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I am presently using a 4 wire bus for CAN (CANH,CANL,PWR,GND). This is used all across the design for various boards. Now the cable needs to be shielded.

Would this imply using 5 pin connectors and crimping the shield into one of them (which is then connected to ground) Or is there a different way to this?

How is the drain cable connected to housing or ground when you're making a million units?

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    \$\begingroup\$ Now the cable needs to be shielded Why? because, honestly, if there's enough noise to disturb a 120Ω-terminated differential current signalling bus, then your devices will be just as susceptible to noise. There might be good reasons to add shielding, but I hope you have them – otherwise, the shield won't do much good. \$\endgroup\$ Jun 23 at 12:48
  • \$\begingroup\$ (the cabling for the CAN analyzer devices I've seen are unshielded, for example, because a shield can lead to more trouble than it's worth.) \$\endgroup\$ Jun 23 at 12:55
  • \$\begingroup\$ These are very valid concerns. Why does it need to be shielded? Shouldn't you address the cause rather than the symptoms? Especially if making a million units... shielded cables are very expensive. \$\endgroup\$
    – Lundin
    Jun 23 at 13:26
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If a designer is worried about radiating cables then shielding is a good idea, in most designs the shield pin would be tied to chassis ground. The scheme extends the chassis and prevents EMI from interfering from the inner conductors and prevents radiation from the conductors from reaching the outside world. In either case the return currents from the radiation flow down the cable through the shield to the board, The most designs it's best to direct these currents to chassis ground and away from the PCB to prevent common mode noise.

As a designer you need to decide if radiation would be a problem which would typically result from other switching loads on your design. Just the canned bus will probably not be enough of a potential radiator to justify shielding, there should be another reason.

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Would this imply using 5 pin connectors

Yes, the CAN standard comes with 5 signals, where CAN shield and V+ are optional.

and crimping the shield into one

What connector is that? Crimping a shield sounds strange. Normally you either trap the shield against chassis in one end, or you connect it to a signal which is grounded in one end. There's pre-made cable assemblies like these where the shield is connected to a pin 1 (as specified by the CANopen standard). Shielded cables is an expensive solution however.

How is the drain cable connected to housing or ground when you're making a million units?

A million what? It's connected as makes sense for the very specific application.

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I have already created CAN networks communicating at 500 Mbps using 60 meters of 4-way PP cables. Of course this is not ideal, but depending on your application it will work.

The other answers are correct. In fact, the return current must be directed to the chassis. If possible, use twisted-pair cable as the standard CAN suggests.

In fact, shielded cables are expensive. Check if you really need it.

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