Wires thickness

[Vertigo]

Hi chaps,
Just a quickie.
What thickness of wire would you recommend for safely carrying 9 volts from a power supply to the circuitry I actually want to power? Very small wire used for controller mods or console switching would probably be too flimsy for the purpose, so I wonder if someone can recommend the right sizing for safety.
Thanks.

[kendrick]

Voltage is less important than amperage, but if you're carrying 9 volts over a distance of less than ten inches then 22 or 24 gauge wire should be sufficient. I always overengineer power connections when I'm doing them, and I'll have 18 gauge wire in there for no reason other than that I have it lying around. But as long as it's DC and under 1.5 amps, then 24 gauge should be plenty safe. If you're really worried about power usage and possible heat issues, then you should also drop a fuse in there just to be safe.

-KKC

[Vertigo]

Measurements are as follows: 9 volts, under 30 watts, under 2 amps and yes, direct current.
I'll be fusing it anyway for safety even though I'm in the UK so all our wall plugs contain fuses.
Thanks for the advice.

[Aidan]

What circuit are you powering?

As far as fuses in wall plugs go, they're designed to protect the cable against short circuits, rather than protecting the appliance. Most wall plug fuses actually need a current nearly twice their rating to ensure they rupture.

Wattage is calculated by multiplying voltage by current. Hence, 9V at 2A is 18W.  

[atom]

On a further note your fuse will be useless if you're wiring isnt strong enough. If you use 4 gauge wiring and a 15 amp fuse, your wiring will act as the fuse and will *pop* way before your fuse ever would. It will overheat, the plastic will melt off the wires, the carpet will catch on fire... and so forth. I would reccomend 20 guage wiring even though I dont know what amperage your using. I imagine it would be safe enough.  

[Vertigo]

Amperage is about 1.3, I'm using a Megadrive power supply for this project and it's fused internally so fusing shouldn't be a problem.
And yeh, I know about the wires overheating and dying, burning my fingers many times on stupid science experiments with batteries at school taught me that long ago, which is why I was curious about wire thickness, but I have the info I need for now, so thanks for your answers guys, I'll try to work out the rest of myself.