Question regards CAT5 cabling for CBUS Network

Question - I'm running 2 "zones" of cabling - one for upstairs and one for downstairs. Each take a different route down to the CBUS DIN rail units.

Now, instead of running 11 cables from upstairs, and 10 from downstairs, would there be any problems in me joing up the connections for upstairs before continuing as a single cable ?

So , I could take all 11 cat5 cables from upstairs to a junction box, and from there a single cat5 goes on to another junction box next to the din rails (where it now joins the downstairs cabling). From here, one cat5 goes into the first CBUS DIN rail unit.

Make sense ?

G.

 

Gareth

They're having a holiday today in Aus

You can wire any way you like as long as you dont cause any loops.


Dean.

 

Spur

Thanks - wasnt sure if a "spur" would reduce the integrity of the cbus data signal if it was being split like this.

Saves on the pink stuff

Oh, and what a b'stard it is to change UK backboxes to a JBox in a solid wall !

G.

 

I cheated in my own place with the J Boxes.

As they are LV, and not on flammable surface, i.e. breeze block, I bought the plastic j Boxes and cut off about 15mm at the front only - removed the tabs and cemented in place - Much easier



Dean.

 

Hmm, not looked at the DIN units but I am curious why you would want to run a C-BUS cable from each input unit to the DIN unit, that is what you were getting at wasn't it? I cannot see why you wouldn't just run one cable from downstairs to upstairs and then star or daisy chain off the other units rather than at a junction box. You wouldn't even need a junction box as another poster suggested. Also the best way to do downstairs too. The only issues would be to ensure you don't create a loop, and I also thing if you have multiple power supplies that the C-BUS people recomend that they be spread over the network rather than concentrated.

The only thing that will require indicidual cables would be the loads themselves.

 

Topology

Ashely

Not quite, no. I have 16 Switches to connect to 3 DIN units. 11 switches upstairs.

So, I would bring all the cat5 to a junction box, and take a single feed into the first DIN unit (and then join to the next din, then the next dim, etc)

I'm not taking 16 connections into the first DIN directly.

My question was regards upstairs where I can save on cable runs - could I join all 11 up in the loft, and then bring one cable down to the junction box where all the downstairs cables join.

G.

 

cabling questions for cat 5

gday,
theres nothing wrong with jboxes on network cabling but its definitly not good installation pratice.why dont you loop in and out of your switches upstairs and just take one back to the din unit.pink cat 5 is cheap compared to the time it will take you to find a network fault it you have problems .which you will increase the chance of by having 12 cat5 cable some how properly terminated.loop in loop out if you think about it wouldnt use that much more cable by the time you run the longest switches back to your jbox.

 

There's nothing wrong with what you aim to do, as previous respondents have commented wire it any way you like as long as the TOTAL cable length doesn't exceed 1km and that you take due regard for volt drop over long runs (see volt drop calculator on CIS web site http://www.clipsal.com/cis/pdf_files/CBus-Voltage-Calculation.pdf ) in any event you are much better off having all your various Cat 5 cable consolidated in a patch panel or punch down block or other termination block and then take just a single length into the switch board.

 

Length

I've got a full box of pink cat5e, so that's enough I think for me (300m)

Thanks all.

G.

 

Daisy chain the way to go

Assuming that both upstairs and downstairs are on the same network by far the simplest method that I can see it to daisy chain the units together. i.e. unit 1 - unit 2, unit 2 - unit 3, unit 3 - unit 4, etc. etc. etc. If along the way it is more convenient to use a star configuration this is also okay but as mentioned before avoid creating a loop.

Regards,

Peter Brown.

 

I always run my c-bus cables in the form of a ring, but only connect one end at the dimmers etc. The other end of the ring isn't connected. The reason for this, is if the cable has a fault on it at one point at 2nd fix stage. i can then connect the other end of the ring to form to raidal ciruits.