# Debug document for CAN bus wiring

**URL:** <https://klipper.discourse.group/t/debug-document-for-can-bus-wiring/9156>\
**Category:** General Discussion\
**Created:** [June 26, 2023, 4:50pm UTC](https://klipper.discourse.group/t/debug-document-for-can-bus-wiring/9156 "2023-06-26T16:50:16Z")\
**Posts on this page:** 1\
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**Author:** ![mykepredko](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/mykepredko/32/2085_2.png) [@mykepredko](https://klipper.discourse.group/u/mykepredko)\
**Post date:** [June 26, 2023, 8:57pm UTC](https://klipper.discourse.group/t/debug-document-for-can-bus-wiring/9156/2 "2023-06-26T20:57:17Z")

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It looks really good - the only comment I would make is on what wires users should use for the CAN bus.

Users should use 28 AWG stranded twisted pair wires with an approximately 120 Ohm characteristic impedance like:

> **[3302](https://www.alphawire.com/products/cable/alpha-essentials/communication-and-control-cable/3302/)**
>
> Alpha Wire's 28 AWG 2 Conductor communication cables provide precise signal transmission in computers and control applications

For wires that’s all in one (ie single 28 AWG twisted pair for the CAN bus and 2x 22 AWG wires for 24V power) for tool head PCBs, like the BTT EBB36/42 or Mellow FLY SHT36/42 I use the Tensility cable:

> **[30-02482.pdf](https://tensility.s3.amazonaws.com/uploads/pdffiles/30-02482.pdf)**
>
> 236.86 KB

As a final note, twisted pair cables should be purchased by the foot (or cm) - 100’ (30m) spools of these cables can cost $500 or more.

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