Wire Gauges

[XS1100_OEM4ME]

Granted

Not taking it for granted. That the PO of "my' bike had a friend that was a wantabe electrician, so some of the wires in "my" harnes a not OEM, thus, the finding auto grade stuff here and their, so I conced that all the OEM wires may be of the exact same type Now that I know Whiskey is useing wires from anouther yamaha harnes, he should be fine with the type of wire he is useing. As to the problem of not being the correct color code, if not planning to splice into the wires at a later time, you could just atach a pice of the correct color coded wire to the end of the replacment wire where it stops at its connector

[Laptop_geek]

Lon, both you and Geek are confusing the issue, and some of the things you're saying aren't true...

Wire size is selected for it's amperage-carrying capabilties, period. Now, there's all sorts of factors that can effect the size calculation (almost always reducing it's rating), but unless you're trying to skimp as much as possible you can usually disregard them. One big problem with automotive/vehicle wiring is there isn't any clear-cut guidelines for selecting wire sizes, with nearly every 'guide' you find reflecting that persons' idea' and few of them agreeing. If you're looking for a dead-nuts 'safe' rating, use the NEC numbers: #18 - 5 amps, #16 - 10 amps, #14 - 15 amps, #12 - 20 amps, and #10 - 30 amps. Automotive designers will increase these numbers generally about 30%, and you would be safe doing so in most cases.

Wire resistance isn't a factor in a properly-sized wire; keep in mind that the ohm difference between a #18 wire and a #12 is smaller that we can measure with the meters availiable to a home mechanic; you're talking about .006 ohm per foot for 18, and .001 per foot for #12. On a 2 amp circuit, the 18 will drop .012 v per foot, and the 12 will drop .001 v; a difference of about one-hundredth of a volt. Where you'll get into trouble is if you put too much current in the circuit; exceed the amps rating, and the wire will start to heat up. More heat, the resistance goes up, bigger voltage drop. A example of this at work is any light bulb; measure resistance through a turn-signal filament and you'll get about 2.1 ohms 'cold'. Apply power, and it jumps to 6.1 ohms, or almost triple.

Wire insulation is a non-factor in figuring wire size for a vehicle also. Your basic thermoplastic insulation is nearly always good for 60 degrees C (about 140 F), and you shouldn't be seeing temps that high except in certain places. On the XS, they did use a higher-temp-rated insulation on the leads out of the alternator, but that has much more to do with high ambient temps (being in close proximity to the motor) rather than a need due to heat generated by current. At the first plug into the rest of the harness, they switched this to 'normal' plastic wire. And any insulation reduces ampacity; compare a bare conductor in free air vs an insulated one; the bare will be rated higher. Now, somebody is going to say 'if insulation doesn't matter, why is there different ratings and higher-rated insulations are good for more amps?' Well, those higher amp ratings are there for the engineers to use in 'special' applications. The higher temp ratings are so you can select a wire that will withstand the ambient temps the wire will see. One thing seldom mentioned is the fact that nearly all commercially-available connector/terminations (plug connections, splices) are only rated to 60 degrees C, and all ampacity calculations are supposed to be done to the lowest-rated part of the circuit. Ignore this at your own peril..

This last item brings up de-rating factors. There's almost more of these than you can count, but the short answer is ampacity ratings will be affected by ambient temps (colder more amps, higher less), and is the wire in free air by itself (the highest rating), enclosed in something or 'bundled' (all reductions). You can pretty much ignore the 'multiple conductor' derate as you've only got a few circuits that operate full-time on a bike (lights, ignition, charging system), but you will have a small reduction simply if the wires are in a wrapped harness.

Wire 'flexability'.... Sorry Lon, but the XS uses the same wire type throughout the whole harness except for the mentioned alternator leads and the short pieces to the pick-up coils. I'll agree that the usual parts-house 'automotive' wire is a poor replacement for any factory wire, particularly across any point where it has to flex, but if you're using where it won't be moving it's acceptable. Aluminum wire is another non-issue, as you can't even buy it in sizes smaller than #6 anymore, and it should never be used in a automotive application.

I use THHN or THWN stranded building wire sometimes and have had good luck with that, but the difficulty is finding it in the small amounts we need and a limited color selection. Being a retired electrician, I saved 'scraps' for years, so I've got boxes full of odd pieces that I'll dig through when I need a short bit, but I prefer to use OEM-type wire. I have used that 'Superflex' wire and it's great stuff, but the cost!!!??? I recall buying some in a large size and it was over $70 per foot!

Bottom line? Never replace with anything smaller, go up one size if in doubt, and if you like to solder, use strain relief (I almost never solder vehicle connections...).

All true. But we are approaching the matter from different points of view. That is where the confusion is.

Sorry for confusing things. Everything that was said in my post was simply to explain that not all wire is created equal. A simple answer is, as stated before, use equal or larger size wire. Since the question has been answered several time I will leave it at that.

[ddragon63]

Also remember the more splices and re-connections in a strand of wire the more resistance it will build up. I've torn into things before and see 3 splices within a foot of each other in 1 strand of wire. Obviously we've all done this kind of stuff before for a "quick" fix. but I try not to make a habit out of it. if you can go A to B with new wire you'll save yourself the trouble (or someone else) of having to do it again.

[XS1100_OEM4ME]

Cs

Well, if you read CS's book, I mean post, then you would know the resistance is not a result of how many splices you have, but rather the composition of the connecting material combined with the relationship of the copper content to the related equal amount of composit in the linking and contacting elements being combined and at what temperature and elevation, so be careful with that kind os advice

Also remember the more splices and re-connections in a strand of wire the more resistance it will build up. I've torn into things before and see 3 splices within a foot of each other in 1 strand of wire. Obviously we've all done this kind of stuff before for a "quick" fix. but I try not to make a habit out of it. if you can go A to B with new wire you'll save yourself the trouble (or someone else) of having to do it again.

[cywelchjr]

Well, if you read CS's book, I mean post, then you would know the resistance is not a result of how many splices you have, but rather the composition of the connecting material combined with the relationship of the copper content to the related equal amount of composit in the linking and contacting elements being combined and at what temperature and elevation, so be careful with that kind os advice

Actually resistance IS a result of how many splices you have. I forget the formula offhand, but there is a fixed amount of loss for each GOOD splice in a wire, and for each connector in a wire, and EVEN for each solder joint in a wire (yes, solder joints are not 100% to the wire either). Also the type of material being joined goes into this, and how long the connection has been together and how much it's gotten corroded over time, which is why critical connections in electronics are often gold plated, because the extremely thing layer of gold prevents corrosion and keeps the connection as close to new as possible.

The lesson here is, the least number of connectors and splices from point A to point Z as possible to accomplish the mission is the best. Sometimes you MUST splice, but keep it to the minimum number you can and do the best splices you can, preferably with a good quality double crimper, not one of those junk things they sell at auto parts stores (and even at most electronics stores for that matter).

[ddragon63]

well then... lol

I deal with Fabricators all day who just tell me... 'my Welder don't work' so I was trying to keep it simple

[crazy steve]

Also remember the more splices and re-connections in a strand of wire the more resistance it will build up...

A properly done splice will add very little additional resistance to a circuit, but the key word here is 'properly'. If you start finding more than two splices in a run, chances are good that won't apply...

As to my 'book' , that is the merest tip of the iceberg for what you really need to know for 'designing' a circuit...

[jetmechmarty]

Steve,

You might want to point out that every splice point is an opportunity for corrosion, since most of us don't have access to environmental splices. (maybe you said it and I missed it)

[crazy steve]

Steve,
You might want to point out that every splice point is an opportunity for corrosion, since most of us don't have access to environmental splices. (maybe you said it and I missed it)

You bet, that's why I said a 'properly' done splice, although I know there's been some difference of opinion on just what that is...

I put shrink tube over any connection or splice I can, or otherwise protect it from the elements. This also gives you a 'strain relief' that will help prevent wire breakage, something tape or paint-on goo does poorly. Every splice or connection is a potential trouble spot....

[XS1100_OEM4ME]

Hey Whiskey

Hey Whiskey (love that call sign by the way) Most of this get a little crazy when us old dogs all start seeing who's is bigger Sounds like you are on the right track, replace what is needed with like wire of the same or higher gauge, keep the splices down to as few as possable and use heat shrink tubes to protect them, hit your plugs with dielectric grease and color code the new wire ends, anyway you like, to help trace wires in the future And most importaint, have a laugh at the bickering
"Noun 1. bickering - a quarrel about petty points" "to argue over petty matters" Good luck with your bike

Was replacing some questionable wire segments and realized that I used a smaller gauge wire in the splice. Not by much but still smaller. Conventional wisedom says to always wse the same gauge but I was wondering if there was any slack allowed or if some systems are more gauge critical than others. I tried a search under several keywords and nerver really found a "rule of thumb" sort of speak. By the way HNY to everybody.

[crazy steve]

"Noun 1. bickering - a quarrel about petty points" "to argue over petty matters"

You won't think it's petty when your bike catches on fire......

[XS1100_OEM4ME]

Damm

Damm that auto store wire

You won't think it's petty when your bike catches on fire......

[Laptop_geek]

You won't think it's petty when your bike catches on fire......

I think his bike already has caught on fire...

[ddragon63]

Hey Whiskey (love that call sign by the way) Most of this get a little crazy when us old dogs all start seeing who's is bigger Sounds like you are on the right track, replace what is needed with like wire of the same or higher gauge, keep the splices down to as few as possable and use heat shrink tubes to protect them, hit your plugs with dielectric grease and color code the new wire ends, anyway you like, to help trace wires in the future And most importaint, have a laugh at the bickering
"Noun 1. bickering - a quarrel about petty points" "to argue over petty matters" Good luck with your bike

You guys are pretty easy to get along with. I've tried to follow along on the R1-forum.... Those guy abandon useful information for choke slams in about 2 posts!

[XS1100_OEM4ME]

Hey Dragon

Hey Dragon, I was just having fun, home made splices should be kept down to a mim. While it is true that if you can melt the wires togather, like a weilding process does, you can cut the resistance to near 0 above the resistance of the wire it's self, but all this techno jumbo has less then nothing to do with his problem Some guys are just trying to explain why NASA is still looking for them to help get us to Mars (not you of course), the rest of us are just trying to help a fellow member get his bike back on the road

well then... lol

I deal with Fabricators all day who just tell me... 'my Welder don't work' so I was trying to keep it simple