Injector wire size??

[hks7mgt]

Rhyno - definately OD as i'm also using a couple of 6mm OD (50amp) with fusible links for power circuits to the fuse panel.

I can beleive the extra weight will be a factor with a light car.

Cheers gents

[thechuckster]

weight for one wire wouldn't be an issue, but for a whole chassis+engine loom, if you can remove several kilos of wire & insulation then it can contribute (as part of a larger weight reduction scheme) to vehicle performance.

[Rhyno]

hks7mgt - You should be sweet then.

thechuckster - Excatly where I was coming from, it all adds up in the game of speed

Happy Days

[Flex]

Rhyno, when you talk about cable size you should refer to it in mm2 (gauge). OD or ID doesn't mean much as OD could be referring to a lot of plastic sheathing and ID is very hard to measure. Also when they spec in cables for automotive wiring they used use a gauge that will hold up to the fuse ratings. e.g. If you use a 0.5mm2 you would use a 10A fuse or less. I've listed below some of the common wire sizes and their currents (at 40 degrees temperature):
0.3mm2 = 8A
0.5mm2 = 11A
0.85mm2 = 14A
1.25mm2 = 19A
2mm2 = 26A

In regards to temperature de-rating:
You can use this list as a rule of thumb:
50C 0.88 * rated current
60C 0.75 * rated current
70C 0.58 * rated current
80C 0.33 * rated current

In you application (injector) I would use 0.5mm2 which allows for 4 amps at 80 degrees C

[hks7mgt]

That information is handy thanks.

But, i've never heard of a wire rated in that way. Would it be wrong for me to ask would a 0.5mm2 cable be equivilant to in say a 2.5mm or 4mm cable (OD) approx of course (taking in your comment above that some plastic sheilds could be thicker than others)?

I went into the auto electrical place (a good one) and paid for the wire they use. It was rated in the current it can handle and it just worked out that 4mm OD was 15A and 6mm OD was 50A. I'd assume 0.5mm2 is the 2.5mm OD (or what is commonly one size smaller than the 4mm).

I'm just personally interested now as all my wirings is done.

[oldcorollas]

afaik, wires are always rated in that way.. mm^2 of conductor

in fact, the mm^2 is often printed ON the insulation

the other way is in "gauge" liek this
http://www.dansdata.com/images/io030/wire640.jpg

check otu this table. http://www.engineeringtoolbox.com/aw...uge-d_731.html
has amrican wire gauge (AWG) vs diameter vs mm^2 (cross-sectional area)

eg 0.52mm^2 = 0.81mm diameter (of copper) = 20AWG

but then you have multistrand, which is labelled differently, like 24 x 0.2 = 24 strands of 0.2mm diameter

[hks7mgt]

i never looked so far into cables before. I can understand how different they all are and therefore a need for a standard and for professionals in the industry to be able to follow those standards accordingly.

I first took some home electrical cable (you know the green, black and red in the single white sheild) for use for my car, but later learnt it was not suitable for auto-electrical use (althought it may have worked) as there were less strans for the similar cross section which would be harder to bend, harder to solder and just not auto-electrical cabling.

did i make the right move here?

[Flex]

Home electrical wire wouldn't be the best wire for automotive wiring, mainly due to it's temperature rating. It may be rated to 10A but that would be at temperatures less than 40 degrees C. So not using home electrical wiring was the right move.

[timbosaurus]

Auto cable is funny.

Yes, the right way to measure is in mm^2 (cross sectional area). That's the only real way to understand how much conducter is in the wire.

Simple explanation of AWG (gauge) is that it's just a non-metric scale for mm^2 (cross sectional area).

As is always the case, some 'tard goes and screws thing up by introducing a non-standard way of measuring auto cable. Hence, people refer to it as 2mm, 3mm, 4mm, 5mm etc cable.

A reputable auto elec would only call cable Xmm if it was essentially what people understand Xmm auto cable to be.. ie: 4mm ~= 1.85mm^2, 5mm ~= 2.9mm^2

I have seen 4mm cable at supercheap (incidently called 10amp cable!) where the conducter would not have been even 1mm^2.

Note: never accurately measure cable as '5amp' or '10amp' cable. Basic reason is that current capability has a lot more factors than wire diameter alone.