Best wire sizing chart Ive found to date

[IdaSHO]

Just wanted to share this mornings find.

Ive seen and consulted quite a few wire sizing charts over the years, even have one laminated and on the wall of my shop for quick reference.

For 12V applications for medium to large AMP loads, this is by far the best Ive found.

Knowing your load is step one. Then determine distance the conductor must run, then consult the chart for the correctly sized conductor.

Also works great for determining solar conductor size.

http://api.viglink.com/api/click?fo...ssets.bluesea.com/files/reso...ence/20010.pdf

 

[AndrewP]

Sorry, IdaSHO but this is a misleading and unsafe wiring chart. The most important thing to realize is that is is a calculated voltage drop chart, not an ampacity chart.

For instance, The maximum ampacity for 10 ga wiring in a non-engine room environment is 60 amps, and that with the 105C rated insulation.

Your chart suggests the ampacity of 10ga wire is 140 amps. It isn't, and it is highly likely that 10ga wire with a 140 amp current would melt the insulation or itself.

Similarly, 8 gauge wiring has a maximum ampacity in the best of conditions of 80 amps. Your chart would suggest 200 amps is safe.

I recommend you delete your post. This is not a chart anyone should use to pick conductor sizes.

Just for reference, here is a proper ampacity chart applicable to the expo crowd:

https://www.bluesea.com/resources/529/Allowable_Amperage_in_Conductors_-_Wire_Sizing_Chart

And a chart to help you pick conductor sizes taking voltage drop into account:

http://assets.bluesea.com/files/resources/reference/20010.pdf

 

[IdaSHO]

Interesting.

Thanks so much for the response.

Ive updated to the link you have posted.

 

[patoz]

Blue Sea Systems also has an online Circuit Calculator, and the same thing in the form of apps for both iOS and Android. Just go to this page here for the calculator, and then look in the upper righthand corner for the apps.

 

[DiploStrat]

I am partial to this tool. While billed as a "voltage DROP calculator" you can also use it to generate wire sizes. A nice feature is that it allows you to calculate using multiple wires. This is often useful on a vehicle where a single large cable, e.g. 4/0, might be very hard to work with.

N.B. While ampacities are given below the calculator, you could, of course, calculate an impossible wire size. Typically you won't, as any drop more than about 0.5v is a bad idea for a 12v circuit.

N.B. 2 The obligatory dwh note on voltage drop: Voltage drop is only an issue at high amperages; as the amp flow through a given wire circuit drops, so too does the voltage drop. You can use the calculator to prove this. Enter some assumptions, for example, a 20 foot run, 4 AWG wire, and 200 amps. What is the voltage drop? Now, leaving the distance and wire size unchanged, run the calculator for 100A, 50A, 25A, and 10A. Now you can see why voltage drop is really only a big issue during the bulk/boost stage of charging a lead acid batter and much less important during the absorb stage. Within a certain range, voltage drop translates to a longer charge time, NOT a less "perfect" charge.

http://www.calculator.net/voltage-drop-calculator.html

 

[patoz]

I am partial to this tool. While billed as a "voltage DROP calculator" you can also use it to generate wire sizes. A nice feature is that it allows you to calculate using multiple wires. This is often useful on a vehicle where a single large cable, e.g. 4/0, might be very hard to work with.

N.B. While ampacities are given below the calculator, you could, of course, calculate an impossible wire size. Typically you won't, as any drop more than about 0.5v is a bad idea for a 12v circuit.

http://www.calculator.net/voltage-drop-calculator.html

Cool! I added that one to my 'resources' toolbox also.