Wiring gauge

[MrIan]

Hi everyone, after a bit of info regarding cable/wiring wire size.
Whilst removing an old faulty unreliable alarm from Boris Minor I discovered that sometime in the past his lighting circuit has been overloaded (additional lights added at some time I assume). The wires that have distorted insulation are the RED feed to the rear sidelights and the BLUE feed to the front headlights.
Does anyone one know what rating these wires are so I can replace them ?
Cheers

Oh nearly forgot, Boris is a 1959 so lights are on the pull switch.

[simmitc]

Side lights are 5w so at 12v draw about 0.5 amp (very rough, I'm not going into decimal places) apiece, so if you go for standard 6-7 amp cable. Headlamp are 60w each = total 10 amp so use 17.5 amp cable. Those ratings are chosen as they are readily available stock sizes. You need mutli-strand automative cable/ I could quote number of strands and cross ectional area, but the reality is that most places will sell by the amperage rating. Modern "thinwall" cable is also perfectly OK, just not period. Have a look at Vehicle wiring Products or Auto Electrical Supppies, but have good web sites and allow you to purchase the correct colour and length that you need plus the connectors to join them.

[MrIan]

Cheers thanks. Maybe it's to do with the overall de-reg on cables that I think happened a while ago or just the fact the insulation is distorted on those 2 conductors but they look bigger than 1.5mm yet 1.5mm at 12V will carry 15amp so 180w .
I'll do some digging and see what i've got.
Cheers.

[IslipMinor]

The sidelight cables are 14/0.012 or 14/0.3 (1.0mm) in modern parlance, and the headlight feed is 28/0.012 or 28/0.3 (2.0mm).

[MrIan]

Cheers, the wires have now been replaced. I was confused as to what could have been added to the rear sidelight circuit to have overloaded the wire. I found that a floor repair (weld) had caught the cable right at the point where it was clamped to the body with the metal tang. As the rear sidelights are unfused this short circuit had melted the insulation off of the wire completely hence all feeds to the rear have been changed. The headlight circuit (also unfused) had a wire tie wrapped to a brake pipe tightly, thus when it overheated (car previously had spotlights in a spoiler) the insulation melted and another short to -ve !!
Good job I didn't use old Boris over the winter as he might have got too HOT !!!

[mogbob]

Future disaster averted. Well done detective.
Have you covered the metal tangs for the " belt and braces " approach. Either straight forward insulating tape or a short length
of sleeving , cut to size. http://www.autoelectricsupplies.co.uk/p ... ategory/66.A quick blast with the heat gun or the hair dryer and tuck the wires / loom behind again.
Bob

[MrIan]

Yes I use sleeves over the tangs then also make sure they are bent round the loom and not just used to crush it !!! Only had Boris for just on 12 months and only found this due to removing an unreliable alarm !!.