I'm helping a friend wire up an upgraded electric fan (Flex-a-lite BlackMagic 165, it's a nice one) and we may try to run it off the factory electric fan wiring so the ECU can switch it on. I haven't looked at the factory harness wires yet, but what is the smallest size of wire it could be for me to use it to carry a 14 amp load? The factory fan has constant ground and switched +12V. I can always use the factory wires to trigger a relay, but I want this to be as simple as possible.

This chart: http://wiki.xtronics.com/index.php/Wire-Gauge_Ampacity

says an 18 gauge wire can do 16 amps in free air and 10 amps enclosed. Under the hood of a car would be considered enclosed correct? So according to that chart it would need to be at least 14 gauge?

3/1/2009 10:27:37 AM

14 gauge will handle up to 15 amps, 12 up to 20

[Edited on March 1, 2009 at 1:46 PM. Reason : 16 wont handle much more than 10 amps]

3/1/2009 1:46:07 PM

Is 14amps the peak amperage or just opperating amperage? I found the specs and they only say 14A so I would assume that normal opperating amps. I only ask because the peak can be greater than 50% higher which would burn up that 14awg wire.

3/3/2009 7:34:14 AM

you need to use the factory wire to trigger a relay and run the fan directly off the battery. that's the correct way to do it.

3/3/2009 10:36:58 AM

you need a larger size wire if you're running this beside the radiator or through the engine bay. The additional heat will kill the thermal rating of the wire.

3/3/2009 11:47:50 AM

^^2nd'd

3/3/2009 12:39:12 PM