Wiring loom wire gauge and colour

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dp
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Wiring loom wire gauge and colour

Post by dp »

Does anyone know where I could find out the gauge of the various wires in the loom please?

I'm going to make my own loom as all the wires in my engine bay are burned and it's a good time to do the whole lot properly, replacing 20 years of ad-hoc additions.

Also, was there a BMC standard colour scheme that I could follow for functionality that wouldn't have originally been in the Minor? Eg. ammeter, water temp, rev counter, reversing light etc?

I could just make it up as I go along but would like to follow a standard if I can.

Also, what's the most reliable type of connector. Not worried about originality here but reliability :)

Thanks
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PAULJ
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Post by PAULJ »

If your car is standard buy a loom. It will save you a lot of work and will probably be cheaper. you will have all the colours. As for connectors solder and heat shrink as many connections as possible. Most electrical problems come from connections
dp
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Post by dp »

It's not standard, different engine and allsorts of component repositioning. There would be so much extending and shortening plus additional wires that I'd prefer to make from scratch, eliminating unnecessary junctions by using single runs.
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mike.perry
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Post by mike.perry »

Autosparks, and probably other companies, will supply a standard or custom wiring loom to include the extra wiring for reversing lights, gauges etc, whatever you specify. The colours will be to industry standards. Provided you give them the specifications and position of components then they should be able to meet your requirements
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simmitc
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Post by simmitc »

Yes, there is a standard colour scheme for a wiring harness. Any of the workshop manuals will have the wiring diagram with colour codes, and it's a very good idea to follow it. There was also a very good and useful diagram posted on this board. If I can find it, then I'll post a link - unless someone else beats me to it.
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Post by simmitc »

I've found the post with the diagram:
http://www.morrisminoroc.co.uk/index.ph ... 918#125918
but unfortunately the picture has disappeared and now just says "image". Does anyone know where this excellent diagram went, or have a copy of it?
teenoes
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Post by teenoes »

The following link provides cable colours from 1983 onwards as specified by BS-AU7a - I have no idea what is the correct BS for older cars but perhaps someone on here knows - at least some colours differ from what I have got in my 1960 Minor:

http://www.dimebank.com/LucasColours.html

The following one is obviously by the same author as the above one:

http://www.team.net/sol/tech/LucasColours.html

Here is another one - but also not matching to what I have got - but here it says it is based on BS-AU7 - no idea when that was introduced:

http://www.jcna.com/library/tech/tech0014.html
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bmcecosse
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Post by bmcecosse »

Unfortunatel - Barry seems to have disappeared at the moemnt - and I can't find his email addy either although I'm sure I have it! I also thought I had taken a copy of his excellent diagram - but can't find it either!! So annoying! Grrrrrr
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PAULJ
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Post by PAULJ »

I tried autospark. I emailed them requesting a quote for a loom for my modified car. The reply I got back was a p... take. I didn't get a price just some stupid questions like " What way up is the number plate light" So not helpfull at all
mike.perry
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Post by mike.perry »

Strange. They have been most helpful when I have ordered from them, including supplying the excellent trafficator/indicator wiring diagram.
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autolycus
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Post by autolycus »

I, too, am very surprised at the remark about Autosparks. Is it just possible that "PAULJ" didn't understand the significance of questions they asked, or didn't provide them with enough information? They may, for instance have thought that only simple questions were appropriate to identify his car.

Perhaps a phone call first, to establish exactly what information they need to provide either an estimate or a firm price, would have been worthwhile.

They remain one of the best specialist suppliers I've used.

Kevin
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Post by RogerRust »

PM sent
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This message board is like a family - you can't choose the other members!! But remember engine oil is thicker than water.
bigjohn
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Post by bigjohn »

iv got this if its any use,i know its for an alpine but it sorted my indicator problem out a treet
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British Wiring Colors Explained

Sometimes the English do something that makes so much sense you have to wonder where the idea came from. If you ever had the opportunity to look under the hood or dash of your British car you would have seen, among other thing, lots of wires, the newer the car, the more wires. All these wires are different colors; some are multi-colored, and all for a very good reason.

Sometime before WW II (I've been unable to find out exactly when) the British instituted a wire color coding system for all the cars manufactured in their country. It started out very simply to identify the basic electrical systems and has grown, as the cars became more complex.

A black colored wire indicates a ground circuit wire, the wire connecting an electrical unit to ground, usually the car's metal chassis. A brown wire is HOT or one that always has power and is not fused. These are the big wires that carry battery power to and from the fuse block, voltage regulator and generator. There are sometimes also smaller brown wires that run the wiper motor park circuit.

This is where the extra complexity comes in. Since the brown wires run different circuits it was necessary to differentiate the wires for each. The TRACER is a different colored stripe running the length of the wire to indicate the particular job of that wire. Therefore a brown wire with a yellow tracer is for the generator warning light while brown with a white tracer is for the ammeter.

As a quick note, the colors are abbreviated in the various manuals. Some are obvious like R means red, Y means yellow, G is green. Since black is denoted by B, N was used for brown and U for Blue. So a brown wire with a white tracer (power to the ammeter) would be NW, brown with a light green tracer is NLG (the windscreen wiper park switch).

Blue wires are for the headlights with plain blue being power to the dimmer switch, while the power from the switch is denoted two ways. Blue/red (UR) is for the low beams and blue/white (UW) is for the high beams and the indicator lamp.

The use of tracer colors is especially evident with the white wires. White denotes a circuit that is powered when the ignition is on. A plain white wire runs the fuel pump, ignition relay, and various fusebox connections. White with red (WR) is the power to the starter solenoid, and white with green (WG) is power to the radio. White with black (WB) is power to the ignition coil unless there is a ballast resistor then the wire is white with light green (WLG).

On the early cars with few electrical accessories green was the color for fused power from the ignition for such items as brake lights (GO or GP) and the fuel gauge (GB). When turn signals were added Green was used here also, green/white (GW) for right turns and green/red (GR) for left turns.

As customers demanded more conveniences the wiring grew in complexity. Now, along with green, light green is also used as the base color for various applications like screen washer pumps (LGB) and hazard warning lights; light green with brown (LGN) is the color here since the hazard light system needs an always hot circuit to operate without the key being turned on.

For the next extra color they couldn't use grey since G was already for green, so S for slate was the obvious (?) choice. Slate indicates circuits that are hot when the ignition is off, such as emission control power. Purple is for always hot circuits with fuses such as courtesy lamps (PW) or key buzzers (PG or PK (K for pink).

So, you see, there is a method to the madness. If you know the system you can even sort out a wiring harness that you never saw before, with no wiring diagram, for a car that someone else dismantled 20 years ago!
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dp
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Post by dp »

teenoes wrote:The following link provides cable colours from 1983 onwards as specified by BS-AU7a - I have no idea what is the correct BS for older cars but perhaps someone on here knows - at least some colours differ from what I have got in my 1960 Minor:

http://www.dimebank.com/LucasColours.html

The following one is obviously by the same author as the above one:

http://www.team.net/sol/tech/LucasColours.html

Here is another one - but also not matching to what I have got - but here it says it is based on BS-AU7 - no idea when that was introduced:

http://www.jcna.com/library/tech/tech0014.html
Most useful, particularly the last one in colour - thanks :)
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teenoes
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Post by teenoes »

:D :D :D :D :D
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dp
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Post by dp »

Ditto the description from BigJohn, I'll print that off and keep since it helps to keep the main ideas in one's head.

Funnily enough - and I'm sure there are a few that have also absorbed it over time - I've partially memorised a lot of the original loom anyway which is why I'll replicate it.

A fair few of the extras in my car use bits of the old Lancia loom which has a tigerstripe system Eg 5mm black, 5mm yellow and so on down the plastic.

Okay, while on the subject, what connectors are best, the brass type or the grey metal?
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mike.perry
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Post by mike.perry »

The main drawback with the old fabric covered wiring was that after 30 years every wire was black, which was why I specified plastic covered wiring for my Series MM
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