Monday, Nov 22, 2004 at 19:54
Auto cable is a huge trap.
There are no direct comparisons as the stuff varies from maker to maker but roughly:
2 mm autocable is about 0.3 sq mm; 3 mm autocable is about 1.2 sq mm; 4 autocable is 1.8 sq mm - but some is 2.0 sq mm; and 6 mm autocable is about 4.6 sq mm.
When fridge makers etc specify cable they are always speaking of sq mm unless they say otherwise.
To convert copper diameter to sq mm:
1/2 diameter squared x 3.14
Thus 6 mm diameter is 3 X 3 X 3.14 sq mm. That is about 28 sq mm.
4 mm diamater is 2 x2 X 3.14. That is about 12.5 sq mm. Big but by no means overkill for the job.
Be aware that most 12 volt fridges are incorrectly connected. They mostly have 4.00 auto cable in the mistaken believe that this is the 4 sq mm typically specified. Asa a result they often have over twice the maximum acceptable voltage drop. For that job even 8 sq mm is not overkill. It's also known as 8 gauge, 8 B&S, and 8AWG - all are close to 8 sq mm.
The material referred to on Val Rigoli's Fridge and Solar site is republished there (under express permission) from my own site. Waeco often refer customers to this article.
Trust this helps
Collyn Rivers
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