Low voltage Network system cable?

froshtyv

Hi,

I have a quick question if anyone could help me out?

Basically there was cables ran for thermostats in house.

Some 2 core 0.75sq screened flex and a 1.5sq NYMJ were ran.

It was to be 230V stats originally but now has changed to a network system.

Ideally CAT5 FTP would be used for the stats but now that the cables are in thats not possible.

Has anyone any experience with using flex or 1.5sq cables for a network system?
Or what would the implications/ problems be?

Thanks

Have you enough cores in the flex? You should be ok otherwise.

2011

It is hard to know without more information.
How are the cables to be connected to the stats? Is it with RJ45 type plugs?
Post details of the stats and the network system and I may be able to answer.

mikehammer67

looks like they ran a flex for volt-free and nym for power

i'm not familiar with network stat but this one
http://www.heatmisershop.co.uk/downloads/1351683563copy_of_dtts_manual.pdf

has a pair for volt-free
pair for comms
and a pair for 12volt

so it may not work out going by that assuming the nym is 3-core?

mikehammer67

implications/ problems would be

-no of cores
-terminations? as said
-lack of screening/segregation on nym

hard to say without more info anyhow

froshtyv

Thanks for the reply,

Its for the heatmiser network system.

There is enough cores at each stat, they need 6 cores.

There 10 cores at each stat.

2No. 2 x 0.75sq screened flex & 2 x 3x 1.5sq solid cable either nymj or twin and earth

froshtyv

The Thermostats and Wiring Centre are linked below;

http://www.heatmisershop.co.uk/heatmiser-prt-n-12v-network-programmable-room-thermostat-p17

http://www.heatmisershop.co.uk/wiring-centres-c2/heatmiser-uh1-8-zone-wiring-centre-p58

mikehammer67

froshtyv wrote: »

Thanks for the reply,

Its for the heatmiser network system.

There is enough cores at each stat, they need 6 cores.

There 10 cores at each stat.

2No. 2 x 0.75sq screened flex & 2 x 3x 1.5sq solid cable either nymj or twin and earth

hmm

so are they 'daisy-chained' or 'home run' cables

you're ok if they're all 'home run' back to wiring centre

but i have an idea they may be daisy chained power and call loop-if you hadn't planned for network stats


that could be a bit of a problem

froshtyv

mikehammer67 wrote: »

hmm

so are they 'daisy-chained' or 'home run' cables

you're ok if they're all 'home run' back to wiring centre

but i have an idea they may be daisy chained power and call loop-if you hadn't planned for network stats


that could be a bit of a problem

I know what you mean they need to be individually brought back to the wiring centre for each stat to have its own "address" as such.

I have a feeling that they daisy chained the cables also, as they are in separate apartments so they ran the 2No. Flex's and 2No. NYMJ to each appartment rather that to each stat in each apartment.

I just wasnt sure if there would be a problem using a flex for the low voltage rather than the recommended CAT 5 FTP.
I know they are different than for a Ethernet port etc..

mikehammer67

my bad there -the call loops would normally be home run not daisy chained

same as with your proposed system

best check anyhow


not sure about flex for comms-someone here will know

froshtyv

mikehammer67 wrote: »

my bad there -the call loops would normally be home run not daisy chained

same as with your proposed system

best check anyhow


not sure about flex for comms-someone here will know

Cheers for your help.

mikehammer67

i would have thought its ok

there's no high speed transfer needed like

froshtyv

mikehammer67 wrote: »

i would have thought its ok

there's no high speed transfer needed like

I think the only problem might be in the NYMJ cable as its not screened.

mikehammer67

froshtyv wrote: »

I think the only problem might be in the NYMJ cable as its not screened.

the nym should be ok for 12v

but you'd need 2 home runs of the screened flex from each stat for comms and call loop

makes everything messy compared to a simple cat5

2011

froshtyv wrote: »

Hi,

I have a quick question if anyone could help me out?

Basically there was cables ran for thermostats in house.

Some 2 core 0.75sq screened flex and a 1.5sq NYMJ were ran.

I think that you would have great difficulty terminating these cables into the type of stats that you have purchased mainly due to the conductor size.

I was unable to find a data sheet for the thermostat or Wiring Centre. As the system is referred to as a "network" and that screened CAT5 cables are recommended my suspicion is that there is some sort of data transfer between the stats that goes beyond simple on/off control (I am open to correction on this). For this reason I would not think that a combination of other cable types will work reliably or at all.

As mikehammer pointed out each stat should be wired directly back to the Wiring Centre. A basic wiring schematic is shown here. I am not clear if you have this or not.

If this is a road that you still want to go down I see that the same company also offers a wireless option.

ted1

These guys have plenty if options with regard wireless stats. http://www.syxthsense.com/home.php

I've used them a few times and there good to deal with

mikehammer67

2011 wrote: »

I was unable to find a data sheet for the thermostat or Wiring Centre. As the system is referred to as a "network" and that screened CAT5 cables are recommended my suspicion is that there is some sort of data transfer between the stats that goes beyond simple on/off control (I am open to correction on this). For this reason I would not think that a combination of other cable types will work reliably or at all.

you may be right-i'd like to get the definitive answer to that question

with nyms and separate flexes it would be a bit of a bodge anyhow at this stage

it maybe best consider alternative options