What's the max voltage and amps that can be sent down the following?

6 core Alarm cable....(does it affect the max voltage and amps If doubling up and is it correct if you double up? Or is it a no no?)

0.75mm flex...

1.0mm twin and earth....

1.5mm twin and earth....

2.5mm twin and earth....

Max voltage is on the cable. I think alarm cable is 50v

Mains cables are usually rated for 1000v

Max current depends on volt drop and installation method.

Without consulting the big red book Off the top of my head,

1mm around 10 amps

1.5mm around 16 amps

2.5mm around 26 amps

All dependent on clipping method/materials etc.

Surely those currents are at 240v?

Doesnt matter what voltage. But the higher the voltage the less the voltage drop.

http://en.wikipedia.org/wiki/Electrical_resistivity_and_conductivity

Correct Fozzies,unless your connecting your t+e directly to a 10 kv substation that's the assumed voltage.

That's why the distribution network is HV, as James I squared R losses.

Without consulting the big red book Off the top of my head,

1mm around 10 amps

1.5mm around 16 amps

2.5mm around 26 amps

All dependent on clipping method/materials etc.

That's the important bit. Cable in plaster and cable in open air have two different values.

Also the question didn't state AC or DC.

I thought Twin and Earth was rated to 600V?

Rated voltages are normally in RMS values.

As for alarm cable is it a signal cable.

Rated at 1 amp per core and 50v RMS.

It is recommended to double/triple up on cores for power to reduce voltage drop.

If you can't double up both pairs, double up the negative first when using DC.

In an alarm system I wouldn't be expecting to get near the max values due to the battery capacity and rating of the PSU.

Resistance and Voltage-drop are the problem here.

affaik stranded alarm cable is/was rated at 1amp @ 50 volts per core, double up to handle 2 amps but don't exceed 50 volts.

Doesnt matter what voltage. But the higher the voltage the less the voltage drop.

http://en.wikipedia.org/wiki/Electrical_resistivity_and_conductivity

can i qualify - as long as the voltage don't exceed the makers recommended voltage, so don't stuff 240 ac down alarm or network cable as example.

as it happens, i tried to get the voltage and current rating for CAT5e, can't seem to find it. question came up about POE cameras, so i think 48 volts DC @ 1amp.

on an american electricians forum (bless Google) one guy stated 2.5 amps no problem

Arf the wattage of Poe is a relevant point. How have you found it? I don't see the 48w an issue but i do look forward to v4