Electric fan wiring and amperage question... don't want a fire (1 Viewer)

[ProwlerDriver]

Im in the midst of an engine bay upgrade and I noticed that my conversion has a dual electric fan setup with both 12 awg power wires spliced into a single 10awg power wire that is controlled by a thermostat. My question is- is this safe? the fans are rated at 25 amps each... the relay they are connected to is 80 amps but im curious if the wires can handle that draw. Should I throw a fuse on the 10awg wire just in case? or can I put an inline fuse on each of the 12awg wires? or should I look to rewire....
Thanks for any insight

 

[Seth S]

10awg is rated for 30 amps and 12awg is rated for 20 amps. Is there no fuse in the circuit now?

Rule of thumb. Ratings will vary with temperature and wire material.

 

[ProwlerDriver]

So both fans running would be 50 amps on the 10awg wire....

 

[Seth S]

Possibly. Not sure if the fans will pull max amperage all the time. But yeah 50 amps on a 10ga wire is not a great combo. 25 amps on a 12ga also no good

 

[ProwlerDriver]

I was thinking same thing... But they are only one speed so I'm not sure why they wouldn't be max draw at all times. I might just wire one up until I can rewire the whole thing

 

[Seth S]

A quick circuit sketch

 

[OSS]

I doubt a fan pulls 25A. Often the current rating for an electric device is the maximum possible draw under certain circumstances. Usually the working current is lower. 25A might be an instantaneous draw it pulls for a few seconds.
Maximum current draw ratings for wire are for continuous use at a certain temperature for a particular wire with a particular insulation.
Going a bit over the rating doesn't mean the wire will burn up- it'll just get warmer.
For 10AWG wire, current ratings can be anywhere from 15A to 75A depending on the type of wire and the chart you're looking at.

I bet you're fine with the wiring on your fans