Winch wire gauge clarification

[da_jokker]

Just doing some preliminary research, and came across some conflicting information that I thought I'd run by the group.

And my specific case, my winch can pull up to 400 amps. When you look at wire gauge versus amp capacities, I would need a 4/0 wire.

With that said, there are online wire calculators where you can specify the length, voltage, and amps, and it will tell you the minimal gauge you need...they report back 2 Guage (and larger).

When I look up professional winch wiring kits, it seems most of them use 2 gauge.

And yet when I search for wire length and it's effect on amp handling, the web comes back stating that length has nothing to do with amps and only effects voltage drop. In other words if a wire is not designed to hold a certain amperage, making it shorter doesn't fix that.

Yet a 2 Guage wire is supposed to only be able to handle like 115 amps.



I mean I know there are people that have used smaller wire and it has "worked"... But there are also other people that have caught their vehicles on fire because the wire couldn't maintain the load.


Just wondering if anyone knows which is true. Either a short run of a thinner wire can SAFELY handle it or it can't.

Fyi... Once I get my bumper, winch, and solenoid all mounted up, I'm is going to measure and have custom cables made (They really aren't that expensive)

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[Techun]

Duration and how it will be used matters.

Will you max load your winch? If you can position yourself to remove more line from the drum or use other advantages you can make things easier on your winch too.

 

[chtucker]

Ambient temperature and acceptable voltage drop affect wire gauge selection dramatically. Temp goes up, resistance goes up. Critical items (PCM, computers etc) require significantly less voltage drop than motors.

Front mounted winch- 2 gauge is probably OK. (even the 16.5Ti comes with 2 gauge)
Rear mounted winch something more..

Even running it in plastic conduit effects amperage ratings

 

[akturbo]

All the wires that come with winches are undersized. Do they work, yes. Will the wires heat up and smoke, yes. We haven't caught anything on fire over the years so that's a plus.

Your math is correct, you need monster wires that no one uses. I didn't want to worry about letting my wires cool down on a long pull so I opted for 1/0 and kept the wires short as possible, 5' max, may have cheated a little longer. Left a little extra in case I switch bumpers.

I have washed the engine bay since then, it's probably just as bad again after last weekend.

 

[RHeinz]

There is a big difference between #2 Gauge (#2 AWG) wire and 2/0 (00 AWG) wire.

 

[Jimmiee]

OHMs Law. The current is inversely proportional to the resistance. A threefold increase in the resistance would cause a threefold decrease in the current. (AMPS) The resistance in a wire increases as the length of the wire increases, and subsequently the resistance in a wire decreases as the length decreases. Another thing to consider is although the winch motor is rated at 400 Amps the amperage can go higher if the motor is stalled out during a pull. So with all that in mind remember when it comes to wire size bigger is always better,,, most of the time. LOL

 

[Ingridthehorrible]

Yet a 2 Guage wire is supposed to only be able to handle like 115 amps.

There's many variables that affect the amperage rating of an electrical cable, is it in conduit, is it in free air, the ambient temperature that it is used at, , the material it's made of aluminum or copper, the temperature rating of the conductor and type of insulation used. The other item that everyone forgets about is the crimp lugs and the terminals that the cables are connected to, these items all have temperature ratings and will affect the actual amp-capacity that the cable is rated for.

Some examples, the 115 amp rating is a valid number for # 2 AWG cable Type RHW as it appears in the NEC (National Electric Code, Table 310.15(B)(16), this 115 amp rating is in conduit, not more that three current carrying conductors in the conduit, with a ambient temp of 86 degree F. Type THHN cable under the same conditions is rated at 130 amps.

Now take that those same cables, with just one conductor and use it is free air, the NEC has it listed for 219 amps at 104 degrees F ambient with a 2 ft/sec wind velocity.

The thing to remember the NEC is it's about life safety and these ratings are for continuous loads, in order to insure the conductors don't over heat and start a fires.

The other item to consider is the duty cycle of the winch, at it's rated load, which most winch manufacturers don't list. Some of the top of the line Warn winches at full load say a 12K winch, full load rated a 419 amps, only has a duty cycle rating of 7/10 of a minute per a 10 minute period. As opposed to with a 2000 lbs load has a duty cycle of 2 minutes per 10 mins.

As a rule of thumb as long as you observe the winch manufacturer duty cycle ratings you should be good to go using the cables they supplied with the winch. Exceeding the duty cycle ratings you will run the risk of overheating and damaging the winch motor, contactor and cables. If you concerned you can always up size the cables, but it will not extend the manufacturer duty cycle rating.

 

[da_jokker]

Holly crap those are thick wires. I didn't realize..and those are only 1/0?

No way I could use 4/0 if that is the case.

 

[JohnnyBronco]

Holly crap those are thick wires. I didn't realize..and those are only 1/0?

No way I could use 4/0 if that is the case.

4/0 is only .46 inches diameter, not counting insulation, 1/0 is .3249

 

[da_jokker]

Wire size number is inverse. 4 gauge is 1/4 diameter of 1 gauge. Just like a 12 gauge (different scale) shotgun shell is twice as big as a 24 gauge. Caliber, however is different. A 45 projectile diameter is 1.5 size of a 30-06

Yeah, I'm comparing 1/0 vs 4/0 which is not the same as 1 vs 4 (at least that's how I understand it)

4/0 is basicaly 0000 awg

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