12v / 400ma - what gauge wire?

[LesCir]

I have a circuit of relays and diodes. Total draw will be 400ma at 12 volts. (Actual PS delivery is 13.2 volts).

What gauge wire do I need to safely hook this up? 

[Hero999]

It depends on many factors: the ambient temperature, maximum temperate rating of the cable insulation, the resistance of the conductor and the ability of the cable to dissipate heat, which depends on whether it's is buried, sheathed, in free air, coiled up and the how good a thermal insulator the electrical insulation is.

Here's a table giving general values.
http://wiki.xtronics.com/index.php/Wire-Gauge_Ampacity

Use the Wikipedia table, if you need to convert to metric.
http://en.wikipedia.org/wiki/American_wire_gauge#Table_of_AWG_wire_sizes

For 400mA I wouldn't worry about it, if it's thinner than #30, it probably won't be mechanically strong enough for what you need.

[LesCir]

Thanks... you're right, even with my enclosed wiring, it looks like anything in my parts box will do it :-)