C-Bus signal Cat5e wire, Is it really needed?

I have a dilemma.
I have a 60M panel with 5 dimmers and I have a 3/4" conduit to my low voltage electric box where all my C-bus terminate to other switches.
The switches have only the Cat5 wiring and within code.
I want to put 110VAC in the same conduit to power my Clipsal 350ma power supply I want to mount.
The USA code for NEC (National Electric Code) will not allow a low voltage wiring under 30vdc and not rated 600v to be in the same conduit as high voltage wiring cannot be with a low voltage wiring without a barrier (Isolation). But the city inspector does not know the term "barrier" and what is needed so they fail / red tag.

So my question is, can I just use 2 wires larger 20 gauge 600v rated to communicate for the C-bus and not use the Cat 5 twisted pair for communication.
Not on all areas but just in a 8 meter section.

I know there was a thread about using 2 stings with salt water for the C-bus which was hilarious.
But it means that the simplicity of C-bus just needs basic wiring and for the because of the wide availability of Cat 5 in the market it seems to be the perfect choice.


I am not using any remote wires so technically I only need 2 wires to communicate.


Thanks
Alan Dobbs

 

Providing that at least the same cross-sectional area of conductor is provided in the 8 metre run as C-Bus normally uses so that the run does not represent a potential fuse, it should be technically possible for your proposed solution to work. The close proximity to 110Vac wiring is a concern, so make sure the 8 metre run of cable for C-Bus is twisted.. I would say 6 twists per foot would probably be sufficient. Don't use flat cable. I am aware of many C-Bus installations using the pink C-Bus cable where the C-Bus cable is bundled together with double-insulated mains wiring for runs of over 50 metres. Not recommended, but it has worked well for many years.

I would prefer to see the same C-bus cable in this conduit as you use elsewhere, so that some years off in the future, it is still easy to recognise, but to either run the C-Bus cable or run the 110Vac cable within 8 metres of a smaller diameter conduit that is up to the task. The smaller diameter conduit can provide the barrier to isolate the C-Bus wiring from the 110Vac wiring, and the C-Bus cable will still have the right impedance and twist.

 

I will check with Square D and see if they stock as a 1000 foot roll then start pulling thru.

Here in the USA I searched many suppliers for Pink cat 5 to no avail. I even looked for pink shrink tubing to sleeve the ends but no luck.

As for the rating there is a difference as UL is 600V in the USA and for the same product I see the CE rating is 1000V.



Alan Dobbs

 

It is not just a matter of buying any old pink CAT5 or putting pink heatshrink on another cable. You need the special Clipsal cable which has this higher barrier rating. Does the US supplier of C-bus not stock this cable?