Gauge of extension cord

[RonRN18]

My trailer came with, what I believe to be, a 25-foot 30-amp power cord that connects to trailer with a round connector with locking ring... fairly standard for trailers from what I've seen. My question comes to the use of an extension cord with this cable. I've looked at extension cords that are 50-feet long, as there is a camping space where I know it will be around 75-feet or so away from the nearest I can park my trailer. I've looked up charts listing appropriate gauge wire for different length runs at single-leg standard voltage. For up to 50-feet, it recommends 10-gauge wire. For 75-feet, it recommends 8-gauge wire. For 100-feet, it recommends 6-gauge. My assumption is that the power cord for the trailer is 10-gauge. 50-foot RV extension cables are also 10-gauge. This jives with the chart I looked up... BUT... I'm plugging 25-feet into 50-feet, a total of 75-feet. At 75-feet, the recommendation is 8-gauge. I have not seen an 8-gauge, 50-foot extension, nor would it take into consideration the 25-feet of 10-gauge for the main trailer. Am I just over-thinking this? Is it an issue?

[2oldman]

10 gauge should be fine, I run 60' of it running air con and it's fine. From what I see on Amazon, if you want to go 8 or 6 gauge, you'd need a 50a extension.