[AT] Tractor wiring

[Mike Sloane]

One other thing: house wiring is solid copper, but for vehicles of any 
kind, you should use "stranded" copper. Also, it is my understanding 
that stranded wire will carry more current than solid wire of the same 
gauge (something called "skin effect"). The reason for using stranded 
wire is that it is better able to handle the vibrations and doesn't 
"work harden". OK, two things: resistance losses for direct current are 
higher than for alternating current, so for longer runs you need 
relatively thicker wire. Fortunately, most tractor wiring is very short, 
that that isn't usually an issue.

Mike

Spencer Yost wrote:

> Mattias is right, the formula holds true for any type of electrical
> circuit.   Be sure to realize resistance, an important additional load on
> the circuit that may change your decision on wire size, increases with the
> length of the wire.
> 
> As for wire sizes, 10 ga. is used for charging circuits on virtually all
> vehicles with regular duty alternators and alternators are usually the
> highest wattage circuits (400-800 watts) on a vehicle.  So I use 10 ga for
> any type of charging circuit, I use 10 ga (and a relay!) for modern
> high-intensity lamps and I use 12 ga. for for lower output lights if there
> is more than 2 on the circuit.  I use 14 ga. for everything else.  If I am
> unsure, I use 10 ga and a separate switching circuit with a relay.  Heavy
> duty alternators, if I had ever wired for any, would probably get 6-8 ga
> wire.
> 
> I have no engineering calculations to back this up but this is what I have
> learned to use over the years and seems to match pretty well with what is
> used in practice by manufacturers and hold up to a few offhand resistance
> and wattage calculations I have done on the back of a tool package label.
> I am sure others have some better ideas that maybe are tested or calculated
> that may give you a better degree of comfort than "This is Spencer's system
> and it works for him because nothing has burned down"  (-;
> 
> Spencer Yost
> Owner, ATIS
> Plow the Net!
> http://www.atis.net
> 
> *********** REPLY SEPARATOR  ***********
> 
> On 11/16/2004 at 10:18 PM Greg Hass wrote:
> 
> 
>>After several years of procrastinating I am going to completely rewire my 
>>Farmall 856 with a year-a-round cab.  I can rewire a house, a barn or a 
>>shop.  However, when it comes to tractor wiring I can't figure the size of
> 
> 
>>wire to use when it comes to wiring the various components.  For instance,
> 
> 
>>I want to add some halogen lights, some hooked together and some wired 
>>singly.  Also, I want to add a heater and possibly get the circulating fan
> 
> 
>>running, which has never worked since I've owned the tractor.
>>
>>I want to use adequate sized wire, but on the other hand no bigger than 
>>needed as the heavier wire is harder to work with.  Does anyone know of a 
>>chart, or source, or rule of thumb on how to figure such things?  For 
>>instance, with house wiring "amps x volts = watts", but I'm not sure the 
>>same formula would apply to a 12-volt system.
>>
>>Greg Hass
>>
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> 
> 
> 
> 
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-- 
Mike Sloane
Allamuchy NJ
mikesloane at verizon.net
Images: <www.fotki.com/mikesloane>

The whole problem with the world is that fools and fanatics are always 
so certain of themselves, and wiser people so full of doubts. -Bertrand
Russell, philosopher, mathematician, author, Nobel laureate (1872-1970)