Looking for advice on thin wall wiring size for re-wire of SF2

[Yogi]

I want to re-wire my SF2 and have a question as to what thickness/amperage the standard harnesses should be.  Looking online, I have found 1mm/16.5 amp, 1.5mm/21 amp and 2.5mm/29 amp available.

Could someone please advise me which is the correct size to use for the job.

Yogi

 

[blab]

3mm auto wire is what you need, this bloke does bundles of solid colours and colours with a trace colour.
http://www.ebay.com.au/itm/BUY-NOW-Selection-11x-5-m-3mm-AUTO-WIRE-10-Amp-TYCAB-/172206304327?hash=item28184bac47

 

[Reggie3cl]

1mm usually means 1mm square.  That's the stuff for general wiring.

 

[drikko]

Blab is on the money there, the 5 metre lots should do you for all the general lots. Some heavier wire will be needed to the headlights which you should be adding relays too. I just bought this lot to do hornys yamagiggle and the SF3 soon, but you won't need that much wire for one bike.

http://www.ebay.com.au/itm/152137904705?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

 

[ghwallice]

I'm an electrician by trade for about 30+ years. Not an auto electrician.. 1mm2 means the combined cross section of the strands. Try for example 32/020. It means 32 strands of cable .02 mm in diameter. Calculate that yourself (pie r squared of the strand by the number of strands) (3.1417 * (.01*.01)) * 32 = ?

As stated, I'm not an auto electrician. My understanding is that auto cable can be referred back to AWG that will give you a direct current (DC) carrying capacity for each size of cable.

Almost all circuits consists of 4 basic components. A power supply (eg battery, alternator), a protection mechanism ( eg fuse, circuit breaker), a control device (eg switch, regulator) and a load (eg head light, plug in vibrator).

The particular circuit needs to be analysed for total load. eg light circuit, use high beam wattage, sum of dash indicator lamp wattages, tail lamp wattage. Say total sum of 90 watts. Current (I) equals Power (P) in Watts divided by Volts (E) (I=P/E).

90/12=7.5amps. Look at the AWG charts, find the cable that is suitable. In my case I use the next size up (circuit length and voltage losses due to cable resistance also have an impact, as does "grouping" of cables with regard to heat dissapation). Size your protection to be less than cable capacity but more than the load.

When I rewired my 3CL, I went to a BMW car wrecker and bought a shit of stuffed harnesses ect for next to nothing. This gave me cables of all different sizes, and gave me choices of primary colours with different coloured "id strands". Much better than buying 50 different rolls of cable.....

What I liked about the BMW cables was that it had a silicone based insulation that manages heat well. When I wire a sauna for example, I am required by law to use a silicon based cable.

Most over the counter cable is theromoplastic, which is temperature limited (ie v75, V90, v110 ect), doesn't seem to last long and does not have the flexibility (often only say 20 strands).

Just my basic opinion. There will be others that can explain this better, or expand on to it. But that is what the forum is about. Asking, analyising, learning and support.

Regards, Greg

 

[Gravelroad]

I have used 1 sqmm FLRY automotive wires for the general wiring. Total diameter of the wires is onyl 2mm instead of the 3mm of the ones in the fleabay adds. Those 3mm OD wires do look too bulky to me, and you might run out of space in some places, especially when trying to rewire the ND switchgear with that stuff, but might cause also trouble with the openings in the headlight shell for passing the loom strands.

 

[blab]

I think Yogi just panicked.

 

[blab]

I have used 1 sqmm FLRY automotive wires for the general wiring. Total diameter of the wires is onyl 2mm instead of the 3mm of the ones in the fleabay adds. Those 3mm OD wires do look to bulky to me, and you might run out of space in some places, especially when trying to rewire the ND switchgear with that stuff, but might cause also trouble with the openings in the headlight shell for passing the loom strands.

3mm auto wire is not 3 sqmm. More like about 1 sqmm.

 

[Gravelroad]

Yes, I know, but it's the 3mm OD which will be too bulky in some if not all places. Proper stuff has 2mm OD at 1sqmm.

 

[motoddrob]

I rewired the Motodd using the Thin walled wire, much less bulk than standard wire. I believe it's pretty much standard in euro cars.
The BMW looms you brought from the wreckers, were thay thin walled?
I got all my wiring and everything else needed on line from the UK, name escapes me at the mo.

 

[Vince]

John Wilson would use really thin wires that would carry the signs for his EIs, he would say they didnt need to be thicker as they didnt carry any real juice, much less than 12 volts. The problem was they were really easy to snap with any tugging. So they do need to take some tension as well as electrical load.

 

[Jod]

Normal electrical cable is measured in Cross Section Area but Automotive cable is measured in diameter.

Therefore a 4mm Auto cable will fit through a 4mm hole in the firewall etc...

 

[Rob]

Hi Yogi
Seems you asked a simple question and have got some complicated replies! Useful info can be found in the link below - including the volt drop issue which should be noted in respect of headlight wiring, hence 1.5mm2 recommendation for that. 
http://www.12voltplanet.co.uk/cable-sizing-selection.html.
Everything else will be fine in 1.0mm2 thin wall, apart from dynamo & regulator-battery @ 2.5mm2 plus horn-relay wiring @ 1.5mm2.
Thin wall is really good for reducing loom bundle size and can handle 105oC. 

 

[Yogi]

Thanks to all of you that replied - I have learnt stuff I didn't know from you all.  I will be fitting relays.  Just need to find the time now to get it done.  The current loom has been cut and shunted by previous owners and needs a good tidying up.

Appreciate the help provided by the forum...

Yogi

 

[Haggis]

Some gumph...