Thinwall Cable use

[BobK]

Is 1mm thinwall cable OK for wiring lights (adding fuse boxes, headlight relays, hazards and 2 speed wipers) ?

Regards,

BobK

[Pete Lewis]

no idea other than the old systems were not designed for thin  wall currents

Pete

[JohnD]

I thought that "thin wall"  referred to the insulation sleeve.  In Triumph's day, the technology to manufacture cable could only.make a relatively thick layer around the conducting wires.

The criterion is the thickness of he conductor, often given as the cross sectional area.  See: https://www.switchelectronics.co.uk/blogs/news/electronics-automotive-cable-guide#:~:text=Generally speaking%2C the higher the,is different to the diameter.&text=Often expressed in the format,a diameter of 0.2mm.

John

[BobK]

John,

Thanks for that link. That looks a comprehensive description.

I have some thinwall which is 1mm(squared) rated 16.5A but it looks very thin so I am worried about using it.

I think I may buy some higer rated cable.

Regards,

BobK

[johny]

yes thin wall wire allows for more compact installation but does mean it needs to be protected more where its exposed or passes through holes etc. The current rating is nothing to do with the insulation thickness and another much thicker wire with a 1 sq.mm of copper conductor should still only be used for the same amount of current...

[BobK]

Johny,

Thanks. I'll check current requirements and make sure my cable can cope, probably using multiple relays for headlights.

Regards,

BobK

[johny]

Also, ideally, there should be no wire that is supplied by a fuse of a greater rating than its current carrying capacity but in our old cars this is rather difficult to achieve☹️

[BobK]

Johny,

Another useful tip - thanks. I am also looking to introduce a better fuse box (or boxes) to distribute more fuses which will hopefully address some of these issues. I will be using a lot of previous threads advice on this.

Regards,

BobK

[SpitFire6]

Hi,
Thin wall every time.

Higher current, smaller OD.
Or,
Same OD, less volt drop.
Cheers,

Iain.
 

[Wagger]

A little knowledge can be a dangerous thing here.

Thinwall has thinner insulation, so may not run as hot as wire with thicker insulation. However, if that insulation melts then it could short to chassis more easily than that with thicker insulation. It depends upon what the insulation is. Domestic Irons for instance use rubber with fabric over it. It would be disastrous to use PVC or another plastic for this purpose.

Our cars have relatively fewer wires than later cars, until CanBus etc. So what is the point of having something that can chafe through more quickly than the original design?

I always us thicker conductor sizes than recommended, especially in domestic wiring  so that burying cables under loft insulation or bunching inside plastic trunking or conduit does not cause cables to overheat. It lessens voltage drop too.

If you use Thinwall then make sure that any clamping points are double insulated.

Edited August 27 by Wagger

[68vitesse]

And be careful not to use CCA, copper clad aluminium, wire often a lot cheaper and not accurately described.

https://www.wiringdepot.com/jt-t-tech-articles/What-you-should-know-about-CCA-and-OFC-Wire

Regards

Paul.

[BobK]

Ian (SpitFire6), Wagger, Paul (68vitesse),

Thanks for the support, advice and warnings.

Wagger, I will make sure I address potential chafing points with additional insulation where required.

Paul, I read about CCA and checked that I have copper wire.

Regards,

BobK