Post by Gordon Harrower on Mar 25, 2011 20:46:31 GMT
This is indirectly related to my recent posts about my ignition light staying on. The consensus is that I have a short somewhere, a poor earth, or a broken wire.
The current (no pun...) question is very basic: how do I know what size a wire is if I want to buy replacement? For instance, to buy wire of the same size and color combination, I have to order it via the Internet (I'm in the U.S.). One vendor lists wires in mm sizes. Is there a way to measure the original? Are there only a few standard sizes used on these cars?
For example, I want to simply replace the LT wire between the coil and the distributor.
It could be a lengthy calculation calculating cable sizes required for a new installation, current draw, voltage drop etc. etc. to find the cross sectional area required. Here's a link www.solar-wind.co.uk/cable-sizing-DC-cables.html When replacing an existing cable, you could measure one individual strand and multiply by the quantity found in the sheathing. Here's a handy calculator for cross reference www.engineeringtoolbox.com/awg-wire-gauge-d_731.html When ordering, inform your vendor it's for old school automotive application as some new type cable has a lower Resistance and smaller cross sectional area. Hope this helps
Without getting technical...a thicker fine strand wire will always be the better option. It just costs more and may be a bit harder to manoeuvre and or bundle. Traditionally 6 volt systems had a heavier gauge wiring system with the gauge later being reduced for 12 volt systems. Think about your garden hose...the pressure involved and the diameter of the hose... basically its the same deal with electricity.
You don't have to make a meal out of this or be an electrical engineer. If the current draw is high, e.g., ignition, starter solenoid, headlights, power feed from the alternator to the battery, use a thicker fine strand wire (never use solid strand as found in your house) and if the load is light, windscreen washer motor, parking lights, interior light or your electric toothbrush, use a fine strand wire.
Locate an automotive parts supplier in your area and your should be able to purchase small spools of different gauge wire to meet your needs.
Hi Gordon; Forgive my simplicity, but unless you are an electrical engineer it becomes quite easy to replace any of the wiring on your car by simply taking a piece of original wire to your local hardware store and finding the copper stranded wire section and looking for approximately the same diameter wire. You don't want solid copper wire, and the size will be likely either 14, 16, or 18 gauge wire (smaller numbers are bigger size wires). While there buy yourself a wire stripper tool and it will be coded for the gauge making stripping off the insulation easy. Ken