TR3 cable sizing

[Graham]

UOV has had a nice new braided wiring loom installed, however whats not so nice is the original braided cable 'tails' from the headlights/indicators/horns that connect to it so I was going to re wire these with new braided cables, any body any idea what size cable I need please. as per http://www.autosparks.co.uk/electrical-components/cables/braided.html

[iain]

Hi Graham you need to size the cable to the power of each light being supplied.

 

Simply, Watts/Volts = Amps

 

So

 

If you have standard candles (sorry headlamps)

 

45W/12V = 3.75 Amps per candle/headlamp. Add a safety factor of "X" % I cant remember what is advised, but that means the "9 / 0.30" which can handle 5.75 amps, should be fine in the correct colour combination for that light.

 

Iain

[Graham]

Hi Graham you need to size the cable to the power of each light being supplied.

 

Simply, Watts/Volts = Amps

 

So

 

If you have standard candles (sorry headlamps)

 

45W/12V = 3.75 Amps per candle/headlamp. Add a safety factor of "X" % I cant remember what is advised, but that means the "9 / 0.30" which can handle 5.75 amps, should be fine in the correct colour combination for that light.

 

Iain

quote thanks Iain thats what I was thinking but been a while since I used Ohm's law !

[tthomson]

Should you wish to use more powerful headlamps (e.g. 60W - standard headlamp bulbs) then you should really use a heavier wire to handle the current. Also, the voltage drop along a cable is directly related to its current carrying capacity (Ohm law again). To minimise this voltage drop thicker cables are better

 

60W bulbs need 5 Amps - safety margin means 7 Amp capacity (minimum).

 

Good luck

TT