i'm making extensions for my power supply, what voltage and what ampage does the wire need to take?

for the power cord to the wall or for wires inside the 'puter?

from the wall... 120v and 15a would be fine... I think 14 or 16 gauge is normal...

inside the computer... 12v and say...probably in the 40 to 50 amp side to be safe...
I use 18 or 20 gauge for my wiring

its for inside. 60 amps is a bit high isn't it? i would have thought it would be about 12 - 20.

depends on the PSU....but remember that it is 12v or less......so higher amps is OK...

60amps at 120v would require a great big ol' wire....but at only 12v it is ok....

but it varies from the voltage...

a 5v or 3.3v rail could see higher amps, the 12v line will probably only see 20 or 25 max


its all about Ohms Law
http://www.the12volt.com/ohm/page2.asp

Hope that makes sense

ok, just found my psu manual. needs at least 40A wire for the 5v rail. means i want 45 to be happy. where can i get that in the uk? maplin only go up to 32A.

If it is for wiring fans and such.... I just use 20gauge wire from the hardware store.....

its for fans, hdds, floppy drive, anything that comes out of the psu that isn't the mobo really. i'll see if i can find a hardware store.

that's 32A @ 500V... just goto maplin and ask for the same wire as molex leads... i'm pretty sure it's the 24/0.2 stuff you want (24 strands of 0.2mm copper) which should be £1.39 for 10M

- maplin man

Remember current requirements go up as you decrease in voltage to maintain the same power level. I'd think you'll be fine with any load you'll be running if you use 18 gauge, even though that might be overkill.