tel cable, cw1308- how many pairs??

[CharlieB1981]

hi,

was recommended on another thread to use cw1308 cable for telephone, yet searching for this shows massive differences from about 4 pairs to 10 pairs+earth,

this is only for a 3 bed semi and i want to future proof it as much as possible but any recommendations on how many pairs i'd need as 10 sounds overkill

thanks

 

[plugwash]

Normal domestic phone wiring uses one pair for the phone line and one wire from another pair for the ringer signal* which is generated by the capacitor in the master socket.

Most domestic phone wiring is done with two pair or three pair cable. Using three pair gives you a spare pair in case of failure, in case you want to wire your broadband with a single filter and then seperate filtered and unfiltered wiring (which usually gives the fastest and most reliable results) or in case you want to run a second phone line (though ideally you'd want four pair for that because running ringer wires for two seperate lines down the same pair is not ideal).

Higher pair count cables are usually used when running many lines down the same cable. Not something you'd normally do in a domestic situation.

You can also use CAT5 for phone wiring, this has the advantage that the tighter twists give it more resistance to interference. I've seen some claims of an impedance mismatch which could potentially affect broadband speeds when using CAT5 but I haven't seen anyone come up with evidence that this is significant and i've noticed that BT openreach themselves used CAT5** when doing my FTTC install. CAT5 cable is nearly always 4 pair.

* Note that in an install with broadband that the ringer signal is only needed in wiring after the filter(s) and is actually undesirable in wiring before the filters.
** Interestingly it was 2 pair cat5 which is an unsual cable type.