(General) Diameter of electrical cables

[roeme]

I'm about to order a chunk of cables for various electrical work on my bikes. Aside from the beefy ones (starter,...), what's the general diameter used?

1mm˛ or 1.25mm˛ ?

[Steve]

You will have to understand that there are different methods of measuring wire size. While you are obviously using surface area, we use a numeric wire gauge size.
Here is a chart that compares the two:


I would suspect that most of the wires on the bike are 16 or 18 gauge, depending on what they are powering. 18 gauge is a bit smaller, allowing smaller bundles, but 16 gauge will handle a bit more current safely.

The wires that have to carry the most current (except for the starter, of course) would be from the battery to the MAIN fuse, then from the MAIN fuse to the ignition switch and back to the fusebox. Those wires will have to carry up to 15 amps at times. After the fuses, each circuit will only have to carry a maximum of 10 amps, so 18 gauge wire is plenty adequate.

[bonanzadave]

I hate that crappy plastic insulated wire you get at the auto parts or radio shack. Its stiff, no corrosion resistance, insulation cracks, burns and chafes. Guess I'm biased after years of using Tefzel wire at work.

http://www.aircraftspruce.com/catalog/elpages/unshieldlwire.php

[bonanzadave]

Ouch. Those prices looked steep until I scrolled up & saw that its for 1000 ft.

Surf around on ebay for tefzel wire. You can find some pretty reasonable prices.

What gauges did Suzuki use on the GS-series bikes?

Steve covered that in post #2

[posplayr]

example calculations

http://www.thegsresources.com/_forum/showthread.php?216224-Solid-State-Power-Box-STANDARD-INSTALLATION&p=1965992#post1965992

[bwringer]

I've often pondered this. Being a Japanese company, why would Suzuki use American Wire Gauge? And indeed, upon careful inspection, most of the wiring you'll find in a GS appears to be thicker than 18 AWG but thinner than 16 AWG.

Here's a conversion chart from AWG to diameter and surface area in mm. From what I can find, the Japanese motorcycle manufacturers used wire area in square mm (remember, you're measuring the conductor, not the insulation).

http://www.global-electron.com/wiresizes.htm

More info here:

http://www.engineeringtoolbox.com/awg-wire-gauge-d_731.html

According to this page, these are the wire gauges normally used in Japanese machinery
Japanese sizes
mm˛ mm˛
0.75
1.25
2.0
3.5
5.5
8.0
14
etc...

Some info in relation to BMW motorcycles, along with some charts to further illuminate/obfuscate the issues:

http://bmwmotorcycletech.info/wires&codes.htm

Stare at all this for a while, it looks like much of the wiring in a GS uses the 1.25mm˛ (square mm) wire size, which is indeed between 16 and 18 gauge. I'm not quite sure how to account for GS battery cables, which are thicker than 8awg, but thinner than 6awg. (When I need to make new ones, I use 6awg wire.) That list jumps from 8 to 14mm˛, but 10mm˛ wire would slot right in between 6 and 8awg, and I suspect that's what was used.



Anyhoo, since most of us are here in the metrically challenged US of Damn A, where everything in the year 2017 is STILL based on barleycorns, drams, fewmets, and other medieval impedimentia, AWG wire is pretty much all we can get. So we have to muddle through as best we can when making repairs.

Generally, I look at the normal load on the wire and use what makes sense. As a rule of thumb, there are very few things on a motorcycle where you'd need to upsize to 16 gauge wire, so 18 is fine for just about everything.

Here's one hand-dandy little calculator (there are many charts and calculators in t' intarwebnets). Remember, your wiring runs on a bike are pretty much all less than 6 feet, so make sure you take that into account.

http://www.wirebarn.com/Wire-Calculator-_ep_41.html

Thicker than needed wire is pain in the rear to work with, plus it may not fit where it needs to go. And you may run into added issues in areas that flex frequently. Bigger is only better if it's needed.

On a GS, wiring troubles are almost always corroded or damaged connectors and sometimes damage to the wires (from rubbing or from thumbfingered POs bumbling around in the wiring).

[roeme]

I just love this forum, you shoot off a quick question before festivities, and you get a buttload of information, both metric and medieval (you made me laugh for a good minute there bwringer)

Anyhow. We don't really use AWG on my continent, hence my question posed in conductor surface area - that's what generally is used around here. It's no foreign concept to me though, as ordering from all places around this globe requires me to convert from time to time.

Building codes here are very stringent re. electrical installations and make it illegal to install wiring below a certain diameter. My memory's a bit fuzzy, but I think its 1.5mm˛. This has the effect that smaller diameters aren't readily available, so the last time I quickly grabbed some wire from the next shop, it seemed to bulky on the bike.

Nothing wrong electrically with it of course...but yeah, some of the harnesses are bulky enough as is, and I don't need to lug around more copper than necessary on my 550s And yeah, especially at the backside it just becomes a PITA to work with.

Tefzel wire seems nice...naturally, I want nothing less than MILSPEC on my bike

Anyway, I think imma hunt for some 1.25 now.

[roeme]

Pffff, it's surprisingly hard to source an assortment of cables with many colors...

Then again, Suzuki did use ~26 different colors, so it looks like I'll need to update the wiring diagram anyway with the fewer colors I'll be most likely using.

[limeex2]

This is a great thread with good timing. Winter projects include regulator update and starter relay update. Since I am I.T. challenged, if someone could post links to those threads and any other needed electrical updates, I would be sincerely grateful. What size wiring would be correct for charging systems and there grounds?

[bwringer]

From the info on that BMW page, it looks like euro vehicles skip from 1mm2 to 1.5mm2, so yeah, it's probably going to be tough to find 1.25mm2 wire in Switzerland. I haven't found a source for the stuff in the US, either.

The best source for the correct wire in the correct colors, plus an assortment of connectors, is often an old wiring harness or two. You can pick them up dirt cheap, especially if they're damaged. Wiring harnesses are mostly model-specific, but there's a lot of commonality. If you get a harness from any model GS within a year or two of yours, you'll find most of it is useful -- one of the hallmarks of Suzuki engineering is that they didn't change anything unless they really, really had to.

If you inspect the connectors carefully, you'll see tiny slots where you can insert a terminal tool and extract the terminals from the connector shells, so quite often you can piece together what you need to make repairs from a scrap harness, or at least to make a splice in a more convenient location. The insulation is generally very high quality stuff and doesn't seem to deteriorate.

[roeme]

I have burned the whole afternoon on this topic by now.

Holy bezeejus there is so much to wiring:

- Insulation is important. It defines heat resistance, effective O.D. of the cable, and flexbility.
- ISO 6722-3 defines diameters of insulation, conductor (and some materials IIRC).
- Apparently, there are "thick wall", "thin wall", and "ultra-thin" wall insulator thicknesses defined
- There is a sh!$tload of more standard publications
- Conductor sizes are defined differently depending on the conductor alloy
- Modern automotive industry uses standardized codes to refer to cables. Closest to what I/we need seem the "FLRY-B" from the "ze germans", "GXL" from 'murica, and "AV" from the japs.
- Even the angle and thickness of the color stripe for two-colored cables is standardized in modern wiring.
- The colors of these cables generally tell their function, regardless of the vehicle.

As said earlier, I found it next to impossible to get a color assortment of cables online. Either the lengths are way too short, very few colors are included, or it's simply too pricey.
I also couldn't find reliable information on insulator thickness. Either you get AWG, or mm˛.

I was able to find a source for FLRY-B cables here locally, so I went down this rabbit hole. For now.

FLRY-B:
"FL" stands for Fahrzeugleitung (vehicle wire) and is a prefix common to all these cables.
"R" means reduced insulator thickness (that's what I want on my bike).
"Y" designates plasticized PVC. The "tefzel" (EFTE) wire that bonanzadave was referring to would have a "7Y" in this place.
Finally the "-B" version is more flexible than the "-A" version, by defining thinner strands (consequently, -A is rated up to ~220Volts, while -B may carry no more than 60V).

I just hope I can finish ordering today

bwringer, you're right, 1.25mm˛ seems to be an odd-ball size around here. Also, recycling old harnesses is a neat idea.

[steveb922]

Some interesting stuff here:

http://kojaycat.co.uk/epages/950000457.sf/en_GB/?ObjectPath=/Shops/950000457/Categories/Cable

[posplayr]

I have burned the whole afternoon on this topic by now.

Holy bezeejus there is so much to wiring:

.

Welcome to engineering

[roeme]

Taking voltage drop and product availability into account, I have now ordered both 1mm˛ and 1.5mm˛ FLRY-B wires, 2 colors of each, as a starting point.

To help distinguish the cables, I'm going to use cable markers like these:



Since I don't yet rewire the bike(s) from scratch, but rather fix PO botches and make various small-time mods, I deem this sufficient for the time being.

I will then select the wire according to the current it will have to carry. From what I have learned so far it seems that 1mm˛ FLRY-B will/must be able to carry 16.5 amps, and 1.5mm˛ 21 amps. Glancing from posplayr's SSPB thread, this seems plenty. I'd even go down to 0.75mm˛ (~AWG 20) for the dash, but let's not get ahead of myself just now.

Will update this thread with install experience when the cables arrive.

[bwringer]

This topic is perfect timing for our little GT250 cafe racer project.
The bike has all LED lights & will have a from-scratch wiring harness.
I would like to use the same colors & tracer colors that Suzuki used.


That kojaycat website looks interesting.
Does anyone have a link for a US retailer of the thin-wall wires that includes tracer options?

It's gonna get seriously expensive... here's thin-wall Tefzel in all the colors of the wiiiiiind...

https://www.prowireusa.com/c-59-m22759-32.aspx

If you're building from scratch, you'll probably want to settle on Deutsch or Weatherpack connectors, so you'll need an assortment of these ($$$) and the correct wire strippers and crimpers ($$$$), not to mention heat shrink breakout boots ($$), heat shrink tubing, etc.

Another place with lots of supplies:

http://www.riwire.com/

If you're looking for replacements for the OEM connectors on your GS or other motorcycles, a couple of places to look:

http://easternbeaver.com/Main/Elec__...onnectors.html <== mostly the stuff used on newer Japanese bikes

http://www.vintageconnections.com/ <== supplies for older bikes, like our Suzukis.