What is that table 'condition of use'?
I mean, normally there are 2 conditions related to wire size. First, there is the maximal ampacity related to the temperature and wire insulation.? If you draw too much current, the wire will become too hot and will melt insulation. That is not related to length and any length that carries too much current will become too hot.
Then there is the voltage drop.? The wire resistance increases with the circuit length and the voltage drop increases with both resistance and current.? So at a specified current, AND FOR A SPECIFIED VOLTAGE DROP you can find a maximal allowed length. From the table capture you provided, I can only guess that the table shows the maximal length for a voltage drop percentage. What would that number be?
In a normal circuit operation, you'll want to limit the voltage drop because the load might not operate correctly if voltage is too low. It may draw too much current, which may overheat internal component, or not operate all all, etc. In a DC-DC converter application however, the circuit is made to be more tolerant. For example if we look at the Renogy DCC1212-xx spec:
It is made to operate down to 8V.? That is 33% voltage drop on a 12V circuit, so much more that usual 3% or 5% drop. So to find if a specific wire size is good, you'd have to take the minimal source voltage from the TV, add all the connection resistance to the destination (I agree that's difficult to find and it changes depending on how well the connector is inserted...), then add the wire resistance for the wire diameter to test and the wire length of the installation? (yes counting both 24 ft from source to load and 24 ft to return the current from load to source) and compute what will be the voltage at the load (the DC-DC converter) under that current.? If that voltage is above 8V, the wire will be good.
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Of course, the bigger the wire, less drop in voltage there will be.? And since it is a DC-DC converter load, lower is the voltage input, more current will be drawn, so it helps in both ways.
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That is not as the first ampacity criteria that you must not overheat the wire.? Going over the heat rating is big no-no.
jf
