Can Alarm Cable be used instead of Telephone Cable?

[custard2000]

My first ever question for a forum- be gentle with me.
I have inherited a half finished project- where there are a number of telephone points in the house. Unfortunately it appears that the previous owner wired the telephone system in 8 core alarm cable rather than normal 3 pair telephone cable. Does anyone know if i can still use this for the telephone system or is this going to have to be ripped out and re-run? (i'd rather not do this as the walls have been plastered and painted).

 

[plugwash]

alarm cable is not ideal for phones but its probablly not any worse than the crap the diy sheds sell as phone cable.

also alarm cable is stranded so it won't punch down well, mostly you can get arround this by buying accessories with screw terminals but this may be an issue when it comes to joining to the customers side of a NTE5 master socket.

 

[Chri5]

In 1990 when I was working as a cabling supervisor with a staff of 20+ blokes on 5000+ voice point sites I decided to wire the voice for the whole house.

Used 2 x 100m drums then discovered that 1 x drum was stranded alarm cable not CW1308 x 4pr voice.

Felt stooooooopid, was stoooooooopid.

It's still in service today. The only real issue was that the alarm cable (as already mentioned) was stranded, so is non voice colour code and you do need to push the krone / IDC tool a few times to cut all the strands. It helps if you twist them well first.

If you haven't run the cables already, spend £15 and buy the CW1308 voice cable.

IDC terminations inside LJU's require 0.4-0.6mm cable core to make the correct connection.
Stranded splays out and although it will work, it could lead to sloppy / loose connections- Again, as mentioned screw terminal type LJU's are the best way forward in alarm cable is used.

 

[TicklyT]

It will probably be OK for a telephone, but it may give odd problems with broadband.

I would be inclined to give it a try.

If you have a problem with the stranded wire in the IDC connections, you could try choc blocing solid tails on the three wires you need in the back of the sockets.

If BB problems do manifest, you could try a single filter fitted at the NTE5, and run your extension wiring from the telephone side of the filter.

 

[plugwash]

If BB problems do manifest, you could try a single filter fitted at the NTE5, and run your extension wiring from the telephone side of the filter.

With the newer higher speed versions of DSL coming out for new installations i'd reccomend using a single filter at the master socket and then if the modem/router is not at the master socket doing the DSL side wiring in either BT spec cable or cat5 as a single non branching run.

for existing installations i might try a soloution that didn't involve messing with the wiring before going to the above.

 

[breezer]

alarm cable is no problem what so ever.

as forusing a krone tool , dont worry about it, since a krone tool is designed to push the cable into the connection while its insulated and then trims off the surplus.

 

[bernardgreen]

alarm cable is no problem what so ever.

as forusing a krone tool , dont worry about it, since a krone tool is designed to push the cable into the connection while its insulated and then trims off the surplus.

Stranded conductors do NOT make reliable connection in IDC ( Insulation Displacement Connectors ) used in telephone systems. The strands move to become a flat layer that is thinner than the gap between the contact face and the connection eventually fails. The main cause of delayed failure is corrosion / oxidisation of the wire creating an insulating surface between conductor and contact. In an IDC connector the edge of connector jaw bites into the conductor to form a gas tight joint. No oxidisation can occur in the bite area.

 

[breezer]

thats what BT will have you believe.

Although i do not disagree with your point on corrosion / oxidation, i submit the difference is negligable, so long as its twisted then kroned

 

[Stivino]

I've had four phone sockets running on alarm cable in my house for 17 years with no problems whatsoever.

 

[breezer]

I've had four phone sockets running on alarm cable in my house for 17 years with no problems whatsoever.

 

[plugwash]

i guess if you were really paranoid you could tin it with solder after twisting and before punching it down so its a nice solid mass.

 

[Chri5]

i guess if you were really paranoid you could tin it with solder after twisting and before punching it down so its a nice solid mass.

Fine if you can solder to within the 0.4-0.6mm IDC tolerance, over sized and that's the IDC fudged up

Go and buy some screw type LJU's

 

[Steve]

this is in the wrong forum now, surely?

 

[plugwash]

Go and buy some screw type LJU's

Fine for simple sockets but how do you get arround connecting to the NTE5 plate? I've never seen NTE5 plates or NTE5 filter plates with screw terminals.

i guess the best soloution is to solder/heatshrink on short tails of phone sized solid core wire but that seems like a lot of work.

 

[custard2000]

Thanks to everyone who replied. Some great information here, settled my mind (and wallet).