the #18 is easy to crimp and work with. when using a 20 amp breaker or fuse, #18 or larger is required.

^^ What Al said. See R60 for details.

The pressure switch carries signal level current, so as I read the rule you may legally use wire down to #28, but #18-#22 is much more convenient for the connectors on the PCM and the screw terminals on the pressure switch. OBTW, I definitely recommend using [red] automotive crimp-on ring connectors for the pressure switch, not just wrapping the wire around the screw and tightening!

The manual for the PCM states that the maximum wire size is #16. We found that the larger wires like #16 must be straight with all strands slightly twisted together. It then must be inserted while oriented exactly vertically with a vertical motion. If it is not vertical when inserted, some of the strands will catch on features inside the connector resulting in a small “birds nest” as the wire is pushed in further.

The datasheets for the Weidmuller connectors actually shows #14 as the maximum wire size but I don’t know how that will really work in real life.

The strip length is specified as 3/8" in the PCM manual. We found that a shorter strip length may not give enough conductor for the connector to hold securely. A longer strip length results in exposed conductors after the wire is fully inserted.

Last year, working as an RI, I found instances of wire-to-wire shorts in three different robots because of a combination of the issues described above. The easiest way to inspect these connections is to use a bright light shining from different angles on the area where the wires go into the connectors. There should not be anything shiny (bare metal) in that area.

#14 solid wire might be inserted, but #16 stranded is the max wire size. However, robot rules allow #18 for 20 amp breakers and that is what I recommend.