What gauge wire to use?

[Leatherneck]

What gauge wire to use?

Headlights
Taillights
Brake lights
Horn
Fuel pump
Oil temp sender
oil cooler fan
Starter to Alternator
Starter to Switch

What else am I missing?

[Ol'fogasaurus]

Battery cables both positive and ground. Also a power cutoff switch.

http://www.nooutage.com/vdrop.htm Voltage drop calculator.

http://www.mydune-buggy.com/forum/viewforum.php?f=17

Dale M's site. Has good stuff on electrical.

Lee

[Dale M.]

What gauge wire to use?

Headlights ---- 14 gauge
Taillights ---- 16 gauge
Brake lights ---- 16 gauge
Horn ---- 14 gauge
Fuel pump ---- 14 gauge
Oil temp sender ---- 16 gauge
oil cooler fan ---- 14 gauge
Starter to Alternator ---- 10 gauge
Starter to Switch ---- 10 gauge

What else am I missing?

Ign switch to coil ---- 14 gauge
Alternator charge light ---- 16 gauge

IF you are looking for one size fits all use 14 gauge ( except where I have spec-ed 8 or 10 gauge) . 14 gauge is over kill in some places but its better to go larger then smaller....

Also get many different colors of wire when doing wiring its easier to sort through 2 or 3 duplicated colors than have whole system one color (if you have only one color- use number tags on both ends) ....

Use best quality wire crimping tools you can afford (preferably ones that have indenter dies.... And do not scrimp on heat shrink tubing and plastic wire ties....

Lots of diagrams and stuff in pic gallery too.... Use the "search" feature...

http://www.mydune-buggy.com/gallery/index.php

Dale

[Leatherneck]

What gauge wire to use?

Headlights ---- 14 gauge
Taillights ---- 16 gauge
Brake lights ---- 16 gauge
Horn ---- 14 gauge
Fuel pump ---- 14 gauge
Oil temp sender ---- 16 gauge
oil cooler fan ---- 14 gauge
Starter to Alternator ---- 10 gauge
Starter to Switch ---- 10 gauge
Ign switch to coil ---- 14 gauge
Alternator charge light ---- 16 gauge

IF you are looking for one size fits all use 14 gauge ( except where I have spec-ed 8 or 10 gauge) . 14 gauge is over kill in some places but its better to go larger then smaller....
Also get many different colors of wire when doing wiring its easier to sort through 2 or 3 duplicated colors the have whole system one color....
Use best quality wire crimping tools you can afford (preferably ones that have indenter dies.... And do not scrimp on heat shrink tubing and plastic wire ties....
Lots of diagrams and stuff in pic gallery too.... Use the "search" feature...
http://www.mydune-buggy.com/gallery/index.php

Dale

Thanks for the help on this. Another question. From the switch there are two wires going to the Starter (for most). One going to the starter for 12Volt power and one going to trigger the solenoid. Would this be right?

Starter switch (B+)to solenoid for 12v power ------ 10 gauge
Starter switch (ST) to solenoid spade bit ---------- 14 gauge

Possible Sticky material?

[Marc]

The cross-sectional diameter (in mm²) of the conductors is marked on the diagrams in the Bentley manuals. Here's a conversion chart to AWG: http://www.ddacables.com/technicka-podp ... rurezy.php
This is technically only correct for solid conductors, but it's close enough - especially if you go up one size (lower number) in AWG.

Best source of most wires IMO is to salvage a harness from a scrap VW (buses are particularly useful, lots of extra length).
http://www.shoptalkforums.com/viewtopic ... 4&t=136169

[Dale M.]

Though MARC is probably correct in the conversions from Bently manual for metric to US Wire gauge, my recommendations are from actual current measurements of devices when powered and using amperage/footage charts and tending to go UP one gauge size larger when in doubt... When using my method, you will probably never use a wire gauge that is to small.... Maybe to big, but that does not hurt anything.... Auto manufactures and other industries tend to use the smallness safest wire gauge possible, but its a expense issue.... For the one time wiring of a bug/buggy/rail, a few dollars more is not a project killer....

IF you try to short cut and use cheap wire and components and terminals and really poor crimping tools it will come back to haunt you many times..... Did my fiberglass dune buggy 10 years ago, everything worked first try and have not had a single issue with wiring other than once I did something stupid under dash (while standing on my head) and blew a fuse.... IF you have ever been under the hood of a completed fiberglass buggy you would understand....

FYI....

Head lamps HIGH beam filaments (65 watt) = 4.5 amps
Head lamps LOW beam filaments (55 watt) = 3.5 amps

Turn and marker lamp bulbs
1157 bulb - turn signal/stop filament = 2 amps
1157 bulb - marker/tail filaments = 0.50 amps
1156 single filament bulb = 2 amps

LED's... ( 44 led style 4 inch round tail light assembly )
Stop/ turn section = 0.445 amps
tail/marker section = 0.023 amps

And remember these are single filament values if you are running both lamp filaments through same fuse everything is 2X, or with four filaments like tail/markers its usually 4 filaments on same circuit (parking lights?) so it would be 4X...

Dale

[Marc]

Dale, did you even look at the results achieved by following my suggestion? It's true that many cars use smaller wire than they should to save a few dollars, but ACVWs have always used wire that's of adequate size for the (stock) load.
Examples:
Headlight wires are 2.5mm² - that crosses to 14GA in the chart, same as you specified.
B+ wiring is 6.0mm² (10GA), again the same.
Taillamp wires are 1.0mm², that's 17GA in the chart so of course you'd go to 16GA since 17GA is not a commonly found size...but the stock 1.0mm² would be good enough unless you have additional lamps.
The smallest wire VW uses is 0.5mm² (20GA) and it's more than adequate for the places they use it such as warning and dash lights - the only reason to go larger would be for added physical strength, but 16GA would still be overkill - one step up to 18GA works just fine. I wouldn't want to run any heavier on the dash light circuit since it has no fuse protection - better to smoke a length of wire than a headlight switch (this is one place where too big of a wire can do harm).
Term 50 wiring should be 4.0mm² (12GA) as it is stock, or heavier. Lighter than 12GA would be acceptable to control a starter "booster" relay near the solenoid, but the input & output wires of the relay should still be 12GA.

[Dale M.]

I have almost 40 years in telecommunications and wire gauge was a every day factor in my work "everything" was calibrated for "use" and amperage factored in ....

All the rules are the same if you use metric or US wire gauge.... Its all about "capacity of conductor" (not over heating or excessive voltage drop).... The rules in my industry was always "if in double always go one size larger in wire gauge"...

All my wire sized are base on application charts similar to this...



Yes there is a "jillion" of them out there.... And all have slight variation, but most will get one into ball park for load capacity per application...

http://images.lmgtfy.com/?q=wire+gauge+chart

One must also keep in mind not all wiring applications are Industry standard for the particular car one is building.... I for one buy my wire in bulk from large distributors and assign my own colors and my work is mostly in dune buggies and rails and custom off road builds (building full harnesses from nothing)... Very rarely venture in to stock stuff unless its to repair butchered wiring done by unskilled persons or to repair harnesses that rodents have chewed on, like the BAJA I purchased some time back and rodent decided to eat wiring harness completely through right where if comes out of rear quarter panel under rear seat.

This is as close AS I have ever come to "Bently or European wiring schemes"...

http://www.e38.org/understanding%20euro ... agrams.pdf

Dale

[Marc]

...All my wire sized are base on application charts similar to this..

If that's true, you apparently expect the charging system warning light wire to need to handle 10 amps, and headlamps would be fine with 18GA...

My point is simply that the stock wire sizes used on, say, a `70 Beetle can be used as a guideline even for "custom" work. If you were to step up one AWG size from there you'd probably be covered even for upgraded headlamps, etc.

[Dale M.]

Why are you picking the "fly poop out of the pepper".... I do not understand what the issue is here....Are you just in a mood to argue......I buy 3-4 practical wire gauges in bulk rolls and and have about
5 colors on hand, That makes a inventory of about 15-20 rolls of wire, if I use 16 gauge wire instead of 18 gauge wire what difference does it make......

I try to give practical wire sizes that are useful for more than one "SPECIFIC" application to make it easy for someone wire up their ride and be able to walk away with a grin on their face.... And not have to buy a lot of specific size (gauge) wire...

Hell I could wire the whole car in 10 gauge and everything would work just as well, but wire bundle (and cost) would be enormous....

Dale

[Marc]

...Are you just in a mood to argue...Dale

I guess I am. You seem unwilling to acknowledge that your beloved charts don't always yield the right answer (like the cases I've already cited). Too large a wire can cause problems; again I've given an example, although in most cases the larger concern would be the lack of flexibility.
If you are incapable of recognizing the points I've raised, it's pointless to continue the discussion. The info's there for those who choose to read it.




"Before you criticize someone, you should walk a mile in their shoes. That way, when you criticize them, you’re a mile away and you have their shoes." -Jack Handey

[Dale M.]

I have recognized your points and I feel yes they are valid, but in the ease of simplifying doing wiring I have remove several wire gauges from the equation so as to make it easier for the "average joe" get something put together and running.... I know where you are coming from but the point is it does not simplify whats to be done for the person actually trying to put a few wires together...

Look at it this way, the wire line telephone you pick up for dial tone when your cell phone was forgotten of has a dead battery, or the actual cellular system, or the fiber optic networks the carries this internet we use, IF I were to sit here and try to explain it to you on the technical level how soon would it be before your eyes glaze over..... The reason these systems work is because I am a trained technician and I have invested a good portion of my life making it work so you have the privilege of instant access... And along the way just maybe I have learned just a little about electrical things, and yes I can thrill or bore you to death on what I know and what I have done..... But it does you and me nothing because "joe" still can't wire his buggy.... I have pretty much rounded up most wire sizes to within practical limits to get things to work for "joe".... Why do you want to make it hard for "joe" you real purpose here should be to make it simple.... Whether its a 18 gauge wire or 16 gauge wire operating oil pressure lamp or alternator lamp does not mean much for "joe" all he wants is for it to work.... He does not care about what size wire it is as long as its sufficient for his application....

I know you are probably factory trained mechanic and you were taught to go by the book, and that is well and good for the work you are doing to meet the expectations of your employers and customers... But rigidity some times can be a point for lack of success... Many time If I had not deviated standard procedures or sough the authority to change things ENGINEERS flubbed, half your Internet or cellular services would probable not be working for you (ok so its a exaggeration but I am trying to get your attention)... You have to be come a little more flexible....

Dale

[Marc]

No, I am not factory trained. I do have more than passing knowledge of electrical theory, however - I'll put my experience as an electronics tech and nuclear reactor operator up against yours any day, but this isn't about credentials.
I can't see how simply following what's been proven to work on millions of VWs will in any way complicate things for "joe"...let's just agree to disagree and quit wasting bandwidth.

...it's pointless to continue the discussion. The info's there for those who choose to read it...

[Dale M.]

Agreed...

And I did (do) recognize your were formally trained in some filed where precision and dedication was a demanded....

Maybe now we should move on to "what wire colors to use"?....

Dale

[Leatherneck]

Thanks guys, both have been a big help. This "Joe" is learning and doing a much better job of wiring from scratch because of your help.