Morris Minor Owners Club

Hi,
I'm going to start tidying up all the bodged areas of wiring in my car, could anyone tell me what would be a good current rating for general use. Examples of the application will be brake light, head light and indicator wiring, replenishing worn wires around the fuse box etc

I've been looking at www.vehicle-wiring-products.eu and they have a 28/0.30 17.5A (2mm) wire, is 17.5A ok to use for the majority of applications?

Cheers,
George

Nice and simple rule: Current (amps) = watts / volts
So...

Two indicators (1 x front + 1 x back) @ 21 watts each plus 5 watt for repeater lamp = 47 watts divided by 12 volts = 4 amp. Add a safety factor and use VWP ref 14 or 11 or even 16.

Side lights + number plates & instrument lights probably around 40 watts, so same wire.

Headlamps, assume sealed beam or halogen main beam = 2 x 60 watt = 120 / 12 = 10 amp plus safety, use ref 28, 16, or 25.

Thanks for that simmitc, with that in mind I will be ok using VWP Ref 28 (17.5A) for the applications mentioned no? By which I mean, is there any harm in using wire with a rating much higher than necessary, i.e. a 20A wire for a 10A application, my thinking is that there might be increased resistance for a weak current?

(My reason for asking is that I am on a budget and don't want to buy 50mtr lengths of every different cable rating, just spent all my money on suspension parts )

Cheers

Yes - heavier wire will be fine!

Brill, thanks

Infact, just wondering, where can one find out the wattage of various components? Does one just need to read up on each or is there a magic resource somewhere?!

George
A book ..Classic Car Electrical Systems Repair Manual by Dave Pollard (Appendix III useful information ) lists the usual components and their Wattage.
The ISBN number is 1 85960 433 1 . You should be able to borrow a copy from your local library if you put in a request/ reservation.

PM me with your address if this is not practical for you and I'll send you a phtocopy.
Bob

You don't need to buy 50 metre lengths, both VWP and Auto Electric Supplies (and quite probably others) will sell all colours by the metre, buy just what you need.

Typical ratings on a Minor:
Side lights 5 watts per lamp
Brake lights and indicators, 18 - 21w per lamp
Interior lamp 5w
Number plate 5w per lamp
Instruments 3 - 5w per lamp (usually 2)
Headlamps (later ones) 60w main 55w dip
Wiper motor, heater motor, and horn, can't remember the wattage, but ref 28 will be fine.
Reversing & rear fog (accessory fittings) 21w per lamp
Front fog / spot (accessory fittings) 60w per lamp

For reference, the thinner the wire, the greater the resistance.

Mogbob - Thanks alot for highlighting that, our local library is quite good so hopefully I can ask them to get it in.

Simmitc - Thank you for that list, very helpful. Had to think for a minute as to why thinner wire would give more resistance but have figured it out now... its been along time since physics and electronics class at school!

Cheers

Most of the power consumers are listed in the Manual.