Wiring Question

[elogicca]

Ok simple question i have 18awg magnetic wire, and would like to wire a transformer for 20 amps, 18awg is rated @2.3amps 8awg is rated for 24, 3 strands of 18 awg in parallel is roughly equivilent to the 8awg in dia.

So would 3x18awg = 7 amps or 20amps ??

Thanks

[Al_The_Man]

Where did you get the rating for 18g as 2.3a?
The current rating somewhat depends on what use it is put to, but I show it to be around 7~8 amps for most uses.
This would put it in the ball park for 20amps when x3 conductors, just make sure you wind them all together and not one winding after another.
Al.

[elogicca]

http://www.powerstream.com/Wire_Size.htm

For power transmission transformer winding...

[elogicca]

Oh wind them together, ok i was thinking seperate then linking the ends....

[wkkline]

The circular mil area for 18 gauge wire is 1620 mils.
Since the current carrying capacity of copper is considered
to be 700 mil per amp:

3 wires X 1620 mils = 4,860 mils
4,860 mils / 700 mil per amp = 6.943 amps

[Al_The_Man]

You will notice that they state the recomended sizing is very conservative, You will probabally never see a situation where your calculated current is going to exist for very long periods of time, these figures are mainly concerned with the resultant heat build up due to current.
What I mean by wind together, is not one winding on top of the other.
For close balance between windings, they should be all wound along side each other, and then the ends joined.
( notice that 18g is rated at 16amps for chassis wiring!)
The fact you are using 3 conductors, probabally affects the equation completely.
Al.

[elogicca]

So thats 1 for safe and 1 for magic smoke